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AC 43.13-1B - Basco Group, LLC

1. 100006 0010 24 INCLUSIVE 7V4 INCHES 3 TO MIL H 8788 HOSE WITH NO FLEXING DASH MO BEND RADII 1 16 x 6 5 TAN VOT dues LENA inm S NNT HH He NANT Wi TOA eA AN 8788 HOSE 12 SIZE AT 1500 PSI AND HAVING A FLEXING MINIMUM BEND RADIUS AT INSIDE OF BEND Lt gt lt e par zx v t m hed a n ted i LUNN TT HHH TN ELLE LLLI LEUTE LLLI LLL Und illl MEASURED AT INSIDE OF BEND OPERATING PRESSURE POUNDS 5Q RANGE OF 60 TOTAL FLEXING RANGE OF INSTALLED HOSE DEGREES 001271 GNIE m vum m m um E um m MINIMUM BEND RADII MEASURED DIMENSIONS IN INCHES um See mam pu Gs uu duh chon cm um Gad MINIMUM BEND RADIUS OF HOSE UNDER FLEXING CONDITIONS N x NO FLEXING LIC ISI III PEE NIE GE GS URINE ERN DEN ME C ee UR E BEND RADIUS OF EITHER MIL H 8794 OR MIL H MINIMUM BEND RADII FOR 32 40 AND 48 AT ALL PRESSURES ARE AS FOLLOWS 32 EXAMPLE FOR MIL H 8794 HOSE INSIDE BEND RADII V 3HDNI SRIOVU GNIS Page 9 434 FIGURE 9 10 Minimum bend radii Par 9 30 9 8 98 AC 43 13 1B TABLE 9 4 Ball diameters for testing hose restrictions or kinking HOSE SIZE BALL SIZE 5
2. solvents with the necessary plasticizers solvent and thinners cable electrical assembly of one or more conductors within an enveloping protective sheath SO AC 43 13 1B Appendix 1 constructed as to permit use of conductors separately or in a group center of gravity that point about which the aircraft would balance if suspended For field weight and balance purposes control the center of gravity is normally calculated only along its longitudinal axis nose to tail disregarding both the lateral and vertical location certification implies that a certificate is in existence which certifies or states a qualification check a lengthwise separation of the wood the greater part of which occurs across the rings of annual growth chemical conversion coating Specification MIL C 81706 is a chemical surface treatment used on aluminum alloys to inhibit corrosion and to provide a proper surface for paint finishing circuit a closed path or mesh of closed paths usually including a source of EMF circuit breaker a protective device for opening a circuit automatically when excessive current is flowing through it close grained wood wood with narrow inconspicuous annual rings The term is sometimes used to designate wood having small and closely spaced pores but in this sense the term fine textured is more often used coil shot production of longitudinal magnetization accomplished by passing
3. AC 43 13 1B SECTION 17 CONNECTORS GENERAL The number and complexity of wiring systems have resulted in an increased use of electrical connectors The proper choice and application of connectors is a significant part of the aircraft wiring system Connectors must be kept to a minimum selected and installed to provide the maximum degree of safety and reliability to the aircraft For the installation of any particular connector assembly the specification of the manufacturer or the appropriate governing agency must be followed SELECTION The connector used for each application should be selected only after a careful determination of the electrical and environmental requirements Consider the size weight tooling logistic maintenance support and compatibility with standardization programs For ease of assembly and maintenance connectors using crimped contacts are generally chosen for all applications except those requiring an hermetic seal Reference SAE ARP 1308 Preferred Electrical Connectors For Aerospace Vehicles and Associated Equipment A replacement connector of the same basic type and design as the connector it replaces should be used With a crimp type connector for any electrical connection the proper insertion or extraction tool must be used to install or remove wires from such a connector Refer to manufacturer or aircraft instruction manual After the connector is disconnected inspect it for loose soldered
4. Visual Check Check for physical condition and safety of equipment and components Operation Check This check is performed primary by the pilot but may also be performed by the mechanics after annual and 100 hour inspections The aircraft flight manual the Airman s Information Manual AIM and the manufacturer s information are used as a reference when performing the check Functional Test This is performed by qualified mechanics and repair stations to check the calibration and accuracy of the avionics with the use of test equipment while they are still on the aircraft such as the transponder and the static checks The equipment manufacturer s manuals and procedures are used as a reference Bench Test When using this method the unit or instrument is removed from the aircraft and inspected repaired and calibrated as required Electromagnetic Interference EMI For EMI tests refer to chapter 11 paragraph 11 107 of this AC HANDLING OF COMPONENTS Any unit containing electronic components such as transistors diodes integrated circuits proms roms and memory devices should be protected from excessive shocks Excessive shock can cause internal failures in an of these components Most electronic devices are subject to damage by electrostatic discharges ESD CAUTION To prevent damage due to excessive electrostatic discharge proper gloves finger cots or grounding bracelets should be used Observe the standard
5. Weight of ballast required in pounds Compute the new of the aircraft with ballast installed NOTE If greater accuracy is desired repeat the entire formula using the NEW aircraft weight and the NEW in the second operation FIGURE 10 19 Permanent ballast computation formula Par 10 22 Page 10 480 9 8 98 AC 43 13 1B LOADING SCHEDULE The loading schedule should be kept with the aircraft and form a part of the aircraft flight manual It includes instructions on the proper load distribution such as filling of fuel and oil tanks passenger seating restrictions of passenger movement and distribution of cargo Other means of determining safe loading conditions such as the use of a graphical index and load adjuster are Par 11 1 Page 11 481 9 8 98 AC 43 13 1B acceptable and may be used in lieu of the information in paragraph 10 18 Compute a separate loading condition when the aircraft is to be loaded in other than the specified conditions shown in the loading schedule 10 24 10 34 RESERVED Par 11 1 Page 11 482 9 8 98 AC 43 13 1B CHAPTER 11 AIRCRAFT ELECTRICAL SYSTEMS SECTION 1 INSPECTION AND CARE OF ELECTRICAL SYSTEMS GENERAL The term electrical system as used in this AC means those parts of the aircraft that generate distribute and use electrical energy including their support and attachments The satisfactory performance of an aircraft is dependent upon the continued reli
6. 2 Wire bundles of 15 or more wires with wires carrying no more than 20 percent of the total current carrying capacity of the bundle as given in Specification MIL W 5088 ASG 3 Protectors in 75 to 85 F ambient 4 Copper wire Specification MIL W 5088 5 Circuit breakers to Specification MIL C 5809 or equivalent 6 Fuses to Specification MIL F 15160 or equivalent RESETTABLE CIRCUIT PROTECTION DEVICES All resettable type circuit breakers must open the circuit irrespective of the position of the operating control when an overload or circuit fault exists Such circuit breakers are referred to as trip free Automatic reset circuit breakers that automatically reset themselves periodically are not recommended as circuit protection devices for aircraft CIRCUIT BREAKER USAGE Circuit breakers are designed as circuit protection for the wire see paragraph 11 48 and 11 49 not for protection of black boxes 9 8 98 or components and are not recommended for use as switches Use of a circuit breaker as a switch will decrease the life of the circuit breaker CIRCUIT BREAKER MAINTENANCE Circuit breakers should be periodically cycled with no load to enhance contact performance by cleaning contaminants from the contact surfaces SWITCHES In all circuits where a switch malfunction can be hazardous a switch specifically designed for aircraft service should be used These switches are of rugged construction an
7. Damaged discolored or overheated connections wiring and installations equipment Excessive heat or discoloration at high current carrying connections Misalignment of electrically driven equipment Poor electrical bonding broken disconnected or corroded bonding strap and grounding including evidence of corrosion Dirty equipment and connections Improper broken inadequately supported wiring and conduit loose connections of terminals and loose ferrules Poor mechanical or cold solder joints Condition of circuit breaker and fuses Insufficient clearance between exposed current carrying parts and ground or poor insulation of exposed terminals Broken or missing safety wire broken bundle lacing cotter pins etc Operational check of electrically operated equipment such as motors inverters generators batteries lights protective devices etc Ensure that ventilation and cooling air passages are clear and unobstructed 9 8 98 Voltage check of electrical system with portable precision voltmeter Condition of electric lamps Missing safety shields on exposed high voltage terminals i e 115 200V ac FUNCTIONAL CHECK OF STAND BY OR EMERGENCY EQUIPMENT An aircraft should have functional tests performed at regular intervals as prescribed by the manufacturer The inspections or functional check periods should be clearly stated in the aircraft maintenance manual along with the overhaul interva
8. FIGURE 10 8 Weighing point centerline 10 3 10 13 RESERVED Par 10 2 Page 10 466 and 10 10 Par 10 14 9 8 98 AC 43 13 1B SECTION 2 WEIGHING PROCEDURES GENERAL Weighing procedures may vary with the aircraft and the type of weighing equipment employed The weighing procedures contained in the manufacturer s maintenance manual should be followed for each particular aircraft PROCEDURES Accepted procedures when weighing an aircraft are Remove excessive dirt grease moisture etc from the aircraft before weighing Weigh the aircraft inside a closed building to prevent error in scale reading due to wind Determine the c g by placing the aircraft in a level flight attitude Have all items of equipment that are included in the certificated empty weight installed in the aircraft when weighing These items of equipment are a part of the current weight and balance report The scales should have a current calibration before weighing begins Zero and use the scales in accordance with the scale manufacturer s instructions Platform scales and suitable support for the aircraft if necessary are usually placed under the wheels of a landplane the keel of a seaplane float or the skis of a skiplane Other structural locations capable of supporting the aircraft such as jack pads may be used Clearly indicate these points and the alternate equipment used in the weight and balance report Page 10 467 Drain
9. TERMINAL MARKING SLEEVE AND TAGS Typical cable markers are flat nonheat shrinkable tags Heat shrinkable marking sleeves are available for marking wires and cables and should be inserted over the proper wire or cable and heat shrunk using the proper manufacturer recommended heating tool See figures 11 26 and 11 27 BEFORE INSTALLATION AFTER INSTALLATION IGURE 11 26 Standard sleeves 135 C Par 11 218 AC 43 13 1B FIGURE 11 27 Installation of heat shrinkable insulation sleeves SLEEVES AND CABLE MARKERS SELECTION Sleeves and cable markers must be selected by cable size and operating conditions See tables 11 18 through 11 21 Markers are printed using a typewriter with a modified roller Blank markers on a bandolier are fed into the typewriter where they are marked in any desired combination of characters The typed markers still on bandoliers are heated in an infrared heating tool that processes the markers for permanency The typed and heat treated markers remain on the bandolier until ready for installation Markers are normally installed using the following procedure Select the smallest tie down strap that will accommodate the outside diameter of the cable See table 11 22 Cut the marking plate from the bandolier See figure 11 28 Thread the tie down straps through holes in marking plate and around cable Thread tip of tie down strap through slot in head See figure 11 29 Pull
10. WIRE IDENTIFICATION NUMBER ON WHITE INSULATION SLEEVE UNDER CLEAR SLEEVE FIGURE 11 32 Temporary wire identification marker With a pen or a typewriter write wire number on good quality white split insulation sleeve Trim excess white insulation sleeve leaving just enough for one wrap around wire to be marked with number fully visible Position marked white insulation sleeve on wire so that shielding ties clamps or supporting devices need not be removed to read the number Obtain clear plastic sleeve that is long enough to extend 1 4 inch past white insulation sleeve marker edges and wide enough to overlap itself when wrapped around white insulation and wire Slit clear sleeve lengthwise and place around marker and wire Par 11 230 Page 11 570 9 8 98 AC 43 13 1B Secure each end of clear sleeve with lacing tape spot tie to prevent loosening of sleeve MARKER SLEEVE INSTALLATION AFTER PRINTING The following general procedures apply Hold marker printed side up and press end of wire on lip of sleeve to open sleeve See figure 11 33 FIGURE 11 33 Inserting wire into marker If wire has been stripped use a scrap piece of unstripped wire to open the end of the marker Push sleeve onto wire with a gentle twisting motion Shrink marker sleeve using heat gun with shrink tubing attachment See figure 11 34 FIGURE 11 34 Shrinking marker on wire 11 223 11 229 RESERVED Par 11 230 Page 11 571 9 8 98
11. queam a eea Toa 4206 37988 Divide the TM total moment by the TW total weight to obtain the loaded center of gravity TM 37988 18 7 TW 20366 The above computations show that with maximum baggage full fuel and 2 passengers 1 in the front seat and 1 in the rear seat may be carried in this aircraft without exceeding either the maximum weight or the approved C G range This condition may be entered in the loading schedule as follows Conditions as entered from Figure 10 12 Conditions as entered from Figure 10 13 F Front seat R Rear seat FIGURE 10 14 Loading conditions determination of the fuel and the number and location of passengers permissible with maximum baggage Par 10 20 Page 10 475 9 8 98 FORWARD C G LIMIT AC 43 13 1B WEIGHTS REARWARD C G LIMIT Weights added anywhere between the C G limits will not upset the balance of the aircraft WEIGHT FORWARD LIMIT KMC REARWARD LIMIT Any weights added ahead of the forward C G limit would tend to upset the balance around the forward balance limit FORWARD C G LIMIT l REARWARD C G LIMIT Any weights added aft of the rearward C G limit would tend to upset the balance around the rearward balance limit FIGURE 10 15 Effects of the addition of equipment items on balance Moment computations for typical equipment changes are given in figure 10 16 and a
12. 1 43428 Divide the TM total moment by the TW total weight to obtain the rearward weight and balance extreme TM 43428 21 3 TW 2036 Since the rearward C G limit and the maximum weight are not exceeded the rearward weight and balance extreme condition is satisfactory FIGURE 10 11 Example of check of most rearward weight and balance extreme Par 10 17 Page 10 472 9 8 98 AC 43 13 1B EXAMPLE OF THE DETERMINATION OF THE NUMBER OF PASSENGERS AND BAGGAGE PERMISSIBLE WITH FULL FUEL GIVEN Actual empty weight of the aircraft Empty weight center of gravity Maximum weight Datum is leading edge of the wing Forward center of gravity limit Rearward center of gravity limit Oil capacity 9 qts show full capacity Baggage maximum Two passengers in rear seat 170 x 2 Pilot in most rearward seat equipped with controls unless otherwise placarded 170 at 16 Full fuel 40 gals x 6 240 at 22 pO Weight xAm Moment 7 m e 2720 Baggage 7550 2036 TW 43428 TM Divide the TM total moment by the TW total weight to obtain the loaded center of gravity TM 43428 21 3 TW 2036 The above computations show that with full fuel 100 pounds of baggage and two passengers in the rear seat may be carried in this aircraft without exceeding either the maximum weight or the approved C G range This condition may be entered in the loading sched
13. Locator Beacon and Battery Lines and Anchor Police Whistle Flashlight Space Blankets if required Light sticks Solar Still Kit Survival Manual Duct Tape Plastic Trash Bags Accessory Containers Bailing Bucket Sponge Dye Marker Shark Chaser 9 8 98 AC 43 13 1B DOWN PULL Remove Deflector before connecting to raft FIGURE 9 12 Inflation valve Exposure Suits Quick donning exposure suits should be provided in sufficient quantity to accommodate the passengers and crew on extended over water missions whenever any of the following conditions exist The water temperature is 59 F or below or The Outside Air Temperature OAT is 32 F or below Physical Inspection Make a physical inspection of the life raft s accessories and or contents in accordance with manufacturer s specifications to ascertain that all items required are in a serviceable condition Pumps and Hoses Check the air pump for condition and security Check the air pump hose and hose fittings for ease of attachment to the pump and mattress valves Par 9 39 Page 9 438 Operate the pump to ensure that it delivers air Close the outlet and check the seal of the piston Blow into the outlet to determine if the pump check valve will seal Desalting Kit Check the desalting kit expiration date if applicable Replace the severely dented or punctured cans NOTE Type MK 2 desalter kits have an indefinite shelf a
14. MIL W 22759 8 MIL W 22759 9 MIL W 22759 10 MIL W 22759 13 MIL W 22759 16 Fluoropolymer insulated extruded Tin coated copper MIL W 22759 17 Fluoropolymer insulated extruded Silver coated high strength copper alloy MIL W 22759 20 Fluoropolymer insulated extruded TFE Silver coated high strength copper alloy MIL W 22759 21 Fluoropolymer insulated extruded TFE Nickel coated high strength copper alloy MIL W 22759 34 Fluoropolymer insulated crosslinked Tin coated copper modified ETFE MIL W 22759 35 Fluoropolymer insulated crosslinked Silver coated high strength modified ETFE copper alloy MIL W 22759 41 Fluoropolymer insulated crosslinked Nickel coated copper modified ETFE MIL W 22759 42 Fluoropolymer insulated crosslinked Nickel coated high strength modified ETFE copper alloy MIL W 22759 43 Fluoropolymer insulated crosslinked Silver coated copper modified ETFE MIL W 25038 3 2 See specification sheet See specification sheet MIL W 81044 6 Crosslinked polyalkene Tin coated copper MIL W 81044 7 Crosslinked polyalkene Silver coated high strength copper alloy MIL W 81044 9 Crosslinked polyalkene Tin coated copper MIL W 81044 10 Crosslinked polyalkene Silver coated high strength copper alloy Par 11 85 Page 11 521 9 8 98 AC 43 13 1B TABLE 11 12 Protected wiring Document Voltage Rated wire Insulation Type Conductor type rating temperature maximum C MIL W 22759 11 20 Fluoropolymer insulated extruded TFE Silver c
15. Power Supply Purposes Test Blocks Coaxial Connector Waveguide Flanges Waveguide Junction Par 11 272 Page 11 595 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Lightning Arrester Arrester Gap Circuit Breaker Protective Relay Audible Signaling Device Microphone Par 11 272 Page 11 596 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Handset Operator s Set Visual Signaling Device Mechanical Connection Mechanical Interlock Mechanical Motion Clutch Brake Par 11 272 Page 11 597 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Manual Control Gyro Gyroscope Gyrocompass mE Fire Extinguisher Actuator Head E a ate 5 Par 12 1 Page 12 598 and 12 2 9 8 98 AC 43 13 1B Integrated Circuit 3 Amplifiers GENERAL SYMBOLS MAGNETIC AMPLIFIER INVERTOR OR NOT GATE a 1 2 Logic Gates AND GATE WITH THREE INPUTS NAND NOT AND GATE do do OR GATE NOR NOT OR GATE gt D EXCLUSIVE OR GATE Transistor Symbols EMITTER BASE COLLECTOR E C EMITTER BASE COLLECTOR 11 273 11 283 RESERVED Par 12 1 Page 12 599 and 12 2 Par 12 1 9 8 98 AC 43 13 1B CHAPTER 12 AIRCRAFT AVIONICS SYSTEMS SECTION 1 AVIONICS EQUIPMENT MAINTENANCE GENERAL There are several methods of ground checking avionics systems
16. The voltage source is 28 volts from bus to equipment The circuit has continuous operation Estimated conductor temperature is 20 C or less The scale on the left of the chart represents maximum wire length in feet to prevent an excessive voltage drop for a specified voltage source system e g 12V 28V 115V 200V This voltage is identified at the top of scale and the corresponding voltage drop limit for continuous operation at the bottom The scale slant lines on top of the chart represents amperes The scale at the bottom of the chart represents wire gauge 9 8 98 STEP 1 From the left scale find the wire length 50 feet under the 28V source column STEP 2 Follow the corresponding horizontal line to the right until it intersects the slanted line for the 20 amp load STEP 3 At this point drop vertically to the bottom of the chart and select the next wire size to the right This is the smallest size wire that can be used without exceeding the voltage drop limit expressed at the bottom of the left scale This example is plotted on the wire chart figure 11 2 Use figure 11 2 for continuous flow and figure 11 3 for intermittent flow Procedures in Example No 1 The procedures in example No 1 paragraph 11 68c can be used to find the wire size for any continuous or intermittent operation maximum two minutes Voltage e g 12 volts 28 volts 115 volts 200 volts as indicated on the left scale of the wire chart in f
17. condition checks and are not covered by suitable placards in the aircraft additional computations are necessary These computations should indicate the permissible distribution of fuel passengers and baggage that may be carried in the aircraft at any one time without exceeding either the maximum weight or c g range The conditions to check are With full fuel determine the number of passengers and baggage permissible With maximum passengers determine the fuel and baggage permissible With maximum baggage determine the fuel and the number and location of passengers Examples of the computations for the above items are given in figures 10 12 10 13 and 10 14 respectively The above cases are mainly applicable to the lighter type personal aircraft In the case of the larger type transport aircraft a variety of loading conditions is possible and it is necessary to have a loading schedule EQUIPMENT LIST A list of the equipment included in the certificated empty weight may be found in either the approved aircraft flight manual or the weight and balance report Enter into the weight and balance Par 10 17 Page 10 471 AC 43 13 1B report all required optional and special equipment installed in the aircraft at time of weighing and or subsequent equipment changes Required equipment items are listed in the pertinent Aircraft Specifications Optional equipment items are listed in the pertinent Aircraft Specifications
18. etc used in weight and balance calculations Normally only the longitudinal arm is of practical importance The three axial arms are longitudinal arm lateral arm and vertical arm automatic direction finder ADF a radio receiver utilizing a directional loop antenna that enables the receiver to indicate the direction from which a radio signal is being received also called a radio compass automatic flight control system AFCS a flight control system incorporating an automatic pilot with additional systems such as a VOR coupler an ILS approach coupler and an internal navigation system that is fully automatic so the aircraft can be flown in a completely automatic mode avionics the science and technology of electronics as applied to aviation azimuth angular distance measured on a horizontal circle in a clockwise direction from either north or south balance the condition of stability which exists in an aircraft when all weight and forces are acting in such a way as to prevent rotation about an axis or pivot point base metal the metal to be welded brazed soldered or cut black light electromagnetic radiation in the near ultraviolet range of wavelength 617 9 8 98 blade station is a reference position on a blade that is a specified distance from the center of the hub bond the adhesion of one surface to another with or without the use of an adhesive as a bonding agent bonding a ge
19. me FILTER DIRECTIONAL GYRO SUCTION AGE SEPARATOR 2 OR TO DEICER VACUUM PUMP ENGINE OIL METERED INTO PUMP FOR COOLING amp SEALING AIR OVERBOARD DISTRIBUTOR VALVE OIL RETURN TO ENGINE CRANKCASE FIGURE 12 2 Instrument vacuum system using a wet type vacuum pump broken off of one vane will damage all of the other vanes To prevent particles entering the relief valve its air inlet is covered with a filter and this must be cleaned or replaced at the interval recommended by the aircraft manufacturer Positive Pressure Systems Above about 18 000 feet there is not enough mass to the air drawn through the instruments to provide sufficient rotor speed and to remedy this problem many aircraft that fly at high altitude use positive pressure systems to drive the gyros These systems use the same type of air pump as is used for vacuum systems but the discharged air from the pump is filtered and directed into the instrument case through the same fitting that receives the filtered air when the vacuum system is used A filter is installed on the inlet of the pump and then before the air is directed into the instrument case it is again filtered A pressure regulator is located between the pump and the Par 12 38 in line filter to control the air pressure so only the correct amount is directed into the instrument case System Filters The life of an air driven gyro instrument
20. other conditions that may lead to failure Tubular structures for such gear may be repaired as described in the section covering welded repairs of tubular structures Floats To maintain the float in an airworthy condition periodic and frequent inspections should be made because of the rapidity of corrosion on metal parts particularly when the aircraft is operated in salt water Examine metal floats and all metal parts on wooden or fiberglass floats for corrosion and take corrective action in accordance with the procedures described in Chapter 6 Corrosion Inspection amp Protection Chapter 4 Metal Structure Welding and Brazing outlines methods for repairing damage to metal floats of aluminum and aluminum alloy structures In the case of wooden floats make repairs in accordance with general procedures outlined in Chapter 1 Wood Structure Repair fiberglass floats in accordance with the manufacturer s instructions If small blisters are noticed on the paint either inside or outside the float the paint should be removed and the area examined If corrosion is found the area should be cleaned thoroughly and a coat of corrosion inhibiting material applied lf the corrosion penetrates the metal to an appreciable depth replace the metal Special attention should be given to brace wire fittings and water rudder control Systems If the hull or floats have retractable landing gear a retraction check should be performed along
21. questionable cases consult the local representative of the FAA concerning the airworthiness of the wheels Minor dents do not affect the serviceability of a wheel Wheel bearings When inspecting wheel bearings for condition replace damaged or excessively worn parts Maintain bearings and races as matched sets Pack bearings only with the grease type called for in the manufacturer s maintenance manual prior to their installation Avoid pre loading the wheel bearing when installing it on the aircraft by tightening the axle nut just enough to prevent wheel drag or side play Par 9 7 Page 9 414 AC 43 13 1B Brakes Disassemble and inspect the brakes periodically and examine the parts for wear cracks warpage corrosion elongated holes etc Discolored brake disks are an indication of overheated brakes and should be replaced If any of these or other faults are indicated repair recondition or replace the affected parts accordance with the manufacturer s recommendations Hydraulic Brakes For proper maintenance periodically inspect the entire hydraulic system from the reservoir to the brakes Maintain the fluid at the recommended level with proper brake fluid When air is present in the brake system bleed in accordance with the manufacturer s instructions Replace flexible hydraulic hoses which have deteriorated due to long periods of service and replace hydraulic piston seals when there is evidence of leakage M
22. should be considered when determining the number of terminals to be attached to any one post In high temperature applications the terminal temperature rating must be greater than the ambient temperature plus current related temperature rise Use of nickel plated terminals and of uninsulated terminals with high temperature insulating sleeves should be considered Terminal blocks should be provided with adequate electrical clearance or insulation strips between mounting hardware and conductive parts Page 11 547 Terminal Strips Wires are usually joined at terminal strips A terminal strip fitted with barriers should be used to prevent the terminals on adjacent studs from contacting each other Studs should be anchored against rotation When more than four terminals are to be connected together a small metal bus should be mounted across two or more adjacent studs In all cases the current should be carried by the terminal contact surfaces and not by the stud itself Defective studs should be replaced with studs of the same size and material since terminal strip studs of the smaller sizes may shear due to overtightening the nut The replacement stud should be securely mounted in the terminal strip and the terminal securing nut should be tight Terminal strips should be mounted in such a manner that loose metallic objects cannot fall across the terminals or studs It is good practice to provide at least one spare stud for future circuit ex
23. the equipment has been located and installed in accordance with the manufacturer s recommendations The wire insulation temperature rating should also be considered Power input tests must be conducted with the equipment powered by the airplane s electrical power generating system unless otherwise specified All associated electrically operated equipment and systems on the airplane must be on and operating before conducting interference tests unless otherwise specified The effects on interference must be evaluated as follows The equipment shall not be the source of harmful conducted or radiated interference or adversely affect other equipment or systems installed in the airplane 9 8 98 43 13 1 With the equipment energized on the ground individually operate other electrically operated equipment and systems on the airplane to determine that no significant conducted or radiated interference exists Evaluate all reasonable combinations of control settings and operating modes Operate communication and navigation equipment on at least one low high and mid band frequency Make note of systems or modes of operation that should also be evaluated during flight For airplane equipment and systems that can be checked only in flight determine that no operationally significant conducted or radiated interference exists Evaluate all reasonable combinations of control settings and operating modes Operate communications and navigatio
24. which could damage the insulation and foul mechanical linkages or other moving mechanical parts They also may not be used where they could be exposed to UV light unless the straps are resistant to such exposure Lacing Lace wire groups or bundles inside junction boxes or other enclosures Single cord lacing method shown in figure 11 15 and tying tape meeting specification MIL T 43435 may be used for wire groups of bundles 1 inch in diameter or less The recommended knot for starting the single cord lacing method is a clove hitch secured by a double looped overhand knot as shown in figure 11 15 step a Use the double cord lacing method on wire bundles 1 inch in diameter or larger as shown in figure 11 16 When using the double cord lacing method employ a bowline on a bight as the starting knot Use wire group or bundle ties where the wire are more Tying supports for Par 11 155 All numbers of strands Page 11 543 19 2 nicked none broken 37 4 nicked none broken 133 6 nicked 6 broken 665 817 6 nicked 6 broken 1 045 1 330 6 nicked 6 broken 1 665 6 nicked 6 broken 2 109 6 nicked 6 broken None None 12 inches apart A tie consists of a clove hitch around the wire group or bundle secured by a square knot as shown in figure 11 17 Plastic Ties Refer to Paragraph 11 220 and table 11 21 INSULATION TAPE Insulation tape should be of a type suitable for the application or as specified for th
25. with an abundance of water If potassium hydroxide contacts the skin neutralize with 9 percent acetic acid vinegar or lemon juice and wash with water For the eyes wash with a weak solution of boric acid or a weak solution of vinegar and flush with water NOXIOUS FUMES When charging rates are excessive the electrolyte may boil to the extent that fumes containing droplets of the electrolyte are emitted through the cell vents These fumes from lead acid batteries may become noxious to the crew members and passengers therefore thoroughly check the venting system NiCad batteries will emit gas near the end of the charging process and during overcharge The battery vent system in the aircraft should have sufficient air flow to prevent this explosive mixture from accumulating It is often advantageous to install a jar in the battery vent discharge system serviced with an agent to neutralize the corrosive effect of battery vapors INSTALLATION PRACTICES External Surface Clean the external surface of the battery prior to installation in the aircraft Replacing Lead Acid Batteries When replacing lead acid batteries with NiCad batteries a battery temperature or current monitoring system must be installed Neutralize the battery box or compartment and thoroughly flush with water and dry A flight manual supplement must also be provided for the NiCad battery installation Acid residue can be detrimental to the proper functioning of
26. 11 37 Coax cable connectors continued Par 11 232 Page 11 576 9 8 98 AC 43 13 1B w MHV Series Connector QSC Series Connector E E QSC Series Connector SHV Series Connector FIGURE 11 37 Coax cable connectors continued power or signal distribution When used as grounding VOLTAGE AND CURRENT RATING Selected modules they save and reduce hardware installation on connectors must be rated for continuous the aircraft Standardized modules are available with operation under the maximum combination of wire end grommet seals for environmental applications ambient temperature and circuit current load and are track mounted Function module blocks are Hermetic connectors and connectors used in used to provide an easily wired package for circuit applications involving high inrush environment resistant mounting of small resistors currents should be derated It is good diodes filters and suppression networks In line engineering practice to conduct preliminary terminal junctions are sometimes used in lieu of a testing in any situation where the connector is connector when only a few wires are terminated and to operate with most or all of its contacts at when the ability to disconnect the wires is desired The maximum rated current load When wiring is in line terminal junction is environment resistant The operating with a high conductor temperature terminal junction splice is small and may be tied to the near its rated te
27. 18 Splices should not be used within 12 inches of a termination device except for paragraph f below Splices may be used within 12 inches of a termination device when attaching to the pigtail spare lead of a potted termination device or to splice multiple wires to a single wire or to adjust the wire sizes so that they are compatible with the contact crimp barrel sizes Selection of proper crimping tool refer to paragraph 11 178 jo a aa ao FIGURE 11 18 Staggered splices in wire bundle 11 168 11 173 RESERVED Page 11 546 and 11 66 Par 11 174 9 8 98 43 13 1 SECTION 14 TERMINAL REPAIRS GENERAL Terminals are attached to the ends of electrical wires to facilitate connection of the wires to terminal strips or items of equipment The tensile strength of the wire to terminal joint should be at least equivalent to the tensile strength of the wire itself and its resistance negligible relative to the normal resistance of the wire Selection of Wire Terminals The following should be considered in the selection of wire terminals Current rating Wire size gauge and insulation diameter Conductor material compatibility Stud size Insulation material compatibility Application environment Solder solderless Pre insulated crimp type ring tongue terminals are preferred The strength size and supporting means of studs and binding posts as well as the wire size
28. 1987 Determination of Electrical Properties of Bonding and Fastening Techniques may provide additional information for composite materials Control Surface Lightning Protection Bonding Control surface bonding is intended to prevent the burning of hinges on a surface that receives a lightning strike thus causing possible loss of control To accomplish this bonding control surfaces and flaps should have at least one 6500 circular mil area copper e g 7 by 37 AWG size 36 strands jumper 9 8 98 across each hinge In any case not less than two 6500 circular mil jumpers should be used on each control surface The installation location of these jumpers should be carefully chosen to provide a low impedance shunt for lightning current across the hinge to the structure When jumpers may be subjected to arcing substantially larger wire sizes of 40 000 circular mils or a larger cross section are required to provide protection against multiple strikes Sharp bends and loops in such jumpers can create susceptibility to breakage when subjected to the inductive forces created by lightning current and should be avoided Control Cable Lightning Protection Bonding To prevent damage to the control system or injury to flight personnel due to lightning strike cables and levers coming from each control surface should be protected by one or more bonding jumpers located as close to the control surface as possible Metal pulleys are considered a satisfa
29. 2100 Approved aft limit 21 9 Item Weight X Arm Moment Airo Empty 1169 12391 12391 9 or 12a 11 or 12c 9 or 12a 11 or 12c Oil 833 Pilot 2720 Fuel 5280 emer J 4 1628 Bae 1535 TOTAL 1439 TW 16104 TM 2036 TW 43428 16104 112 43428 21 3 TW 1439 TW 2036 Most Forward location Most Rearward C G location LOADING SCHEDULE Gallons Number of Pounds of of Fuel Passengers Baggage The above includes pilot and capacity oil EQUIPMENT CHANGE Computing New C G Item Make and Model Weight X Arm Moment Airc Empty 1169 10 6 12391 9 or 12a 11 or 12c 204 added 302 b added 30307 302 a removed 2599 o 9698 303 removed __ _ 6 1 um 1 4 NET TOTALS 1179 NW 13454 NM NM 13454 11 4 New NW 1179 ITEM NUMBERS WHEN LISTED IN PERTINENT AIRCRAFT SPECIFICATION MAY BE USED IN LIEU OF ITEM MAKE AND MODEL PREPARED BY DATE FIGURE 10 18 Sample weight and balance report including an equipment change for aircraft fully loaded Par 10 22 Page 10 479 9 8 98 AC 43 13 1B Desired location Actual location Location of ballast to Distance in inches desired to move C G of airplane be added Weight of airplane as loaded Distance in inches from point where ballast is to be installed to the desired location of the new C G
30. 64 9 64 13 64 9 32 3 8 1 2 47 64 FIGURE 9 11 Suggested handling of preformed hose 9 31 9 36 RESERVED Par 9 30 Page 9 435 and 9 26 9 8 98 Par 9 37 AC 43 13 1B SECTION 3 EMERGENCY EQUIPMENT LIFE RAFTS Inflatable life rafts are subject to general deterioration due to aging Experience has indicated that such equipment may be in need of replacement at the end of 5 years due to porosity of the rubber coated material Wear of such equipment is accelerated when stowed on board aircraft because of vibration which causes chafing of the rubberized fabric This ultimately results in localized leakage Leakage is also likely to occur where the fabric is folded because sharp corners are formed When these corners are in contact with the carrying cases or with adjacent parts of the rubberized fabric they tend to wear through due to vibration Ref TSO C70a When accomplishing maintenance repair and inspection of unpacked rafts personnel should not step on any part of the raft or flotation tubes while wearing shoes Rafts should not be thrown or dropped since damage to the raft or accessories may result Particular care should be exercised at all times to prevent snagging cutting and contact with gasoline acids oils and grease High standards of performance for proper maintenance inspection and repair cannot be overemphasized since the lives of passengers could be involved Inspection and inflatio
31. 68 Page 11 513 9 8 98 The resultant maximum wire length after adjusting downward for the added resistance associated with running the wire at a higher temperature is 15 3 feet which will meet the original 15 foot wire run length requirement without exceeding the voltage drop limit expressed in figure 11 2 COMPUTING CURRENT CARRYING CAPACITY Example 1 Assume a harness open or braided consisting of 10 wires size 20 200 C rated copper and 25 wires size 22 200 C rated copper will be installed in an area where the ambient temperature is 60 C and the vehicle is capable of operating at a 60 000 foot altitude Circuit analysis reveals that 7 of the 35 wires in the bundle 7 35 20 percent will be carrying power currents nearly at or up to capacity STEP 1 Refer to the single wire in free air curves in figure 11 4a Determine the change of temperature of the wire to determine free air ratings Since the wire will be in an ambient of 60 C and rated at 200 C the change of to temperature is 200 60 C 140 Follow the 140 C temperature difference horizontally until it intersects with wire size line on figure 11 4a The free air rating for size 20 is 21 5 amps and the free air rating for size 22 is 16 2 amps STEP 2 Refer to the bundle derating curves in figure 11 5 the 20 percent curve is selected since circuit analysis indicate that 20 percent or less of the wire in the harness would be car
32. 98 AC 43 13 1B may normally be avoided by insulating the terminal posts during the installation process Remove the grounding lead first for battery removal then the positive lead Connect the grounding lead of the battery last to minimize the risk of shorting the hot terminal of the battery during installation Battery Hold Down Devices Ensure that the battery hold down devices are secure but not so tight as to exert excessive pressure that may cause the battery to buckle causing internal shorting of the battery Par 11 30 Page 11 491 9 8 98 AC 43 13 1B Quick Disconnect Type Battery If a quick disconnect type of battery connector that prohibits crossing the battery lead is not employed ensure that the aircraft wiring is connected to the proper battery terminal Reverse polarity in an electrical system can seriously damage a battery and other electrical components Ensure that the battery cable connections are tight to prevent arcing or a high resistance connection 11 23 11 29 RESERVED Par 11 30 Page 11 492 9 8 98 AC 43 13 1B SECTION 3 INSPECTION OF EQUIPMENT INSTALLATION GENERAL When installing equipment which consumes electrical power in an aircraft it should be determined that the total electrical load can be safely controlled or managed within the rated limits of the affected components of the aircraft s electrical power supply system Addition of most electrical utilization equipment is a majo
33. Arm The arm or moment arm is the horizontal distance in inches from the datum to the c g of an item The algebraic sign is plus if measured aft of the datum and minus if measured forward of the datum Examples of plus and minus arms are shown in figure 10 2 9 8 98 AC 43 13 1B ANY CONVENIENT DISTANCE FIGURE 10 1 Typical datum locations Par 10 2 Page 10 459 9 8 98 OIL COOLER 5LBS ARM 20 MINUS ARM FIGURE 10 2 Illustration of arm or moment arm Moment The moment is the product of a weight multiplied by its arm The moment of an item about the datum is obtained by multiplying the weight of the item by its horizontal distance from the datum A typical moment calculation is given in figure 10 3 Center of Gravity The c g is a point about which the nose heavy and tail heavy moments are exactly equal in magnitude If the aircraft is suspended from the c g it will not have a tendency to pitch in either direction nose up or down The weight of the aircraft or any object may be assumed to be concentrated at its c g See figure 10 3 Empty Weight Center of Gravity The empty weight c g is the c g of an aircraft in its empty weight condition and is an essential part of the weight and balance record Formulas for determining the c g for tail and nosewheel type aircraft are given in figure 10 4 Typical examples of computing the empty weight and empty weight c g for aircraft are shown in figu
34. Check smoothness of operation with particular attention to altimeter performance during decent Contact an appropriate air traffic facility for the pressure altitude displayed to the controller from your aircraft Correct the reported altitude as needed and compare to the reading on the altimeter instrument The difference must not exceed 125 feet TRANSPONDERS There are three modes types of transponders that can be used on various aircraft Mode A provides a non altitude reporting four digit coded reply Mode C provides a code reply identical to Mode A with an altitude reporting signal and Mode S has the same capabilities as Mode A and Mode C and responds to traffic alert and collision avoidance system TCAS Equipped Aircraft Ground ramp equipment must be used to demonstrate proper operation Enough codes must be selected so that each switch 9 8 98 position is checked at least once Low and high sensitivity operation must be checked Identification operation must be checked Altitude reporting mode must be demonstrated Demonstrate that transponder system does not interfere with other systems aboard the aircraft and that other equipment does not interfere with transponder operation Special consideration must be given to other pulse equipment such as DME and weather radar All transponders must be tested every 24 calendar months or during an annual inspection if requested by the owner The test must be conducte
35. ERR RES SEAR RARE RRR REDUCTIONS SHOWN ARE THE MAXIMUM ALLOWABLE BELOW THE MINIMUM DIMENSIONS REQUIRED BY THE BLADE DRAWING AND BLADE MANUFACTURING SPECIFICATION Sanne BREE Eee ECE EE EE eae 41 440 SSE EEE CECE HE o 3 t 2 o 74 o o x I 2 lt lt E a s 2 2 o a 72 RADIUS PERCENT OF REPAIRED BLADE RADIUS a Draw a vertical line at the value of r 68 on the horizontal axis b Where the vertical line intersects the curve draw a horizontal line to the right to intersect the vertical axis c Read the percent reduction in thickness At on the vertical axis intersection At 4 0 FIGURE 8 28 Example 2 Determine the repair thickness limits method will always require the re drilling of are approved under 14 CFR part 21 should be all new propellers subsequently used with the used re drilled flange DEICING SYSTEMS Components used in CONTROL SYSTEMS Components used to propeller deicing systems should be inspected control the operation of certificated propellers repaired assembled and or tested in should be inspected repaired assembled accordance with the manufacturer s and or tested in accordance with the recommendations Only those repairs which manufacturer s recommendations Only those are covered by the manufacturer s repairs wh
36. Seepage of rust inhibiting oils used to coat internal surfaces of steel tubes also assists in the early detection of cracks In addition a Sooty oily residue around bolts rivets and pins is a good indication of looseness or wear Thoroughly clean and re inspect the landing gear to determine the extent of any damage or wear Some components may require removal and complete disassembly for detailed inspection Others may require a specific check using an inspection process such as dye penetrant magnetic particle radiographic ultrasonic or eddy current The frequency degree of thoroughness and selection of inspection methods are dependent upon the age use and general condition of the landing gear Inspect the aircraft or landing gear structure surrounding any visible damage to ensure that no secondary damage remains Par 9 10 Page 9 417 AC 43 13 1B undetected Forces can be transmitted along the affected member to remote areas where subsequent normal loads can cause failure at a later date Prime locations for cracks on any landing gear are bolts bolt holes pins rivets and welds The following are typical locations where cracks may develop Most susceptible areas for bolts are at the radius between the head and the shank and in the location where the threads join the shank as shown in figure 9 2 Cracks primarily occur at the edge of bolt holes on the surface and down inside the bore See figures 9 3 and 9
37. Steel Lock washer E Cadmium Plated Steel Cadmium Plated Steel Cadmium Plated Steel Corrosion Resist Steel Cadmium Plated Steel Cadmium Plated Steel Corrosion Resisting Steel Lock washer F Cadmium Plated Steel Cadmium Plated Steel Cadmium Plated Steel Cadmium Plated Steel Cadmium Plated Steel or Aluminum Cadmium Plated Steel Corrosion Resisting Steel Avoid connecting copper to magnesium Par 11 189 Page 11 556 9 8 98 AC 43 13 1B TABLE 11 15 Plate nut bonding or grounding to flat surface LOCK WASHER SCREW OR BOLT LIMITED TO 4 WASHER A NUT PLATE Aluminum Terminal and Jumper Screw or bolt and nut plate Lockwasher Washer A Washer B Aluminum Alloys Cadmium Plated Aluminum Alloy Cadmium Plated Cadmium Plated Steel Steel Steel or Aluminum Magnesium Alloys Cadmium Plated Aluminum Alloy Cadmium Plated Cadmium Plated None or Steel Steel Steel or Magnesium Aluminum Alloy Steel Cadmium Cadmium Plated Corrosion Cadmium Plated Cadmium Plated Plated Steel Resisting Steel Steel Steel or None Aluminum Steel Corrosion Corrosion Resisting Corrosion Cadmium Plated Cadmium Plated Resisting Steel or Cadmium Resisting Steel Steel Steel or Cadmium Plated Steel Aluminum Plated Steel Tinned Copper Terminal and Jumper Aluminum Alloys Cadmium Plated Aluminum Alloy Cadmium Plated Cadmium Plated Aluminum Steel Steel Steel Alloy Magnesium Alloys Steel Cadmium Cadmiu
38. The use of properly calibrated torque wrenches and following the manufacturer s installation procedures is strongly recommended This is especially important with hermetically sealed relays since the glass to metal seal used for Page 11 500 9 8 98 insulation of the electrically live components is especially vulnerable to catastrophic failure as a result of overtorquing When replacing relays in alternating current ac applications it is essential to maintain proper phase sequencing For any application involving plug in relays proper engagement of their retaining mechanism is vital The proximity of certain magnetically permanent magnet assisted coil operated relays may cause them to have an impact on each other Any manufacturer s recommendations or precautions must be closely followed Par 11 53 Page 11 501 AC 43 13 1B LOAD CONSIDERATIONS When switches or relays are to be used in applications where current or voltage is substantially lower than rated conditions additional intermediate testing should be performed to ensure reliable operation Contact the manufacturer on applications different from the rated conditions OPERATING CONDITIONS FOR SWITCHES AND RELAYS Switches and relays should be compared to their specification rating to ensure that all contacts are made properly under all conditions of operation including vibration equivalent to that in the area of the aircraft in which the switch or
39. Wire STRIPPING INSULATION Attachment of wire to connectors or terminals requires the removal of insulation to expose the conductors This practice is commonly known stripping Stripping may be accomplished in many ways however the following basic principles should be practiced Make sure all cutting tools used for stripping are sharp When using special wire stripping tools adjust the tool to avoid nicking cutting or otherwise damaging the strands Damage to wires should not exceed the limits specified in table 11 13 When performing the stripping operation remove no more insulation than is necessary LACING AND TIES Ties lacing and straps are used to secure wire groups or bundles to provide ease of maintenance inspection and installation Braided lacing tape per MIL T 43435 is suitable for lacing and tying wires In lieu of applying ties straps meeting Specification MS17821 or MS17822 may be used in areas where the temperature does not exceed 120 Straps may not be used in areas of SWAMP such as wheel wells near wing flaps or wing folds They may not be used in high vibration areas where failure 9 8 98 TABLE 11 13 Allowable nicked or broken strands AC 43 13 1B Maximum allowable nicked and broken strands Wire Size Conductor material Number of strands per Total allowable nicked and conductor broken strands Copper Alloy Aluminum of the strap would permit wiring to move against parts
40. a NiCad battery as alkaline will be to a lead acid battery Par 11 20 Page 11 490 AC 43 13 1B Battery Venting Battery fumes and gases may cause an explosive mixture or contaminated compartments and should be dispersed by adequate ventilation Venting systems often use ram pressure to flush fresh air through the battery case or enclosure to a safe overboard discharge point The venting system pressure differential should always be positive and remain between recommended minimum and maximum values Line runs should not permit battery overflow fluids or condensation to be trapped and prevent free airflow Battery Sump Jars A battery sump jar installation may be incorporated in the venting system to dispose of battery electrolyte overflow The sump jar should be of adequate design and the proper neutralizing agent used The sump jar must be located only on the discharge side of the battery venting system See figure 11 1 AIR INTAKE AIR OUTPUT AIRPLANE SKIN FELT PAD IN SUMP JAR AIR OUTPUT c AIR INTAKE AIRPLANE SKIN FIGURE 11 1 Battery ventilating systems Installing Batteries When installing batteries in an aircraft exercise care to prevent inadvertent shorting of the battery terminals Serious damage to the aircraft structure frame skin and other subsystems avionics wire fuel etc can be sustained by the resultant high discharge of electrical energy This condition 9 8
41. a copolymer of PTFE and polyethylene exciter small generator for supplying direct current to the alternator s field windings exfoliation corrosion a form of intergranular corrosion that attacks extruded metals along their layer like grain structure expandable sleeving open weave braided sleeving used to protect wire and cables from abrasion and other hazards commonly known by trade name EXPANDO FEP fluorinated ethylene propylene commonly known by the trade name TEFLON melt extrudable fluorocarbon resin very similar in appearance and performance to PTFE but with a maximum temperature rating of 200 C ferrous metal iron or any alloy containing iron fiberglass the most common material used to reinforce structures in home built and experimental aircraft Available as mat roving fabric etc It is 620 9 8 98 incorporated into both thermoset and thermoplastic resins The glass fibers increase mechanical strength impact resistance stiffness and dimensional stability of the matrix fillthreads in a fabric that run crosswise of the woven material filiform corrosion a thread or filament like corrosion which forms on aluminum skins beneath the finish finish external coating or covering of an aircraft or part flat grain lumber has been sawed parallel with the pith of the log and approximately tangent to the growth rings that is the rings form an angle of less than 45 degrees
42. abrasion A combing tool similar to that shown in figure 11 8 may be made from any suitable insulating material taking care to Par 11 115 Page 11 532 BUNDLE TIE GROUP TIE BUNOLE TIE FIGURE 11 7 Group and bundle ties FIGURE 11 8 Comb for straightening wires in bundles ensure all edges are rounded to protect the wire insulation MINIMUM WIRE BEND RADII The minimum radii for bends in wire groups or bundles must not be less than 10 times the outside diameter of their largest wire or they may be bent at 6 times their outside diameters at breakouts or where they must reverse direction in a bundle provided that they are suitably supported RF cables should not bend on a radius of less than 6 times the outside diameter of the cable 9 8 98 AC 43 13 1B Care should be taken to avoid sharp bends in wires that have been marked with the hot stamping process SLACK Wiring should be installed with sufficient slack so that bundles and individual wires are not under tension Wires connected to movable or shock mounted equipment should have sufficient length to allow full travel without tension on the bundle Wiring at terminal lugs or connectors should have sufficient slack to allow two reterminations without replacement of wires This slack should be in addition to the drip loop and the allowance for movable equipment Normally wire groups or bundles should not exceed 1 2 inch deflection between support
43. and may be installed in the aircraft at the option of the owner Special equipment is any item not corresponding exactly to the descriptive information in the Aircraft Specifications This includes items such as emergency locator transmitter ELT tail or logo lights instruments ashtrays radios navigation lights and carpets Required and optional equipment may be shown on the equipment list with reference to the pertinent item number listed in the applicable specifications only when they are identical to that number item with reference to description weight and arm given in the specifications Show all special equipment items with reference to the item by name make model weight and arm When the arm for such an item is not available determine by actual measurement EQUIPMENT CHANGE The person making an equipment change is obligated to make an entry on the equipment list indicating items added removed or relocated with the date accomplished and identify himself by name and certificate number in the aircraft records Examples of items so affected are the installation of extra fuel tanks seats and baggage compartments Figure 10 15 illustrates the effect on balance when equipment items are added within the acceptable c g limits and fore and aft of the established c g limits 9 8 98 AC 43 13 1B DATUM MAXIMUM BAGGAGE MAXIMUM PASSENGERS MAXIMUM FUEL REARWARD C G LIMIT TO CHECK MOST REARWARD WEIG
44. and the load s imposed by installed electrical power consuming devices Such data should provide a true picture of the status of the electrical system New or additional electrical devices should not be installed in an aircraft nor the capacity changed of any power source until the status of the electrical system in the aircraft has been determined accurately and found not to adversely affect the integrity of the electrical system Page 11 494 and 11 14 9 8 98 JUNCTION BOX CONSTRUCTION Replacement junction boxes should be fabricated using the same material as the original or from a fire resistant nonabsorbent material such as aluminum or an acceptable plastic material Where fire proofing is necessary a stainless steel junction box is recommended Rigid construction will prevent oil canning of the box sides that could result in internal short circuits In all cases drain holes should be provided in the lowest portion of the box Cases of electrical power equipment must be insulated from metallic structure to avoid ground fault related fires See paragraph 11 7 Internal Arrangement The junction box arrangement should permit easy access to any installed items of equipment terminals and wires Where marginal clearances are unavoidable an insulating material should be inserted between current carrying parts and any grounded surface It is not good practice to mount equipment on covers doors of Par 11 3
45. annual inspection is performed on a CAR 3 aircraft with a new interior and there is no mention of a manufacturer s statement that the fabric is flash or flame resistant as applicable the possibility exists that the fabric is an unapproved part The mechanic should take the necessary steps to ensure that the fabric meets or exceeds the ASTM or national standards Refer to 14 CFR part 23 appendix F If an FAA approved STC interior kit is installed in a CAR 3 aircraft and the material and fabric in the kit are PMA or TSO approved the mechanic should include the STC number in block 8 of FAA Form 337 It is recommended that for all CAR 3 interiors to use only fabric and materials that meets the more stringent requirements of part 23 appendix F PART 23 AIRCRAFT INTERIOR Materials used in part 23 aircraft interiors must meet the requirements of section 23 853 and the burn test requirements called out in part 23 appendix F If the fabric is bought in bulk to refurbish a part 23 aircraft then the fabric must meet the part 23 burn requirements A burn test would have to be done on samples of the material and fabrics by an approved and rated FAA Repair Station That FAA Repair Station would certify that all the material and fabrics meet part 23 appendix F requirements The mechanic would include that repair station s statement in the aircraft s records 9 8 98 If STC approved interior kit with either PMA or TSO approved material
46. be specifically designated for the type of fluid in use Care must be taken to ensure that the components installed in the system are compatible with the fluid When gaskets seals and hoses are replaced positive identification should be made to ensure that they are made of the appropriate material Phosphate ester based hydraulic fluids have good solvency properties and may act as plasticizer for certain polymers Care should be taken in handling to keep the fluid from spilling on plastic materials and paint finishes If a small amount of the fluid is spilled during handling it must be cleaned up immediately with a dry cloth When larger quantities are spilled an absorbent sweeping compound is recommended A final cleaning with an approved solvent or detergent should remove any traces of fluid HANDLING HYDRAULIC FLUID In addition to any other instructions provided in the aircraft maintenance manual or by the fluid supplier the following general precautions must be observed in the handling of hydraulic fluids Ensure that each aircraft hydraulic system is properly identified to show the kind of fluid to be used in the Par 9 29 Page 9 424 AC 43 13 1B system Identification at the filler cap or valve must clearly show the type of fluid to be used or added Never allow different categories of hydraulic fluids to become mixed Chemical reactions may occur fire resistant fluids may lose their fire resistance seals may be
47. current through a coil encircling the part being inspected compass a device used to determine direction on the Earth s surface A magnetic compass utilizes the Earth s magnetic field to establish direction compression wood identified by its relatively wide annual rings usually eccentric and its relatively large amount of summer wood usually more than 50 percent of the width of the annual rings in which it occurs Compression wood shrinks excessively lengthwise as compared with normal wood conductor a wire or other material suitable for conducting electricity 618 9 8 98 conduit a rigid metallic or nonmetallic casing or a flexible metallic casing covered with a woven braid or synthetic rubber used to encase electrical cables contact electrical connectors in switch solenoid or relay that controls the flow of current control panel an upright panel open or closed where switches rheostats meters etc are installed for the control and protection of electrical machinery chord an imaginary straight line joining the leading and trailing edges of an airfoil corrosion the electrochemical deterioration of a metal resulting from chemical reaction to the surrounding environment creepage is the conducting of electrical current along a surface between two points at different potentials The current s ability to pass between two points increases with higher voltage and when deposits of moisture
48. damaged etc Never under any circumstances service an aircraft system with a fluid different from that shown on the instruction plate Make certain that hydraulic fluids and fluid containers are protected from contamination of any kind Dirt particles may cause hydraulic units to become inoperative cause seal damage etc If there is any question regarding the cleanliness of the fluid do not use it Containers for hydraulic fluid must never be left open to air longer than necessary Do not expose fluids to high temperature or open flames Mineral based fluids are highly flammable The hydrocarbon based hydraulic fluids are in general safe to handle To work with Material Safety Data Sheets reasonable handling procedures must always be followed Take precaution to avoid fluid getting in the eyes If fluid contacts the eye wash immediately with water 9 8 98 When handling Skydrol Hyjet hydraulic fluids gloves that are impervious to the fluid must be worn If skin contact occurs wash with soap and water When handling phosphate ester based fluid use eye protection If the eye is exposed to fluid severe eye pain will occur When Skydrol Hyjet mist or vapor exposure is possible a respirator capable of removing organic vapors and mists must be worn Ingestion of any hydraulic fluid should be avoided Although small amounts do not appear to be highly hazardous any significant amount should be tested in accordance with
49. electrical wire should be kept to a minimum and avoided entirely in locations subject to extreme vibrations Splicing of individual wires in a group or bundle should have engineering approval and the splice s should be located to allow periodic inspection Many types of aircraft splice connectors are available for use when splicing individual wires Use of a self insulated splice connector is preferred however a noninsulated splice connector may be used provided the splice is covered with plastic sleeving that is secured at both ends Environmentally sealed splices that conform to MIL T 7928 provide a reliable means of splicing in SWAMP areas However a noninsulated splice connector may be used provided the splice is covered with dual wall shrink sleeving of a suitable material Yer d i L 4 eto AC 43 13 1B SPLICING There should not be more than one splice in any one wire segment between any two connectors or other disconnect points except when attaching to the spare pigtail lead of a potted connector to splice multiple wires to a single wire to adjust wire size to fit connector contact crimp barrel size and to make an approved repair Reference MIL W 5088 and NAVAIR 01 1A 505 Splices in bundles must be staggered so as to minimize any increase in the size of the bundle preventing the bundle from fitting into its designated space or cause congestion that will adversely affect maintenance See figure 11
50. facilitate Par 9 43 Page 9 447 AC 43 13 1B determination of the next 12 month inspection period enter the date it is due in the blank beside the word inspect on the inspection data card provided in the inspection data pocket on the cell container Repack close and seal the container REPAIR OF LIFE PRESERVERS Leaks may be disclosed by immersion in soapy water Repair leaks by the use of patches in accordance with the recommendations of the manufacturer Clean corroded metal parts and replace missing or weakened lanyards Life preservers which do not retain sufficient rigidity after the 12 hour period because of general deterioration and porosity of the fabric are beyond economical repair and should be replaced MISCELLANEOUS EQUIPMENT Parachutes With reasonable care parachutes can remain in service indefinitely They should not be carelessly tossed about left in aircraft to become wet or left where someone may tamper with them They should not be placed where they may fall on oily floors or be subject to acid fumes from adjacent battery chargers When repacking is scheduled to comply with the 120 day requirement in Title 14 of the Code of Federal Regulation 14 CFR part 105 section 105 43 a careful inspection of the parachute shall be made by a qualified parachute technician rigger If repairs or replacements of parts are necessary to maintain the airworthiness of the parachute assembly such work must be don
51. fitting on the hub before greasing the hub remove the grease fitting opposite the one to which you are going to add grease This will allow the excess grease and pressure to exit through the grease fitting hole rather than the hub seal Fiber block pitch change mechanisms should be inspected for deterioration fit and the security of the pitch clamp forks Certain models of full feathering propellers use spring loaded pins to retain the feathered blade position Spring and pin units should be cleaned inspected and relubricated per the manufacturer s recommendations and applicable AD s Pitch change counterweights on blade clamps should be inspected for security safety and to ensure that adequate counterweight clearance exists within the spinner TACHOMETER INSPECTION Due to the exceptionally high stresses that may be generated by particular propeller engine combinations at certain engine revolutions per minute RPM many propeller and aircraft manufacturers have established areas of RPM restrictions and other restrictions on maximum RPM for some models Some RPM limits do not exceed 3 percent of the maximum RPM permitted and a slow running tachometer can cause an engine to run past the maximum RPM limits Since there are no post manufacture accuracy requirements for engine tachometers tachometer inaccuracy could lead to propeller failure excessive vibration or unscheduled maintenance If the tachometer exceeds 2 percent plus or minus
52. for a pressure drop check of the system Open the cylinder valve and pressurize the system Observe the pressure gauge a pressure of approximately 1 800 psi at 70 F should be indicated For the light weight ICC 3HT 1850 cylinders pressurize the system to approximately 1 850 psi at 70 F Close the cylinder valve wait approximately 5 minutes for temperatures to stabilize Record the pressure gauge reading and temperature and after 1hour record the pressure gauge reading and temperature again Par 9 50 Page 9 453 AC 43 13 1B A maximum pressure drop of 100psi is permissible NOTE Conduct the above tests in an area where changes of temperature will be less than 10 F If a leak occurs during the 1 hour period suitable corrections would required or reconduct the test under conditions of unvarying temperatures SERVICE REQUIREMENTS OXYGEN CYLINDERS Standard weight cylinders must be hydrostatic tested at the end of each 5 year period This is a Department of Transportation DOT requirement These cylinders carry an ICC or DOT 3AA 1800 classification and are suitable for the use intended The lightweight cylinders must be hydrostatic tested every 3 years and must be retired from service after 24 years or 4 380 pressurizations whichever occurs first These cylinders carry an ICC or DOT 3 HT 1850 classification and must be stamped with the approval after being inspected CAUTION Use only aviatio
53. from the activated ELT antenna the ELT aural tone will be heard see NOTE 2 and 3 Verify That All Switches are Properly Labeled and Positioned Record the Inspection Record the inspection in the aircraft maintenance records according to 14 CFR part 43 section 43 9 We suggest the following I inspected the Make Model ELT system in this aircraft according to applicable Aircraft and ELT manufacturer s instructions and applicable FAA guidance and found that it meets the requirements of section 91 207 d Signed Certificate No Date NOTE 1 This is not a measured check it only indicates that the G switch is working NOTE 2 This is not a measured check but it does provide confidence that the antenna is radiating with sufficient power to aid search and rescue The signal may be weak even if it is picked up by an aircraft VHF receiver located at a considerable distance from the radiating ELT Therefore this check does not check the integrity of the ELT system or provide the same level of confidence as does the AM radio check Par 12 22 AC 43 13 1B NOTE 3 Because the ELT radiates on the emergency frequency the Federal Communications Commission allows these tests only to be conducted within the first five minutes after any hour and is limited in three sweeps of the transmitter audio modulation FLIGHT DATA RECORDER The flight data recorder is housed in a crush proof container located near the tail secti
54. in flight ALTERNATOR DIODES Alternators employ diodes for the purpose of converting the alternating current to direct current These diodes are solid state electronic devices and are easily damaged by rough handling abuse over heating or reversing the battery connections A voltage surge in the line if it exceeds the design value may destroy the diode The best protection against diode destruction by voltage surges is to make certain that the battery is never disconnected from the aircraft s electrical system when the alternator is in operation The battery acts as a large capacitor and tends to damp out voltage surges The battery must never be connected with reversed polarity as this may subject the diodes to a forward bias condition allowing very high current conduction and will generally destroy them instantly STATIC ELECTRICAL POWER CONVERTERS Static power converters employ solid state devices to convert the aircraft s primary electrical source voltage to a different voltage or frequency for the operation of radio and electronic equipment They contain no moving parts with the exception of a cooling fan on some models and are relatively maintenance free Various types are available for AC to DC or AC to AC conversion Location of static converters should be carefully chosen to ensure adequate ventilation for cooling purposes Heat radiating fins should be kept clean of dirt and other foreign matter that may impair
55. indicate an adequate connection Care should be taken in designing such connections to avoid creating continuous current paths that could allow lightning or power fault currents to pass through connections not designed to tolerate these higher amplitude currents without arcing Simulated static charge lightning or fault current tests may be necessary to establish or verify specific designs All other fuel system components such as fuel line line to line access doors fuel line supports structural parts fuel outlets or brackets should have an electromechanical bonding strap secure connector that ensures 1 ohm or less resistance to the structure Advisory Circular 20 53A Protection of Aircraft Fuel Systems Against Fuel Vapor Ignition Due to Lightning and associate manual DOT FAA CT 83 3 provide detailed information on necessary precautions ELECTRIC SHOCK PREVENTION BONDING Electric shock to personnel should be prevented by providing a low resistance path of 1 100 ohm or less between structure and metallic conduits or equipment The allowable ground resistance should be such that the electric potential of the conduit or equipment housing does not reach a dangerous value under probable fault conditions The current carrying capacity of all elements of the ground circuit should be such that under the fault condition no sparking fusion or dangerous heating will occur Metallic supports usually provide adequate bonding if met
56. is determined to a great extent by the cleanliness of the air that flows over the rotor In vacuum systems this air is taken from the cabin where there is usually a good deal of dust and very often tobacco Page 12 614 9 8 98 smoke Unless all of the solid contaminants are removed from the air before it enters the instrument they will accumulate usually in the rotor bearings and slow the rotor This causes an inaccurate indication of the instrument and will definitely shorten its service life Dry air pumps are also subject to damage from REQ D WHEN AIRCRAFT IS PRESSURIZED AC 43 13 1B ingested contaminants and all of the filters in the system must be replaced on the schedule recommended by the aircraft manufacturer and more often if the aircraft is operated under particularly dusty conditions especially if the occupants of the aircraft regularly smoke while flying See figures 12 3 and 12 4 INLINE FILTER eS FIGURE 12 4 Instrument pressure system using a dry type air pump 12 39 12 50 RESERVED Par 12 38 Page 12 615 and 12 18 Par 12 51 9 8 98 AC 43 13 1B SECTION 4 AVIONICS TEST EQUIPMENT GENERAL Certificated individuals who maintain airborne avionics equipment must have test equipment suitable to perform that maintenance TEST EQUIPMENT CALIBRATION STANDARDS The test equipment calibration standards must be derived from and traceable to one of the following The National
57. limit transmitting excessive loads to structures and to the rudder control system It is recommended that the nose steering arc limits be painted on the steering collar or fuselage Inspect shimmy dampers for leakage around the piston shaft and at fluid line connections and for abnormal wear or looseness around the pivot points Also check for proper rigging bottoming of the piston in the cylinder and the condition of the external stops on the steering collar Tail Wheels Disassembly cleaning and re rigging of tail wheels are periodically necessary Inspect them for loose or broken bolts broken springs lack of lubrication and general condition Check steerable tail wheels for proper steering action steering horn wear clearances and for security and condition of steering springs and cables Gear Doors Inspect gear doors frequently for cracks deformation proper rigging and general condition Gear door hinges are especially susceptible to progressive cracking which can ultimately result in complete failure allowing the door to move and cause possible jamming of the gear This condition could also result in the loss of the door during flight In addition check for proper safetying of the hinge pins and for distorted sheared loose or cracked hinge rivets Inspect the wheel wells for improper location or routing of components and related tubing or wiring This could interfere with the travel of the gear door actuating
58. maintaining physical pressure between the various current carrying members of an electrical connection Terminal studs or binding posts should be of a size that is entirely adequate for the current requirements of the equipment and have sufficient mechanical Par 11 176 AC 43 13 1B strength to withstand the torque required to attach the cable to the equipment All terminals on equipment should have barriers and covers provided by equipment manufacturers CRIMP ON TERMINAL LUGS AND SPLICES Pre insulated erimp type Must be installed using a CRIMP ON TERMINAL LUGS AND SPLICES pre insulated crimp type The crimp on terminal lugs and splices must be installed using a high quality ratchet type crimping tool Hand portable and stationary power tools are available for crimping terminal lugs These tools crimp the barrel to the conductor and simultaneously from the insulation support to the wire insulation Crimp tools must be carefully inspected Insure that the full cycle ratchet mechanism is tamper proof so that it cannot be disengaged prior to or during the crimp cycle If the tool does not function or faults are found reject the tool and send the tool to be repaired The tool calibration and adjustments are make only by the manufacturer or an approved calibration laboratory Suitable gages of the Go No type are available and shall be used prior to any crimping operation and whenever possible during
59. means for the operation of aircraft components The operation of landing gear flaps flight control surfaces and brakes is largely accomplished with hydraulic power systems Hydraulic system complexity varies from small aircraft that require fluid only for manual operation of the wheel brakes to large transport aircraft where the systems are large and complex To achieve the necessary redundancy and reliability the system may consist of several subsystems Each subsystem has a power generating device pump reservoir accumulator heat exchanger filtering system etc System operating pressure may vary from a couple hundred psi in small aircraft and rotorcraft to several thousand psi in large transports Generally the larger the aircraft the more mechanical work is required to control the aircraft s various functions Consequently the system operating pressure increases accordingly Primarily hydraulic power is generated by either engine driven or electric motor driven pumps The majority of hydraulic pumps are pressure compensated to provide a constant output pressure at a flow rate demanded by the system Some constant displacement pumps with a relief valve are used on the smaller aircraft PURPOSES OF HYDRAULIC SYSTEMS Hydraulic systems make possible the transmission of pressure and energy at the best weight per horsepower ratio TYPES OF HYDRAULIC FLUID There are three principal categories of hydraulic fluids mineral ba
60. meteorological conditions Any determination of airworthiness after reinstallation before instrument flight must be accomplished with ground test equipment Par 12 10 Page 12 604 AC 43 13 1B The glide slope receiver operates on one of 40 channels within the frequency range 329 15 MHz to 335 00 MHz The glide slope transmitter is located between 750 feet and 1250 feet from the approach end of the runway and offset 250 to 650 feet In the absence of questionable performance periodic functional flight checks of the glide slope system would be an acceptable way to ensure continued system performance The functional flight test must be conducted under visual flight rules VFR conditions A failed or misleading system must be serviced by an appropriately rated repair station Ground test equipment can be used to verify glide slope operation Localizer Glide Slope LOC GS may have self test function otherwise the proper ground test equipment must be used Refer to manufacturer s or aircraft instruction manual MARKER BEACON Marker beacon receivers operate at 75 MHz and sense the audio signature of each of the three types of beacons The marker beacon receiver is not tunable The blue outer marker light illuminates when the receiver acquires a 75 MHz signal modulated with 400 Hz an amber middle marker light for a 75 MHz signal modulated with 1300 Hz and a white inner marker light for a 75 MHz signal modulated with 3000 Hz The
61. of breakage between the contact and wire due to vibration Connectors specifically designed for potting compounds should be potted to provide environment resistance An o ring or sealed gasket should be included to seal the interface area of the mated connector A plastic potting mold that remains on the connector after the potting compounds have cured should also be considered To facilitate circuit changes spare wires may be installed to all unused contacts prior to filling the connector with potting compound Connect wires to all contacts of the connector prior to the application of the potting compound Wires that are not to be used should be long enough to permit splicing at a later date Unused wires should be as shown in figure 11 38 and the cut ends capped with heat shrinkable caps or crimped insulated end caps such as the MS 25274 prior to securing to AC 43 13 1B the wire bundle Clean the areas to be potted with dry solvent and complete the potting operation within 2hours after this cleaning Allow the potting compound to cure for 24 hours at a room temperature of 70 F to 75 F or carefully placed in a drying oven at 100 F for 3 to 4 hours In all cases follow manufacturer s instructions THROUGH BOLTS Through bolts are sometimes used to make feeder connections through bulkheads fuselage skin or firewalls Mounting plates for through bolts must be a material that provides the necessary fire barrier insulation
62. of each system The filter rating is given in terms of micron and is an indication of the particle size that will be filtered out The replacement interval of these filters is established by the manufacturer and is included in the maintenance manual However in the absence of specific replacement instructions a recommended service life of the filter elements is Pressure filters 3000 hrs Par 9 28 Page 9 425 AC 43 13 1B Return Filters 1500 hrs Case drain filters 600 hrs When replacing filter elements be sure that there is no pressure on the filter bowl Protective clothing and a face shield must be used to prevent fluid from contacting the eye Replace the element with one that has the proper rating After the filter element has been replaced the system must be pressure tested to ensure that the sealing element in the filter assembly is intact In the event of a major component failure such as a pump consideration must be given to replacing the system filter elements as well as the failed component System filters may also be equipped with differential pressure AP indicators These indicators are designed to pop up when the pressure drop across the element reaches a predetermined value caused by contamination held by the element The indicators are designed to prevent false indications due to cold start pump ripple and shock loads Consequently a filter whose indicator has been activated must b
63. of landing gear doors should be checked Improper adjustment of sequence valves may cause doors to rub against gear structures or wheels The manufacturer s checklist should be followed to ensure that critical items are checked While the aircraft is still on jacks the gear can be tested for looseness of mounting points play in torque links condition of the inner strut cylinder play in wheel bearings and play in actuating linkages Emergency blow down gear bottles should be inspected for Par 9 4 Page 9 412 AC 43 13 1B damage and corrosion and weighed to see if the bottle is still retaining the charge Mechanics should be aware that retread tires can be dimensionally bigger than a new tire While this does not pose a problem on fixed landing gear aircraft it may present a serious problem when installed on retractable landing gear aircraft It is strongly recommended that if a retread tire is installed on a retractable landing gear aircraft a retraction test be performed With the gear in the up and lock position the mechanic should determine that if the tire expands due to high ambient temperature heat generated from taxi and take off repeated landings or heavy braking the tire will not expand to the point that it becomes wedged in the wheel well The proper operation of the anti retraction system should be checked in accordance with the manufacturer s instructions Where safety switches are actuated by the torq
64. operation to ensure crimp dimensions For further information refer to MIL C 22520 Crimping Tools Hand or Power Actuated Wire Termination and Tool Kits This specification covers in detail the general requirements for crimp tools inspection gages and tool kits Page 11 549 9 8 98 AC 43 13 1B LOCK WASHERS FOR TERMINALS ON EQUIPMENT Where locknuts are used to ensure binding and locking of electrical terminals they should be of the all metal type In addition a spring lock washer of suitable thickness may be installed under the nut to ensure good contact pressure A plain washer should be used between the spring washer and the terminal to prevent galling A plain nut with a spring lock washer and a plain washer may be used to provide binding and contact pressure 11 180 11 184 RESERVED Par 11 185 Page 11 550 Par 11 185 9 8 98 AC 43 13 1B SECTION 15 GROUNDING AND BONDING GENERAL One of the more important factors in the design and maintenance of aircraft electrical systems is proper bonding and grounding Inadequate bonding or grounding can lead to unreliable operation of systems e g EMI electrostatic discharge damage to sensitive electronics personnel shock hazard or damage from lightning strike This section provides an overview of the principles involved in the design and maintenance of electrical bonding and grounding SAE ARP 1870 provides for more complete detailed information on grounding and b
65. or as support for personal equipment or where they could become damaged during removal of aircraft equipment Wiring must be clamped so that contact with equipment and structure is avoided Where this cannot be accomplished extra protection in the form of grommets chafe strips etc should be provided Protective grommets must be used wherever wires cannot be clamped in a way that ensures at least a 3 8 inch clearance from structure at penetrations Wire must not have a preload against the corners or edges of chafing strips or grommets Wiring must be routed away from high temperature equipment and lines to prevent deterioration of insulation Protective flexible conduits should be made of a material and design that eliminates the potential of chafing between their internal wiring and the conduit internal walls Wiring that must be routed across hinged panels must be routed and clamped so that the bundle will twist rather than bend when the panel is moved GROUP AND BUNDLE TIES A wire bundle consists of a quantity of wires fastened or secured together and all traveling in the same direction Wire bundles may consist of two or more groups of wires It is often advantageous to have a number of wire groups individually tied within the wire bundle for ease of identification at a later date See figure 11 7 Comb the wire groups and bundles so that the wires will lie parallel to each other and minimize the possibility of insulation
66. or other conductive materials exist on the surfaces cross grain grain not parallel with the axis of a piece It may be either diagonal or spiral grain or a combination of the two cross coat a double coat of dope or paint It is sprayed on in one direction and then immediately after the solvent flash off it is sprayed at right angles to the first coat cure to change the properties of a thermosetting resin irreversibly by vulcanization or chemical reaction May be accomplished by the addition of curing cross linking agents with or without a catalyst and with or without heat or pressure curing temperature temperature to which a resin or an assembly is subjected in order to cure the resin cutting torch a device used in gas cutting of metals damping iimiting the duration of vibration by either electrical or mechanical means AC 43 13 1B Appendix 1 data information that supports and or describes the original aircraft design alteration or repair including the following 1 drawings sketches and or photographs 2 engineering analysis 3 engineering orders and 4 operating limitations datum imaginary vertical plane from which all horizontal measurements are made or indicated when the aircraft is in level flight attitude derating is a technique whereby a part is stressed in actual usage at values well below the manufacturer s rating for the part By decreasing mechanical thermal and electr
67. pads Indicate these points clearly in the weight and balance report when used instead of the landing gear Typical locations of the weighing points are shown in figure 10 8 Zero Fuel Weight The maximum permissible weight of a loaded aircraft passengers crew cargo etc less its fuel is zero fuel weight All weights in excess of maximum zero fuel weight must consist of usable fuel The minimum fuel for balance 1 12 gallon per maximum Minimum Fuel purposes is Par 10 2 Page 10 465 OPERATIONS except take off horsepower Minimum fuel is the maximum amount of fuel which can be used in weight and balance computations when low fuel might adversely affect the most critical balance conditions To determine the weight of fuel in pounds divide the METO horsepower by two Full Oil The full oil is the quantity of oil shown in the Aircraft Specifications or TCDS as oil capacity Use full oil as the quantity of oil when making the loaded weight and balance computations Tare The weight of chocks blocks stands etc used when weighing aircraft is called tare and is included in the scale readings Tare is deducted from the scale reading at each respective weighing point when tare is involved to obtain the actual aircraft weight 9 8 98 AC 43 13 1B WEIGHING POINT MAIN WHEEL SCALE WEIGHING POINT k TAIL WHEEL WEIGHING POINT NOSE WHEEL WEIGHING POINT JACKPAD
68. procedures for handling equipment containing electrostatic sensitive devices or assemblies in accordance with the recommendations and procedures set forth in the maintenance instructions set forth by the equipment manufacturers 12 3 12 7 RESERVED Page 12 600 and 12 2 Par 12 8 9 8 98 AC 43 13 1B SECTION 2 GROUND OPERATIONAL CHECKS FOR AVIONICS EQUIPMENT ELECTRICAL GENERAL When the operating or airworthiness regulations require a system to perform its intended function the use of the Technical Standard Order TSO equipment or the submission of data substantiating the equipment performance is strongly recommended An operation check of avionics is the responsibility of the pilot in command However it is recommended that after replacement of equipment during 100 hour or annual inspections an operational check of avionics equipment be performed The accomplishments of these checks must be done in accordance with the recommendations and procedures set forth in the aircraft s flight manual instructions published by the avionics equipment manufacturers INSPECTION OF AVIONICS SYSTEMS The inspection shall include the following Inspect the condition security of equipment including the proper security of wiring bundles Check for indications of overheating of the equipment and associated wiring Check for poor electrical bonding The bonding requirements are specified by equipment manufactur
69. quick disconnect plugs and pins for evidence of corrosion pitting arcing and burns Clean as required Inspect battery drain and vent lines for restriction deterioration and security Routine pre flight and post flight inspection procedures should include observation for evidence of physical damage loose connections and electrolyte loss ELECTROLYTE SPILLAGE Spillage or leakage of electrolyte may result in serious corrosion of the nearby structure or control elements as both sulfuric acid and potassium hydroxide are actively corrosive Electrolyte may be spilled during ground servicing leaked when cell case rupture occurs or sprayed from cell vents due to excessive charging rates If the battery is not case enclosed properly treat structural parts near the battery that may be affected by acid fumes Treat all case and drain surfaces that have been affected by electrolyte with a solution of sodium bicarbonate for acid electrolyte or boric acid vinegar or a 3 percent solution of acetic acid for potassium hydroxide electrolyte CAUTION Serious burns will result if the electrolyte comes in contact with any part of the body Use rubber gloves rubber apron and protective goggles when handling electrolyte If sulfuric acid is splashed on the body Page 11 489 9 8 98 neutralize with a solution of baking soda and water and shower or flush the affected area with water For the eyes use an eye fountain and flush
70. repair and modification of existing aircraft when a replacement wire is required the maintenance manual for that aircraft must first be reviewed to determine if the original aircraft manufacturer OAM has approved any substitution If not then the OAM must be contacted for an acceptable replacement MIL W 5088L Wiring Aerospace Vehicle Appendix A lists wire types that have been approved for military aerospace applications in open and protected wiring applications These wires could potentially be used for substitution when approved by the OAM Areas designated as severe wind and moisture problem SW AMD areas differ Page 11 518 and 11 38 9 8 98 from aircraft to aircraft but generally are considered to be areas such as wheel wells near wing flaps wing folds pylons and other exterior areas that may have a harsh environment Wires for these applications often have design features incorporated into their construction that may make the wire unique therefore an acceptable substitution may be difficult if not impossible to find It is very important to use the wire type recommended in the aircraft manufacturer s maintenance handbook The use of current military specification multi conductor cables in place of OEM installed constructions may create problems such as color sequence Some civilian aircraft Par 11 78 AC 43 13 1B are wired with the older color sequence employing Red Blue Yellow as the first thre
71. some typical examples Resistance Calculation Methods Figures 11 2 and 11 3 provide a convenient means of calculating maximum wire length for the given circuit current Values in tables 11 7 11 8 are for tin plated copper conductor wires Because the resistance of tin plated wire is slightly higher than that of nickel or silver plated wire maximum run lengths determined from these charts will be slightly less than the allowable limits for nickel or silver plated copper wire and are therefore safe to use Figures 11 2 and 11 3 can be used to derive slightly longer maximum run lengths for silver or nickel plated wires by multiplying the maximum run length by the ratio of resistance of tin plated wire divided by the resistance of silver or nickel plated wire 100 ft 20 amps 89 volts 000183 ohms ft 50 ft 40 amps 366 volts 4 volt 100 feet 00202 9 8 98 7 volt 100 feet 20 amps See Note 1 No 14 ohms ft 100 ft 20 amps 4 04 volts 00304 ohms ft 100 ft 20 amps 6 12 volts Note 1 14 Wire should be routed separately for this current rating TABLE 11 8 Examples of determining maximum run length using figure 11 3 Maximum Wire Run Length Circuit Current Maximum Voltage drop 39 feet 19 5 feet 156 feet 273 feet Par 11 66 Check calculated voltage drop Resistance Ft Length Current 00126 ohms ft 39 ft 20 amps 9
72. steady state condition equal to the rated temperature of the wire should not be exceeded Rated temperature of the wire may be based upon the ability of either the conductor or the insulation to withstand continuous operation without degradation Single Wire in Free Air Determining a wiring system s current carrying capacity begins with determining the maximum current that a given sized wire can carry without exceeding the allowable temperature difference wire rating minus ambient C The curves are based upon a single copper wire in free air See figures 11 4a and 11 4b Wires in a Harness When wires are bundled into harnesses the current derived for a single wire must be reduced as shown in figure 11 5 The amount of current derating is a function of the number of wires in the bundle and the percentage of the total wire bundle capacity that is being used 9 8 98 Harness at Altitude Since heat loss from the bundle is reduced with increased altitude the amount of current should be de rated Figure 11 6 gives a curve whereby the altitude derating factor may be obtained Aluminum Conductor Wire When aluminum conductor wire is used sizes should be selected on the basis of current ratings shown in table 11 10 The use of sizes smaller than 8 is discouraged Aluminum wire should not be attached to engine mounted accessories or used in areas having corrosive fumes severe vibration mechanical stresses or where there is a ne
73. temperature and by using a filler metal having a liquidus not exceeding 450 C 840 F and below the solidus of the base metals The filler metal is distributed between the closely fitted surfaces of the joint by capillary action solenoid a tubular coil for the production of a magnetic field electromagnet with a core which is able to move in and out spar main spanwise structural member s of an aircraft wing or rotorcraft rotor A wing may have one or two made into a single strong box to which secondary leading and trailing structures are added spiral grain a type of growth in wood which the fibers take a spiral course about the bole of a tree instead of the normal vertical course The spiral may extend right handed or left handed around the tree trunk stator the part of an AC generator or motor which contains the stationary winding stress corrosion corrosion of the intergranular type that forms within metals subject to tensile stresses which tend to separate the grain boundaries surface tape pinked edge strips of fabric doped over all seams rib stitching and edges of fabric covering also called finishing tape switch a device for opening or closing an electrical circuit 624 9 8 98 tape a tape or a narrow fabric is loosely defined as a material that ranges in width from 1 4 inch to 12 inches TCAS traffic alert and collision avoidance system An airborne system that interrogate
74. the actual circuit current for each wire in the bundle and for the whole bundle If the values calculated in step 5 are exceeded select the next larger size wire and repeat the calculations Example 2 Assume a harness open or braided consisting of 12 size 12 200 C rated copper wires will be operated in an ambient of 25 C at sea level and 60 C at a 20 000 foot altitude All 12 wires will be operated at or near their maximum capacity Page 11 514 9 8 98 AC 43 13 1B STEP 1 Refer to the single wire in free air curve in figure 11 4a determine the temperature difference of the wire to determine free air ratings Since the wire will be in ambient of 25 C and 60 C and is rated at 200 C the temperature differences are 200 C 25 C 175 C and 200 C 60 C 140 C respectively Follow the 175 C and the 140 C temperature difference lines on figure 11 4a until each intersects wire size line the free air ratings of size 12 are 68 amps and 61 amps respectively STEP 2 Refer to the bundling derating curves in figure 11 5 the 100 percent curve is selected because we know all 12 wires will be carrying full load Find 12 on the abscissa since there are 12 wires in the bundle and determine a derating factor of 0 43 on the ordinate from the 100 percent curve STEP 3 Derate the size 12 free air ratings by multiplying 68 amps and 61 amps by 0 43 to get 29 2 amps and 26 2 amps respectively Par 11 76 Pa
75. the fuel system until the quantity indicator reads zero or until the tanks are empty with the aircraft in level flight attitude unless otherwise noted in the TCDS or Aircraft Specifications amount of fuel remaining in the tank lines and engine is termed residual fuel and is to be included in the empty weight In special cases the aircraft may be weighed with full fuel in tanks provided a definite means of determining the exact weight of the fuel is available The oil system should be filled to the quantity noted in the TCDS or Aircraft Specifications NOTE On Civil Aeronautics Regulations CAR 3 Certified Aircraft the weight of the oil was subtracted mathematically to get the empty weight In 14 CFR part 23 aircraft the weight of the oil was included in the empty weight Do not set brakes while taking scale reading Note any tare reading when the aircraft is removed from the scales WEIGHT AND BALANCE COMPUTATIONS It is often necessary after completing an extensive alteration to establish by computation that the authorized weight and c g limits as shown in the TCDS and Aircraft Specifications are not exceeded Paragraph b 2 explains the significance of algebraic signs used in balance computations 9 8 98 AC 43 13 1B paa DATUM Cr o OIL TANK 9 QTS ne WEIGHT OF AIRCRAFT WITH OIL IS 1186 LBS EMPTY WEIGHT AND EMPTY WEIGHT CENTER OF GRAVITY when aircraft is weighed with oil GIVEN Aircraft as
76. tin plated conductor area 105 C 150 C 200 C See Note 2 circ mils Note 1 Rating is for 70 C ambient 33 or more wires in the bundle for sizes 24 through 10 and 9 wires for size 8 and larger with no more than 20 percent of harness current carrying capacity being used at an operating altitude of 60 000 feet For rating of wires under other conditions or configurations see paragraph 11 69 Note 2 For resistance of silver or nickel plated conductors see wire specifications TABLE 11 10 Current carrying capacity and resistance of aluminum wire Continuous duty current amps Wire Size Wires in bundles groups or harnesses Max resistance or conduits See table 11 9 Note 1 ohms 1000ft Wire conductor temperature rating 20 C Note Observe design practices described in paragraph 11 67 for aluminum conductor Par 11 66 Page 11 506 9 8 98 Approximate T2 can be estimated using the following formula T T Te T Tus Where Ti Ambient Temperature Estimated Conductor Temperature Tr Conductor Temperature Rating Circuit Current A Amps LI Maximum Allowable Current A Amps at Tr This formula is quite conservative and will typically yield somewhat higher estimated temperatures than are likely to be encountered under actual operating conditions METHODS FOR DETERMINING CURRENT CARRYING CAPACITY OF WIRES This paragraph contains methods for determining the current carrying ca
77. vibration and stress to the airframe and engine and may cause premature propeller failure Page 8 407 VIBRATION Although vibration can be caused by the propeller there are numerous other possible sources of vibration which can make troubleshooting difficult If a propeller vibrates whether due to balance angle or track problems it typically vibrates throughout the entire RPM range although the intensity of the vibration may vary with the RPM If a vibration occurs only at one particular RPM or within a limited RPM range e g 2200 2350 RPM the vibration is not normally a propeller problem but a problem with a poor engine propeller match If a propeller vibration is suspected but cannot be positively determined if possible the ideal troubleshooting method is to temporarily replace the propeller with one which is known to be airworthy and test fly the aircraft There are numerous allowable tolerances in blade angles balance track and blade width and thickness dimensions These tolerances have been established through many years of experience The degree to which these factors affect vibration is sometimes disputed and can involve significant repair bills which may or may not cure a vibration problem Reliance upon experienced reputable propeller repair stations is the owner s best method of dealing with these problems Blade shake is not the source of vibration problems Once the engine is running centrifugal force h
78. voltage regulation problems Likewise repeated localized material heating by current surges can cause material degradation Both problems may occur without warning and cause nonrepeatable failures or anomalies Common Ground Connections The use of common ground connections for more than one circuit or function should be avoided except where it can be shown that related malfunctions that could affect more than one circuit will not result in a hazardous condition Par 11 185 AC 43 13 1B Even when the loss of multiple systems does not in itself create a hazard the effect of such failure can be quite distracting to the crew Redundant systems are normally provided with the objective of assuring continued safe operation in the event of failure of a single channel and must therefore be grounded at well separated points To avoid construction or maintenance errors that result in connecting such ground at a single point wires that ground one channel of a redundant system should be incapable of reaching the ground attachment of the other channel The use of loop type grounding systems several ground leads connected in series with a ground to structure at each end must be avoided on redundant systems because the loss of either ground path will remain undetected leaving both systems with a potential single point failure Electrical power sources must be grounded at separate locations on the aircraft structure The loss of multi
79. weighed with full oil 1186 Ibs Center of gravity 9 7 Full oil capacity 9 17 Ibs SOLVING Weight x Amr Moment Aircraft as weighed 1186 11504 Lesol dor 49 0 8933 69 s 13378 Empty Weight A 2 1169 pounds Empty Weight Center of Gravity 12337 10 6 2B A 1169 FIGURE 10 9 Empty weight and empty weight center of gravity when aircraft is weighed with oil The TCDS or Aircraft Specifications contain the Maximum baggage and arm following information relating to the subject e Fuel capacity and arm e Oil capacity and arm e Center of gravity range e Equipment items and arm e Empty weight c g range when applicable e Leveling means The TCDS do not list the basic required equipment e Datum prescribed by the applicable airworthiness regulations e Maximum weights for certification Refer to the manufacturer s equipment e Number of seats and arm list for such information Par 10 14 Page 10 468 9 8 98 Unit weight for weight and balance purposes Gasoline 6 pounds per U S gal Turbine Fuel 6 7 pounds per U S gal Lubricating oil 7 5 pounds U S gal Crew and passengers 170 pounds per person It is important to re
80. with the surface of the piece fluorescent a substance is said to be fluorescent when it will glow or fluoresce when excited by ultraviolet light Some types of dye penetrant material use fluorescent dyes which are pulled from the cracks by a developer and observed under black ultraviolet light flux materials used to prevent dissolve or facilitate removal of oxides and other undesirable surface substances Also the name for magnetic fields fretting corrosion corrosion damage between close fitting parts which are allowed to rub together The rubbing prevents the formation of protective oxide films and allows the metals to corrode fuse a protective device containing a special wire that melts when current exceeds the rated value for a definite period functional check this test may require the use of appropriate test equipment galvanic corrosion corrosion due to the presence of dissimilar metals in contact with each other gas cylinder a portable container used for transportation and storage of a compressed gas AC 43 13 1B Appendix 1 gas tungsten arc welding GTAW an arc welding process which produces coalescence of metals by heating them with an arc between a tungsten nonconsumable electrode and the work Shielding is obtained from a gas or gas mixture Pressure may or may not be used and filler metal may or may not be used generator a device for converting mechanical energy into electr
81. within manufacturer s limits The following two examples show how to determine the allowable repair limits on aluminum alloy blades Par 8 73 Page 8 397 Example 1 Determine the blade width repair allowable Aw and minimum blade width limit for a blade having a diameter d of 10 ft 6 in The repair location 9 8 98 ri is 24 in from the shank and the original as manufactured blade width w at the repair location is 1 88 in Step 1 Calculate the blade radius r z o o 3 a e 2 o a o o 9 r E a z x r E Q s 2 2 a r4 E AH AC 43 13 1B r d 2 10 ft 6 in 2 126 2 63 in Step 2 Calculate percent of blade radius to repair r r rlr x 100 24 63 x 100 38 REDUCTIONS SHOWN ARE THE MAXIMUM ALLOWABLE BELOW THE MINIMUM DIMENSIONS REQUIRED BY THE BLADE DRAWING AND BLADE RESP RADIUS PERCENT OF REPAIRED BLADE RADIUS a Draw a vertical line at the value of r 38 on the horizontal axis b Where the vertical line intersects the curve draw a horizontal line to the right to intersect the vertical axis c Read the percent reduction in width Aw on the vertical axis at this intersection Aw 2 5 IGURE 8 27 Example 1 Determine the repair width limits Step 3 Determine percent reduction in width Aw from figure 8 27 Step 4 Calculate the blade widt
82. 215A20 WHITE H246A20 BLUE H217A20 ORANGE a Multiple wires in a sleeve FIGURE 11 23 Spacing of printed identification marks direct marking ar 11 205 Page 116563 9 8 98 FIGURE 11 24 Spacing of printed identification marks indirect marking Par 11 205 Page 11 564 AC 43 13 1B Alternative identification methods such as Laser Printing Ink Jet and Dot Matrix are preferred When such modern equipment is not available the use of stamped identification sleeving should be considered on insulation wall thickness of 10 mils or less HOT STAMP MARKING This method imprints hot ink marks onto the wire Caution must be exercised when using this method as it has been shown to damage insulation when incorrectly applied Type set characters similar to that used in printing presses but shaped to the contour of the wire are heated to the desired temperature Wire is pulled through a channel directly underneath the characters The heat of the type set characters transfers the ink from the marking foil onto the wire Good marking is obtained only by the proper combination of temperature pressure and dwelling Hot stamp will mark wire with an outside diameter of 0 038 to 0 25 inch 9 8 98 Before producing hot stamp wire it must be assured that the marking machine is properly adjusted to provide the best wire marking with the least wire insulation deterioration The marking should never cre
83. 29 data bus standard 629 ARINC 629 data bus standard A D analog digital analog to digital A D CONV analog to digital converter A L autoland AC Advisory Circular ac alternating current ACARS ARINC Communication Addressing and Reporting System ACO Aircraft Certification Office AD Airworthiness Directive ADC air data computer ADCP ATC dual control panel ADEDS advanced electronic display system ADF automatic direction finder ADI attitude director indicator air data instrument AFC automatic frequency control AFCS automatic flight control system AFDS autopilot flight detector system AIM Aeronautical Information Manual AIRCOM air ground communications M amplitude modulation MP or AMPL amplifier MP amperes MS Aerospace Material Specification N Army Navy ND Army Navy Design NSI A me rican National Standards Institute NT antenna AP autopilot APB auxiliary power breaker APCU auxiliary power control unit APU auxiliary power unit ARINC Aeronautical Radio Incorporated ARNC IO ARINC I O error ARNC STP ARINC I O UART data strip error ASTM American Society for Testing Materials ATA Air Transport Association ATC air traffic control ATCT ATC transponder ATCTS ATC transponder system AUX auxiliary AVC automatic volume control AWG American Wire Gauge gt gt p gt p gt yy AWS Air Weather Service B C
84. 4 TYPICAL LANDIN GEAR FITTING CRACKS FIGURE 9 3 Typical cracks near bolt holes 9 8 98 FIGURE 9 4 Typical bolt hole cracks The usual types of failure in riveted joints or seams are deformation of the rivet heads and skin cracks originating at the rivets holes Cracks and subsequent failures of rod ends usually begin at the thread end near the bearing and adjacent to or under the jam nut See figure 9 5 FIGURE 9 5 Typical rod end cracks Cracks develop primarily along the edge of the weld adjacent to the base metal and along the centerline of the bead Elongated holes are especially prevalent in taper pin holes and bolt holes or at the riveted joints of torque tubes and push pull rods See figure 9 6 FIGURE 9 6 Typical torque tube bolt hole elongation Par 9 11 Page 9 418 AC 43 13 1B Deformation is common in rods and tubes and usually is noticeable as stretched bulged or bent sections As deformations of this type are difficult to see feel along the tube for evidence of this discrepancy Deformation of sheet metal web sections at landing gear component attachment points usually can be seen when the area is highlighted with oblique lighting SPECIAL INSPECTIONS Any time an aircraft has experienced a hard or overweight landing it is recommended that a special structural inspection which includes the landing gear be performed Typical areas which require special attention are
85. 8 9 8 98 the stud Therefore loosening of the insulation support of the stud will not affect the electric contact efficiency In other words the contact pressure on the wire lugs should not in any way be affected by the loosening of the stud in the insulator Support of Wire at Studs Unless some other positive locking action is provided the lug or wire should be supported next to the stud to prevent loosening the connection with a side pull on the wire Torque recommendations for attaching electrical wiring devices to terminal boards or blocks studs posts etc are normally found in the manufacturer s maintenance instruction manual Feed Through Insulator and Stud Design Feed through insulator design should be such as to prevent a loose insulator from failing to provide circuit isolation It should not be able to move from between the stud and the structure thus allowing the two to come into contact The assembly should be so designed that it is impossible to inadvertently misassemble the parts so that faults will result Also it is desirable to provide means to prevent the feed through stud from turning while tightening the connection WIRE TERMINALS AND BINDING POSTS All wire terminals in or on electrical equipment except case ground must be firmly held together with two nuts or suitable locking provisions or should be secured in a positive manner to equipment in such a way that no insulation material is involved in
86. 8 AC 43 13 1B junction boxes since inspection for internal clearance is impossible when the door or cover is in the closed position Installation Junction boxes should be securely mounted to the aircraft structure in such a manner that the contents are readily accessible for inspection When possible the open side should face downward or at an angle so that loose metallic objects such as washers or nuts will tend to fall out of the junction box rather than wedge between terminals Wiring Junction box layouts should take into consideration the necessity for adequate wiring space and possible future additions Electrical wire bundles should be laced or clamped inside the box so that cables do not touch other components prevent ready access or obscure markings or labels Cables at entrance openings should be protected against chafing by using grommets or other suitable means 11 39 11 46 RESERVED Page 11 495 and 11 14 Par 11 47 9 8 98 AC 43 13 1B SECTION 4 INSPECTION OF CIRCUIT PROTECTION DEVICES GENERAL All electrical wires must be provided with some means of circuit protection Electrical wire should be protected with circuit breakers or fuses located as close as possible to the electrical power source bus Normally the manufacturer of electrical equipment will specify the fuse or breaker to be used when installing the respective equipment or SAE publication ARP 1199 may be referred to for recommen
87. 8 98 AC 43 13 1B TIN C e SSS TEMPERATURE DIFFERENCE 2 a T o o 5 R 40 50 60 70 80 90100 300 400 50 600 CURRENT AMPERES FIGURE 11 4b Single copper wire in free air The size 14 wire selected using the methods outlined in paragraph 11 66d is too small to meet the voltage drop limits from figure 11 2 for a 15 feet long wire run STEP 3 Select the next larger wire size 12 and repeat the calculations as follows L 24 feet maximum run length for 12 gauge wire carrying 20 amps from figure 11 2 Imax 34 4 amps this is the maximum current the size 12 wire can carry at 50 C ambient using calculation methods outlined in paragraph 11 69 Par 11 68 50 C 200 C 50 C W20A 34 4 50 C 150 C 762 2164 4 C 2545 CL 27 09459 CD Qs45 C QMf gt 234 5 C 164 4 C 254 5 C Aft 153f 2 398 9 n Page 11 511 9 8 98 AC 43 13 1B 15 7 19 21 23 13 z e N Ha m m Z YOLOVA DNILV3HG FIGURE 11 5 Bundle derating curves Par 11 68 Page 11 512 9 8 98 AC 43 13 1B YOLOVA ONILVAAC FIGURE 11 6 Altitude derating curve Par 11
88. 8 volts 00126 ohms ft 19 5 ft 20 amps 366 volts 00126 ohms ft 156 ft 20 amps 3 93 volts 00126 ohms ft 273 ft 20 amps 6 88 volts AC 43 13 1B As an alternative method or a means of checking results from figure 11 2 resistance for a given wire size can be read from table 11 9 and multiplied by wire run length and circuit current Voltage drop calculations for aluminum wires can be accomplished by multiplying the resistance for a given wire size defined in table 11 10 by the wire run length and circuit current When the estimated or measured conductor temperature T2 exceeds 20 C such as in areas having elevated ambient temperatures or in fully loaded power feed wires the maximum allowable run length L2 must be shortened from L1 the 20 C value using the following formula for copper conductor wire 254 5 C Li 2845 C T For aluminum conductor wire the formula is _ Q58 I OY L 238 1 These formulas use the reciprocal of each material s resistivity temperature coefficient to take into account increased conductor resistance resulting from operation at elevated temperatures To determine 2 for wires carrying a high percentage of their current carrying capability at elevated temperatures laboratory testing using a load bank and a high temperature chamber is recommended Such tests should be run at anticipated worse case ambient tem
89. 9 8 98 AC 43 13 1B CROSS SECTION CROSS SECTION BEFORE REPAIR AFTER REPAIR BEFORE REPAIR em fluo C ee f Wa SURFACE ZA Mz REPAIR BEFORE REPAIR CRACK WORKED OUT FIGURE 8 24 Method of repairing surface cracks nicks etc on aluminum alloy propellers MAXIMUM THICKNESS OF BLADE SECTION IS AT A POINT APPROX IMATELY 3 OF CORD LENTH AS SHOWN 3 OF CHORD LENGTH CORRECT METHOD ORIGINAL SECTION DON NOT DESTROY MAXIMUM THICKNESS O SECTION IF POSSIBLE NOTE DAMAGED A MAINTAIN ORIGINAL RADIUS PORTION B REWORK CONTOUR TO POINT OF MAXIMUM THICKNESS C RADIUS IS TOO LARGE D CONTOUR IS TOO BLUNT INCORRECT METHOD FIGURE 8 25 Correct and incorrect method of reworking leading edge of aluminum alloy propellers Par 8 71 Page 8 396 9 8 98 90 percent blade radius point the blade width and thickness may be modified as per the manufacturer s instructions Shortening Blades Shortening propeller blades is a major repair When the removal or treatment of defects on the tip necessitates shortening a blade shorten each blade used with it and keep such sets of blades together See figure 8 26 for acceptable methods Mark the shortened blades to correspond with the manufacturer s system of model designation to indicate propeller diameter In making the repair it is not permissible to reduce the propeller diameter below the minimum diameter limit shown on the pertinent spe
90. 99 nautical mile NM at the high end of the controlled airspace with an accuracy of 1 2 mile or 3 percent of the distance DME inspection maintenance on the aircraft is most commonly limited to a visual check of the installation and if there have been previously reported problems the antenna must be inspected for proper bonding and the absence of corrosion both on the mounting surface as well as the coax connector Accuracy can be determined by evaluating performance during flight operations as well as with ground test equipment If a discrepancy is reported and corrected it is good practice to make the accuracy determination before instrument flight Tune the DME to a local station or use the proper ground test equipment to check audio identification and DME hold function verify correct display operation AUTOMATIC DIRECTION FINDER ADF The ADF receivers are primarily designed to receive nondirectional beacons NDB in the 19 to 535 kHz amplitude modulation AM broadcast low band The receivers will also operate in the commercial AM band The ADF display pointer will indicate the relative bearing to a selected AM band transmitter that is in range An ADF system must be checked by tuning to an adequate NDB or commercial AM station Verify 9 8 98 proper bearing to station audio identification and tone beat frequency oscillator BFO correct operation in closed circuit LOOP and sense modes Note the orientation of the sel
91. ALE 609 LBS TARE 5 LBS WEIGHING POIN D MEASURED NOSE WHEEL WEIGHING POINT MAIN WHEEL L MEASURE TO FIND EMPTY WEIGHT AND EMPTY WEIGHT CENTER OF GRAVITY Datum is the leading edge of the wing from aircraft specification D Actual measured horizontal distance from the main wheel weighing point p main wheel to the Datum L Actual measured horizontal distance from the front wheel weighing point front wheel to the main wheel weighing point SOLVING EMPTY WEIGHT Poir 5 604 5 615 10 454 mpn ant Vv 1673 SOLVING EMPTY WEIGHT CENTER OF GRAVITY a F x L 454 x 67 8 1 Formula C G 2 D WwW 3 1673 34 18 3 15 7 Reference for formula Figure 10 4 FIGURE 10 6 Empty weight and empty weight center of gravity nosewheel type aircraft Par 10 2 Page 10 464 9 8 98 AC 43 13 1B C G RANGE THE LOADED C G MUST BE yy WITHIN THE LIMITS SHOWN ON THE AIR 2 CRAFT SPECIFICATION FOR ALL FLIGHT DATUM FORWARD LIMIT FIGURE 10 7 Operating center of gravity range scales under the landing gear tires a vertical line passing through the centerline of the axle will locate the point on the scale at which the weight is concentrated This point is called the weighing point Other structural locations capable of supporting the aircraft such as jack pads on the main spar may also be used if the aircraft weight is resting on the jack
92. ATION OF PRINTED SLEEVES Polyolefin sleeving should be used in areas where resistance to solvent and synthetic hydraulic fluids is necessary Sleeves may be secured in place with cable ties or by heat shrinking The identification sleeving for various sizes of wire is shown in table 11 17 Par 11 210 AC 43 13 1B TABLE 11 17 Recommended size of identification sleeving Wire Size Sleeving Size Nominal ID inches 3 8 inch 1 2 inch 1 2 inch 5 8 inch 5 8 inch 3 4 inch 3 4 inch IDENTIFICATION OF WIRE BUNDLES AND HARNESSES The identification of wire bundles and harnesses is becoming a common practice and may be accomplished by the use of a marked sleeve tied in place or by the use of pressure sensitive tape as indicated in figure 11 25 PRESSURE SENSITIVE TAPE SLEEVE MARKER TIED IN PLACE FIGURE 11 25 Identification of wire bundles and harnesses Page 11 566 9 8 98 Wires for which identifications are reassigned after installation may be remarked on sleeves at the termination of each wire segment It may be necessary to reidentify such wires throughout their lengths to facilitate ease of maintenance For high density harnessed shielded and jacketed multiconductor cables and when using nonsignificant wire identification color coding or its alphanumeric equivalent may be interchanged within the same harnesses The alphanumeric equivalent of the color code should be as set forth in MIL STD 681
93. C 43 13 1B or composite dust caps attached by their normal mating method Plugs may have a dust cap similar to above or have a piece of polyolefin shrink sleeving shrunk over the connector starting from the backshell threads with a tail sufficiently long enough to doubleback over the connector and be tied with polyester lacing tape behind the coupling nut The cable identification label should be visible behind the connector or a tag should be attached identifying the associated circuit or attaching equipment The connector should be attached to structure by its normal mounting means or by the use of appropriate clamps Ensure that connectors are fully mated by checking position and tightness of coupling ring or its alignment with fully mated indicator line on receptacle if applicable Ensure that the coupling nut of MS connectors is safetied by wire or other mechanical locking means as required by applicable aircraft instructional manuals Ensure that moisture absorbent material is not used as fill for MS3057 clamps or adapters Ensure that there is no evidence of deterioration such as cracking missing or disintegration of the potting material Identical connectors in adjacent locations can lead to incorrect connections When such installations are unavoidable the attached wiring must be clearly identified and must be routed and clamped so that it cannot be mismatched Connectors in unpressurized areas should be posi
94. ER COVERED RECOMM MIN MIN MIN OPER BURST PROOF BEND PRESS PRESS PRESS RADIUS MIL H 8788 6 MIL H 8788 8 MIL H 8788 10 MIL H 8788 12 MIL H 8788 16 Hose Construction Seamless synthetic rubber inner Uses High pressure hydraulic tube reinforced with one fabric braid two or more steel wire pneumatic coolant fuel and oil braids and covered with a synthetic rubber cover for gas applications request perforated cover Operating Temperatures Minus 65 F to plus 200 F Identification Hose is identified by specification number size number quarter year and year hose manufacturer s identification Par 9 30 Page 9 432 9 8 98 AC 43 13 1B RIGHT WAY WRONG WAY Do not bend or twist the hose as BE SSR illustrated Allow enough slack in the hose line to provide for changes in length when pressure is applied The hose will change in length from 296 to 4 Metal end fittings cannot be considered as part of the flexible portion of the assembly The use of elbows and adapters will ensure easier installation and in many installations will remove the strain from the hose line and greatly increase service life At all times keep the minimum bend radii of the hose as large as possible to avoid tube collapsing FIGURE 9 9 Proper hose installations Par 9 30 Page 9 433 AC 43 13 1B 9 8 98 13 25 To HUBS 48 33 40 24 THE UH SEOUL SERIE
95. HT AND BALANCE EXTREME GIVEN Actual empty weight of the aircraft 1169 Empty weight center of gravity 10 6 Maximum 1 2100 Rearward C G limit 21 9 Oil capacity 9 17 at 49 Baggage placarded do not exceed 100 165 100 at 75 5 Two passengers in rear seat 170 x 2 340 at 48 Pilot in most rearward seat equipped with controls unless otherwise placarded 1708 at 16 Since the fuel tank is located aft of the rearward limit full fuel must be used 240 at 22 Information should be obtained from the aircraft specification Note If fuel tanks are located ahead of the rearward C G limit minimum fuel should be used CHECK OF REARWARD WEIGHT AND BALANCE EXTREME PO Weight x Arm Moment 9 Total 1203601
96. Institute of Standards and Technology Standards established by the test equipment manufacturer If foreign manufactured test equipment the standards of the country where it was manufactured if approved by the Administrator The technician must make sure that the test equipment used for such maintenance is the equipment called for by the manufacturer or equivalent Before acceptance a comparison should be made between the specifications of the test equipment recommended by the manufacturer and those proposed by the repair facility The test equipment must be capable of performing all normal tests and checking all parameters of the equipment under test The level of accuracy should be equal to or better than that recommended by the manufacturer For a description of avionics test equipment used for troubleshooting refer to the equipment or aircraft manufacturing instruction manual TEST EQUIPMENT CALIBRATION Test equipment such as meters torque wrenches static and transponder test equipment should be checked at least once a year National Institute of Standards and Technology traceability can be verified by reviewing test equipment calibration records for references to National Institute of Standards and Technology test report numbers These numbers certify traceability of the equipment used in calibration If the repair station uses a standard for performing calibration that calibration standard cannot be used t
97. KHEAD WIRE PROTECTION Feed through bushing protection should be given to wire bundles which pass through bulkheads frames and other similar structure Feed through bushings of hard dielectric material are satisfactory The use of split plastic grommets nylon is recommended in lieu of rubber grommets in areas subject to fluids since they eliminate the unsatisfactory features of rubber grommets and are resistant to fluids usually encountered in aircraft SPECIAL PURPOSE CONNECTOR Many special purpose connectors have been designed for use in aircraft applications such as subminiature connector rectangular shell connector connectors with short body shells or connector of split shell construction used in applications where potting is required Make every attempt to identify the connector part number from the maintenance manual or actual part and the manufacturer s instruction used for servicing POTTING COMPOUNDS Many types of potting compounds both commercial and per military specifications are available and offer various characteristics for different applications Carefully consider the characteristics desired to ensure the use of the proper Par 11 239 AC 43 13 1B compound Preparation and storage of potting materials should receive special attention Careful inspection and handling during all stages of the connector fabrication until the potting compound has fully cured is recommended Potting compounds selected m
98. L and being permitted to produce the wire Aircraft manufacturers who maintain their own wire specifications invariably exercise close control on their approved 9 8 98 sources Such military or original equipment manufacturer OEM wire used on aircraft should only have originated from these defined wire mills Aircraft wire from other unauthorized firms and fraudulently marked with the specified identification must be regarded as unapproved wire and usually will be of inferior quality with little or no process control testing Efforts must be taken to ensure obtaining authentic fully tested aircraft wire Platings Bare copper develops a surface oxide coating at a rate dependent on temperature This oxide film is a poor conductor of electricity and inhibits retermination of wire Therefore all aircraft wiring has a coating of either tin silver or nickel that have far slower oxidation rates Tin coated copper is a very common plating material Its ability to be successfully soldered without highly active fluxes diminishes rapidly with time after manufacture It can be used up to the limiting temperature of 150 C Silver coated wire is used where temperatures do not exceed 200 392 F Nickel coated wire retains its properties beyond 260 C but most aircraft wire using such coated strands have insulation systems that cannot exceed that temperature on long term exposure Soldered terminations of nickel plate
99. N emergency generator emf electromotive force EMF I electromechanical flight instrument EMI Electromagnetic interference EP AVAIL external power available EP external power AC 43 13 1B Appendix 2 EPC external power contactor EPCS electronic power control switch EPROM erasable programmable read only memory eV electron volt EXCTR exciter EXT PWR external power FAA Federal Aviation Administration FAA PMA Federal Aviation Administration Parts Manufacturer Approval M frequency modulation M CW frequency modulation continuous wave MC flight management computer MCD flight management computer control display unit FMCS flight management computer system FMS flight management system FOD foreign object damage FREQ frequency FSEU flap slat electronic unit FW or FWD forward G S zlide slope GAL or GALY zalley GCR zenerator control relay auxiliary contact GCU generator control unit GEB senerator circuit breaker GEN zenerator GLR zgalley load relay MA W 2zas metal arc welding MT Greenwich mean time cordinated Universal time ND PWR eround power ND RET 2round return ND SV CE ground service ND or GRD ground GPCU sround power control unit GPS zglobal positioning system GPSW zear opposition switch GPU ground power unit GPW sround proximity warning GPWS sround proximity warning system GSR ground ser
100. NUT MOUNTING RECEPTACLE AND PLUG TYPES THREAD AND TEETH FOR ACCESSORY ATTACHMENT Y HERMETICALLY SEALED FINISH A SILVER TO LIGHT IRIDESCENT YELLOW COLOR CADMIUM PLATE OVER NICKEL CONDUCTIVE 65 150C INACTIVE FOR NEW DESIGN SUPERSEDES MS27479 MS27480 MS27481 MS27482 MS27483 MS27500 MS27503 MS27504 MS27664 FIGURE 11 35 Connector information example Par 11 230 Page 11 573 AC 43 13 1B lioc CONTACT STYLE INSERT ARRANGEMENT FINISH MS27484 STRAIGHT PLUG EMI GROUNDING MS27497 WALL RECEPTACLE BACK PANEL MOUNTING MS27499 BOX MOUNTING RECEPTACLE MS27500 90 PLUG NOTE 1 MS27503 HERMETIC SOLDER MOUNT RECEPTACLE NOTE 1 MS27504 BOX MOUNT RECEPTACLE NOTE 1 MS27508 BOX MOUNT RECEPTACLE BACK PANEL MOUNTING MS27513 BOX MOUNT RECEPTACLE LONG GROMMET MS27664 WALL MOUNT RECEPTACLE BACK PANEL MOUNTING NOTE 1 MS27667 THRU BULKHEAD RECEPTACLE FINISH CONTD B OLIVE DRAB CADMIUM PLATE OVER SUITABLE UNDERPLATE CONDUCTIVE 65 C TO 175 C ANODIC NONCONDUCTIVE 65 TO 175 D FUSED TIN CARBON STEEL CONDUCTIVE 65 C TO 150 C CORROSION RESISTANT STEEL CRES PASSIVATED CONDUCTIVE 65 C TO 200 C ELECTROLESS NICKEL COATING CONDUCTIVE 65 C TO 200 C HERMETIC SEAL OR ENVIRONMENT RESISTING CRES CONDUCTIVE PLATING 65 C TO 200 C CONTACT STYLE WITHOUT PIN CONTACTS WITHOUT SOCKET CONTACTS FEED THROUGH PIN CONTACTS INCLUDING HERMETICS WITH SOLDER C
101. S21266 GROMMET ANGLE BRACKET WITH TWO POINT FASTENING IGURE 11 14 Clamping at a bulkhead hole 11 148 11 154 RESERVED Par 11 155 Page 11 541 Par 11 155 9 8 98 AC 43 13 1B SECTION 12 WIRE INSULATION AND LACING STRING TIE GENERAL Insulation of wires should be appropriately chosen in accordance with the environmental characteristics of wire routing areas Routing of wires with dissimilar insulation within the same bundle is not recommended particularly when relative motion and abrasion between wires having dissimilar insulation can occur Soft insulating tubing spaghetti cannot be considered as mechanical protection against external abrasion of wire since at best it provides only a delaying action Conduit or ducting should be used when mechanical protection is needed INSULATION MATERIALS Insulating materials should be selected for the best combination of characteristics in the following categories Abrasion resistance Arc resistance noncarbon tracking Corrosion resistance Cut through strength Dielectric strength Flame resistance Heat distortion temperature Impact strength Mechanical strength Resistance to fluids Resistance to notch propagation Smoke emission Page 11 542 Special properties unique to the aircraft For a more complete selection of insulated wires refer to SAE AS 4372 Aerospace Wire Performance Requirement and SAE AS 4373 Test Methods for Aerospace
102. SHIELDED WIRE With the increase in number of highly sensitive electronic devices found on modern aircraft it has become very important to ensure proper shielding for many electric circuits Shielding is the process of applying a metallic covering to wiring and equipment to eliminate interference caused by stray electromagnetic energy Shielded wire or cable is typically connected to the aircraft s ground at both ends of the wire or at connectors in the cable Electromagnetic Interference EMI is caused when electromagnetic fields radio waves induce high frequency HF voltages in a wire or component The induced voltage can cause system inaccuracies or even failure therefore putting the aircraft and passengers at risk Shielding helps to eliminate EMI by protecting the primary conductor with an outer conductor Refer to MIL DTL 27500 Cable Power Electrical and Cable Special Purpose Electrical Shielded and Unshielded General Specifications 9 8 98 AC 43 13 1B TABLE 11 11 Open Wiring Voltage Rated wire Insulation Type Conductor type rating temperature maximum MIL W 22759 1 Fluoropolymer insulated TFE and TFE Silver coated copper coated glass MIL W 22759 2 Fluoropolymer insulated TFE and TFE Nickel coated copper coated glass MIL W 22759 3 Fluoropolymer insulated TFE glass Nickel coated copper TFE MIL W 22759 4 Fluoropolymer insulated TFE glass Silver coated copper FEP MIL W 22759 5 MIL W 22759 6 MIL W 22759 7
103. U battery charger unit BAT or BATT battery BCD binary coded decimal digit built in test BITE built in test equipment BITS bus interconnect transfer switch BNR binary numerical reference binary BP band pass BPCU us power control unit BT bus tie BTB bus tie breaker BTC tefore top center BUS clectrical bus 429 digital data bus C G Center of Gravity CAC caution advisory computer CAGE commercial and government entity code CAWS central aural warning system caution and warning system CB C B or CKT BKR circuit breaker CDI course deviation indicator CDU central display unit CFC lt arbon fiber composite CFDIU centralized fault display interface unit CFDS centralized fault display system CH or CHAN channel CHGR charger CKT circuit CLK clock CLR clear CMCS central maintenance computer system CMPTR computer CO carbon monoxide COA X coaxial COP copper CP control panel CRT cathode ray tube circuit CSE or CSEU control system electronics unit CSEUP control system electronics unit panel CT computed tomography CT current transformer CTN caution CU control unit copper CVR cockpit voice recorder CW continuous wave D A 4igital to analog DAC 4digital to analog converter DADC digital air data computer DBT dead bus tie dc direct current 9 8 98 DCDR decoder DDB digital
104. UPS SOCKET CONTACTS INCLUDING HERMETICS WITH SOLDER CUPS PIN CONTACTS WITH EYELET HERMETIC SOCKET CONTACTS WITH EYELET HERMETIC POLARIZATION A B NORMAL NO LETTER REQUIRED C OR D 9 8 98 AC 43 13 1B FACING VIEW PLUG RECEPTACLE 22 Av RECEPTACLE RECEPTACLE QUICK DISCONNECT STRAIGHT PLUG PLUG 55 SINGLE d UADRUPLE INSERT 2 TRIPLE 9 INSERT PLUG INSERT 4 VSERT RECEPTACLE ANGLE PLUG A PLUG ANGLE PL GER SSHS RECEPTACLE RECEPTACLE H N A gt 22 2 TYPICAL RACK AND PANEL CONNECTORS MS CONNECTOR FIGURE 11 36 Different types of connectors Par 11 232 Page 11 574 9 8 98 AC 43 13 1B STRAIGHT FLANGE MOUNT RECEPTACLE RECEPTACLE BNC Series Connectors tu STRAIGHT FLANGE MOUNT RECEPTACLE RECEPTACLE TNC Series Connectors EC STRAIGHT FLANGE MOUNT RECEPTACLE RECEPTACLE N Series Connectors STRAIGHT FLANGE MOUNT RECEPTACLE RECEPTACLE C Series Connectors Par 11 232 Page 11 575 9 8 98 AC 43 13 1B 0 0 ae BULKHEAD FLANGE MOUNT RECEPTACLE RECEPTACLE 0 O 0 STRAIGHT PLUG STRAIGHT RECEPTACLE FLANGE MOUNT RECEPTACLE SC Series Connectors SMA Series Connectors Sty 8 Sea Rey STRAIGHT PLUG ANGLE PLUG STRAIGHT RECEPTACLE JAM NUT RECEPTACLE SMB Series Connectors 2 STRAIGHT PLUG STRAIGHT RECEPTACLE JAM NUT RECEPTACLE ANGLE PLUG SMC Series Connectors FIGURE
105. Wire For termination of shielded wire refer to MIL DTL 27500 ATTACHMENT OF TERMINALS TO STUDS Connectors and terminals in aircraft require special attention to ensure a safe and satisfactory installation Every possibility of short circuits due to misinstallation poor maintenance and service life should be addressed in the design Electrical equipment malfunction has frequently been traced to poor terminal connections at terminal boards Loose dirty or corroded contact surfaces can produce localized heating that may ignite nearby combustible materials or overheat adjacent wire insulation STUDS AND INSULATORS The following recommendations concerning studs also apply to other feed through conductors Current Carrying Stud Resistance Due to heat loss arising from wire to lug and lug to stud voltage drop the resistance per unit length of a current carrying stud should not be greater than that of the wire Size of Studs In designing the stud for a feed through connection attention should be given to the higher resistance of brass as compared to copper A suggested method of determining the size is to use a current density in the stud equivalent to that of the wire compensating for the difference of resistance of the metals Consideration should also be given to mechanical strength Support for Studs The main stud support in the feed through insulation should be independent of the attachment of the lugs to Page 11 54
106. a slow rate After the refilling operation is completed check for leaks with a leak detector If a leak is detected paragraph 9 49b 2 d should be referred to for corrective action 9 8 98 AC 43 13 1B TABLE 9 5 Table of filling pressures Initial Temp Filling Pressure F psi 160 po EO 1 700 Initial Temperature Refers to the ambient temperature in the filling room Filling Pressure Refers to the pressure to which aircraft cylinders should be filled This table gives approximations only and assumes a rise in temperature of approximately 25 F due to the heat of compression This table also assumes the aircraft cylinders will be filled as quickly as possible and that they will only be cooled by ambient air with no water bath or other means of cooling being used Example f ambient temperature is 70 F fill aircraft cylinders to approximately 1 975 psi as close to this pressure as the gauge may be read Upon cooling cylinders should have approximately 1 850 psi pressure 9 52 9 59 RESERVED Par 9 51 Page 9 455 and 9 44 Par 9 60 9 8 98 AC 43 13 1B SECTION 4 CABIN INTERIOR GENERAL Only materials that are flash resistant should be used in cabin interiors The requirements related to fire protection qualities of cabin interior materials are specified in CAR 3 388 fire precautions or 14 CFR part 23 section 23 853 compartment interiors CAR 3 AIRCRAFT INTERIOR The requirement f
107. ability of the electrical system Damaged wiring or equipment in an aircraft regardless of how minor it may appear to be cannot be tolerated Reliability of the system is proportional to the amount of maintenance received and the knowledge of those who perform such maintenance It is therefore important that maintenance be accomplished using the best techniques and practices to minimize the possibility of failure This chapter is not intended to supersede or replace any government specification or specific manufacturer s instruction regarding electrical system inspection and repair INSPECTION AND OPERATION CHECKS Frequently equipment electrical assemblies and wiring installations for damage general condition and proper functioning to ensure the continued satisfactory operation of the electrical system Adjust repair overhaul and test electrical equipment and systems in accordance with the recommendations and procedures in the aircraft and or component manufacturer s maintenance instructions Replace componenis of the electrical system that are damaged or defective with identical parts with aircraft manufacturer s approved equipment or its equivalent to the original in operating characteristics mechanical strength and environmental specifications A list of suggested problems to look for and checks Refer to the glossary for a description of the check types to be performed are Par 11 1 Page 11 483
108. age 9 443 AC 43 13 1B A rip or tear across an air retaining seam Rafts on which oil grease or any other foreign substance has caused a deterioration of the rubberized fabric Rafts on which a heavy mildew condition has caused deterioration of the rubberized fabric Rafts on which porous flotation tubes allow diffusion of air A porous area is located by a soap test on the inflated raft Higher diffusion is indicated by the excessive loss of pressure after a soap test has failed to locate a specific area of injury on the raft Rafts requiring internal repair or opening of air retaining seams for repair Rafts with an excessive number of injuries that would not in the judgment of competent inspectors justify repair Patches Holes or abrasions which are 2 inches or less in diameter in air retaining chambers will be repaired by the application of an outside patch Holes exceeding 2 inches in length or diameter will require an inside patch as well as an outside patch Inside and outside patches should be round rectangular and manufactured of fabric specification MIL C 6819 Cement should conform to Class 1 of specification MIL C 5539 Patch as follows Outside patches With a rubber solvent thoroughly clean the area to be patched From the material referenced fabricate a patch as shown in figure 9 13 9 8 98 Par 9 42 When two fabric surfaces are to be bonded apply two coats of extra light cement tw
109. age 9 444 AC 43 13 1B center line and cross lines on the ends of the patch will coincide with the ends of the injury To ensure that the inside surface of the raft is properly powdered in the area of repair pass a small handful of talc through the opening in the raft and place it approximately 12 inches from the injury This should be accomplished before the inside area is cemented exercising care to prevent distribution of the talc prior to completion of the repair DOTTED LINES INDICATE INJURY FIGURE 9 13 Repair dimensions Using cleaning solvent cleanse an area on the inside surface of the fabric slightly larger than the patch to be applied Ensure that the repaired area is thoroughly dry both inside and outside apply two coats of extra light cement two coats of light cement and three coats of heavy cement or six additional coats of light cement in lieu of the heavy cement to the cleansed area allowing each coat to dry thoroughly before applying successive coats NOTE Since it is impossible for the repairman to visually observe the cementing that is being accomplished on the inside of the raft exercise care to ensure that each coat of cement completely covers the area to be repaired 9 8 98 The inside patch should be cemented simultaneously with the application of cement to the inside of the raft Apply the same number of coats as directed in paragraph 9 42b 2 d to the side of the patch that is applie
110. ainters for woods with large pores such as oak ash chestnut and walnut Also known as coarse textured operational check this is an operational test to determine whether a system or component is functioning properly in all aspects in conformance with minimum acceptable manufacture design specifications optical fiber any filament or fiber made of dielectric materials that guides light whether or not it is used to transmit signals orifice opening through which gas or air flows It is usually the final opening controlled by a valve oxidizing combining oxygen with any other substance For example a metal is oxidized when the metal is burned i e oxygen is combined with all the metal or parts of it 622 9 8 98 oxidizing flame an oxy fuel gas flame having an oxidizing effect due to excess oxygen oxygen cutting cutting metal using the oxygen jet which is added to an oxygen acetylene flame oxygen regulator manually adjustable device used to reduce cylinder pressure to torch pressure and to keep the pressure constant They are never to be used as fuel gas regulators peel ply a layer of resin free material used to protect a laminate for later secondary bonding sometimes referred to as a release film pickling the treatment of a metal surface by an acid to remove surface corrosion pitch is the distance in inches that a propeller section will move forward in one revolution or the dista
111. al dissimilar metals for protection from exposure to the atmosphere Par 11 189 Page 11 555 AC 43 13 1 Corrosion Prevention Electrolytic action may rapidly corrode a bonding connection if suitable precautions are not taken Aluminum alloy jumpers are recommended for most cases however copper jumpers should be used to bond together parts made of stainless steel cadmium plated steel copper brass or bronze Where contact between dissimilar metals cannot be avoided the choice of jumper and hardware should be such that corrosion is minimized and the part likely to corrode would be the jumper or associated hardware Tables 11 14 through 11 16 and figures 11 20 through 11 22 show the proper hardware combinations for making a bond connection At locations where finishes are removed a protective finish should be applied to the completed connection to prevent subsequent corrosion Bonding Jumper Attachment The use of solder to attach bonding jumpers should be avoided Tubular members should be bonded by means of clamps to which the jumper is attached Proper choice of clamp material should minimize the probability of corrosion Ground Return Connection When bonding jumpers carry substantial ground return current the current rating of the jumper should be determined to be adequate and that a negligible voltage drop is produced CREEPAGE DISTANCE Care should be used in the selection of electrical components to ensure that el
112. al to metal contact is maintained LIGHTNING PROTECTION BONDING Electrical bonding is frequently required for lightning protection of aircraft and systems especially to facilitate safe conduction of lightning currents through the airframe Most of this bonding is achieved through normal airframe riveted or bolted joints but some externally mounted parts such as control surfaces engine nacelles and antennas may require additional bonding provisions Generally the adequacy of lightning current bonds depends on Par 11 190 Page 11 560 AC 43 13 1B materials cross sections physical configurations tightness and surface finishes Care should be taken to minimize structural resistance so as to control structural voltage rises to levels compatible with system protection design This may require that metal surfaces be added to composite structures or that tinned copper overbraid conduits or cable trays be provided for interconnecting wire harnesses within composite airframes Also care must be taken to prevent hazardous lightning currents from entering the airframe via flight control cables push rods or other conducting objects that extend to airframe extremities This may require that these conductors be electrically bonded to the airframe or that electrical insulators be used to interrupt lightning currents For additional information on lightning protection measures refer to DOT FAA CT 89 22 Report DOT FAA CT 86 8 April
113. and thermal properties for the application Sufficient cross section should be provided to ensure adequate conductivity against overheating Secure through bolts mechanically and independently of the terminal mounting nuts taking particular care to avoid dissimilar metals among the terminal hardware During inspection pay particular attention to the condition of the insulator plate or spacer and the insulating boot that covers the completed terminal assembly IDENTIFY SPARE WIRES WITH CODE LETTER TO SPOND WITH CONTACT FILL ALL SPARE CONTACTS WITH MAXIMUM SIZE WIRES Par 11 239 Page 11 580 and 11 100 9 8 98 AC 43 13 1B FIGURE 11 38 Spare wires for potting connector 11 241 11 247 RESERVED Par 11 239 Page 11 581 and 11 100 9 8 98 AC 43 13 1B SECTION 18 CONDUITS GENERAL Conduit is manufactured in metallic and nonmetallic materials and in both rigid and flexible forms Primarily its purpose is for mechanical protection of cables or wires Conduit should be inspected for proper end fittings absence of abrasion at the end fittings proper clamping distortion adequate drain points which are free of dirt grease or other obstructions and freedom from abrasion or damage due to moving objects such as aircraft control cables or shifting cargo SIZE OF CONDUIT Conduit size should be selected for a specific wire bundle application to allow for ease in maintenance and possible future circuit ex
114. and vice versa BATTERY CHARGING Operation of storage batteries beyond their ambient temperature or charging voltage limits can result in excessive cell temperatures leading to electrolyte boiling rapid deterioration of the cells and battery failure The relationship between maximum charging voltage and the number of cells in the battery is also significant This will determine for a given ambient temperature and state of charge the rate at which energy is absorbed as heat within the battery For lead acid batteries the voltage per cell must not exceed 2 35 volts In the case of NiCad batteries the charging voltage limit varies with design and construction Values of Page 11 486 1 4 and 1 5 volts per cell are generally used In all cases follow the recommendations of the battery manufacturer BATTERY FREEZING Discharged lead acid batteries exposed to cold temperatures are subject to plate damage due to freezing of the electrolyte To prevent freezing damage maintain each cell s specific gravity at 1 275 or for sealed lead acid batteries check open circuit voltage See table 11 1 NiCad battery electrolyte is not as susceptible to freezing because no appreciable chemical change takes place between the charged and discharged states However the electrolyte will freeze at approximately minus 75 F NOTE Only a load check will determine overall battery condition TABLE 11 1 Lead acid battery electrolyte free
115. arcing loads Proximity sensors generally use a relatively low energy electromagnetic field to sense the target Adequate spacing is required to prevent interference between adjacent proximity sensors or other devices susceptible to EMI RFI Refer to manufacturer s instructions Temperature Electromechanical switches can withstand wide temperature ranges and rapid gradient shifts without damage Most aircraft switches operate between 55 C 85 C with designs available from 185 C to 260 or more Higher temperatures require more exotic materials which can increase costs and limit life It should be noted that o ring seals and elastomer boot seals tend to stiffen in extreme cold This can increase operating forces and reduce release forces or stop the switch from releasing Proximity sensors are normally designed for environments from 55 C to 125 C During temperature excursions the operating and release points may shift from 5 percent to 10 percent Reliability of the proximity sensor will typically be highest at room temperature The reliability and MTBF estimates should be reduced for use under high temperatures or high thermal gradients Sealing NOTE The materials used for sealing o rings potting materials etc should be compatible with any aircraft fluids to which the switch may be exposed Page 11 499 9 8 98 Electromechanical switches range in sealing from partially sealed to hermetically sea
116. at particular use Insulation tape should be used primarily as a filler under clamps and as secondary support Nonadhesive tape may be used to wrap around wiring for additional protection such as in wheel wells All tape should have the ends tied or otherwise suitably secured to prevent unwinding Tape used for protection should be applied so that overlapping layers shed liquids Drainage holes should be provided at all trap points and at each low point between clamps Plastic tapes that absorb moisture or have volatile plasticizers that produce chemical reactions with other wiring should not be used Reference MIL W 5088 9 8 98 AC 43 13 1B PULL HERE UNTIL TIGHT BEFORE FINISHING KNOT CORD CROSSES UNDER LOOP 7 FIRST PART OF FINAL STEP c PART I KNOT TIGHTENED STEP c PART Il FINAL KNOT STEP a STARTING KNOT BOWLINE ON A BIGHT STARTING KNOT TIGHTENED FIGURE 11 16 Double cord lacing Par 11 167 Page 11 544 and 11 66 9 8 98 AC 43 13 1B WRAP CORD TWICE 3s CLOVE HITCH amp OVER BUNDLE SQUARE KNOT FIGURE 11 17 Making ties 11 160 11 166 RESERVED Par 11 167 Page 11 545 and 11 66 Par 11 167 9 8 98 SECTION 13 GENERAL Splicing is permitted on wiring as long as it does not affect the reliability and the electromechanical characteristics of the wiring Splicing of power wires coaxial cables multiplex bus and large gauge wire must have approved data Splicing of
117. ate an indent greater than 10 percent of the insulation wall CAUTION The traditional Hot Stamp method has not been totally satisfactory when used on ultra thin walled insulation Fracture of the insulation wall and penetration to the conductor of these materials by the stamping dies have occurred Later in service when these openings have been wetted by various fluids serious arcing and surface tracking will have damaged wire bundles DOT MATRIX MARKING The dot matrix marking is imprinted onto the wire or cable very similar to that of a dot matrix computer printer The wire must go through a cleaning process to make sure it is clean and dry for the ink to adhere Wires marked with dot matrix equipment require a cure consisting of an UV curing process which is normally applied by the marking equipment This cure should normally be complete 16 to 24 hours after marking Dot matrix makes a legible mark without damaging the insulation Depending on equipment configuration dot matrix can mark wire from 0 037 to 0 5 inch outside diameter Multiconductor cable can also be marked INK JET MARKING This is a nonimpact marking method wherein ink droplets are electrically charged and then directed onto the moving wire to form the characters Two basic ink types are available thermal cure and UV cure Thermal cure inks must generally be heated in an oven for a length of time after Par 11 210 AC 43 13 1B marking to ob
118. ater loss due to overcharging in normal service Batteries that become fully discharged may not accept recharge Lead acid sealed batteries are similar in most respects to lead acid vented batteries but do not require the addition of water The lead acid battery is economical and has extensive application but is heavier than an equivalent performance battery of another type The battery is capable of a high rate of discharge and low temperature performance However maintaining a high rate of discharge for a period of time usually warps the cell plates shorting out the battery Its electrolyte has a moderate specific gravity and state of charge can be checked with a hydrometer Do not use high amperage automotive battery chargers to charge aircraft batteries NiCad vented batteries have 1 2 volt nominal cell voltage Occasional addition of distilled water is required to replace water loss due to overcharging in normal service Cause of failure is usually shorting Par 11 19 Page 11 488 AC 43 13 1B weakening of a cell After replacing the bad cell with a good cell the battery s life can be extended for five or more years Full discharge is not harmful to this type of battery NiCad sealed batteries are similar in most respects to NiCad vented batteries but do not normally require the addition of water Fully discharging the battery to zero volts may cause irreversible damage to one or more cells leadi
119. ation on terminals 9 8 98 CIRCUIT BREAKERS Note those circuit breakers which have a tendency to open circuits frequently require resetting more than normal or are subject to nuisance tripping Before considering their replacement investigate the reason SYSTEM SEPARATION Wires of redundant aircraft systems should be routed in separate bundles and through separate connectors to prevent a single fault from disabling multiple systems Wires not protected by a circuit protective device such as a circuit breaker or fuse should be routed separately from all other wiring Power feeders from separate sources should be routed in separate bundles from each other and from other aircraft wiring in order to prevent a single fault from disabling more than one power source The ground wires from aircraft power sources should be attached to the airframe at separate points so that a single failure will not disable multiple sources Wiring that is part of electro explosive subsystems such as cartridge actuated fire extinguishers rescue hoist shear and emergency jettison devices should be routed in shielded and jacketed twisted pair cables shielded without discontinuities and kept separate from other wiring at connectors To facilitate identification of specific separated system bundles use of colored plastic cable ties or lacing tape is allowed During aircraft maintenance colored plastic cable straps or lacing tape should be replac
120. avoid surging which could rupture the line Regulators Valves and Gauges Examine all parts for cracks nicks damaged threads or other apparent damage Actuate the regulator controls and the valve to check for ease of operation Determine if the gauge is functioning properly by observing the pressure build up and the Par 9 46 Page 9 449 AC 43 13 1B return to zero when the system oxygen is bled off 9 8 98 AC 43 13 1B Masks and Hoses Check the oxygen mask for fabric cracks and rough face seals If the mask is a full face model inspect the glass or plastic for cleanliness and state of repair When appropriate with due regard to hygienic considerations the sealing qualities of an oxygen mask may be tested by placing a thumb over the connection at the end of the mask tube and inhaling very lightly Remove the thumb from the disconnect after each continuous inhalation If there is no leakage the mask will adhere tightly to the face during inhalation and definite resistance to inhalation will be noticeable Flex the mask hose gently over its entirety and check for evidence of deterioration or dirt Examine the mask and hose storage compartment for cleanliness and general condition If the mask and hose storage compartment is provided with a cover or release mechanism thoroughly check the operation of the mechanism MAINTENANCE Oxygen Tanks Cylinders and Hold Down Brackets Remove from service a
121. ay destroying the battery and creating a possible safety hazard to the aircraft DEFINITION Thermal runaway can result in a chemical fire and or explosion of the NiCad battery under recharge by a constant voltage source and is due to cyclical ever increasing temperature and charging current One or more shorted cells or an existing high temperature and low charge can produce the cyclical sequence of events 1 excessive current 2 increased temperature 3 decreased cell s resistance 4 further increased current and 5 further increased temperature This will not become a self sustaining thermal chemical action if constant voltage charging source is removed before the battery temperature is in excess of 160 F Pulsed current battery chargers are sometimes provided for NiCad batteries CAUTION It is important to use the proper charging procedures for batteries under test and maintenance These charging regimes for reconditioning and charging cycles are defined by the aircraft manufacturer and should be closely followed Shop Level Maintenance Procedures Shop procedures must follow the manufacturer s recommendations Careful examination of sealed batteries and proper reconditioning of vented batteries will ensure the longest possible service life Par 11 19 AC 43 13 1B Aircraft Battery Inspection Inspect battery sump lines for condition and security jar and Inspect battery terminals and
122. b wires to taper wire bundle Secure wire ends with high temperature greater than 250 C lacing cord Nylon cable ties are not allowed for this installation Par 11 260 Page 11 584 NOTE Both connectors mating through the engine fire seal are considered firewall connectors Connectors mounted on or near but not through the engine fire seal are not considered firewall connectors Non firewall Connector Installations In this type of installation all unused connector cavities must also be filled with spare contacts It is not required however to crimp stub wires on filling contacts Fill unused contact cavities with spare contacts and Teflon sealing plugs or rods See figure 11 40 Rods shall be cut so that they extend 1 8 to 1 4 inch beyond the surface of the grommet when bottomed against the end of the spare contact See table 11 26 for dimensions PRESSURIZED AREAS Connectors installed in pressurized areas of the aircraft may be divided into two main installation categories sealed and unsealed Sealed connector installations Sealed connectors installed in pressurized areas must have their unused contact cavities filled with Teflon sealing plugs or rods See figure 11 40 Installation of spare contacts is optional except for future wiring addition requirements See paragraph 11 234 No stub wires are required Unsealed Connector Installations It is not required to fill unused contact cavities of unsealed connec
123. be held at the desired angle until cool SERVICE LOOP Primary support for service loop harness es should be a cushion clamp and a connector at the harness termination Service loop harnesses should be inspected for the following Adequate Length Components should extend out from their mounting position a distance that permits rotating and unlocking or locking the electrical connector Usually a distance of 3 to 6 inches with all other components installed should be sufficient Bundle BreakOut Point Bundle breakout point should be adequately supported with string tie Service loop must maintain a minimum bend radius of 3 times the harness diameter The breakout point should be located directly behind beside below or above the component so that the service loop harness does not bind other components Plastic ties should not be used between the service loop breakout and the electrical connector when they are likely to chafe against adjacent wire 9 8 98 AC 43 13 1B Service Loop Routing The service loop harness should be routed directly from the breakout point to the component The harness should not contact moving mechanical components or linkage and should not be wrapped or tangled with other service loop harnesses Service Loop Harness Termination Strain relief should be provided at the service loop harness termination and is normally provided by the connector manufacturer s backshell heat shrinkable bo
124. be moved to access electrical connectors are connected to aircraft wiring through service loops Chafing in service loop harnesses is controlled using the following techniques SUPPORT Only string ties or plastic cable straps in accordance with paragraph 11 158 should be used on service loop harnesses A 90 or Y type spot tie should be installed at the harness breakout point on the harness bundle Ties should be installed on service loop harnesses at 4 to 6 inch intervals ANTI CHAFING MATERIAL When service loops are likely to be in contact with each other expandable sleeving or equivalent chafe protection jacket material must be installed over service loop harnesses to prevent harness to harness chafing The sleeve should be held in place with string ties at 6 to 8 inch intervals Harness identification labels should be installed with string tie within 3 inches of the service loop harness installation STRAIN RELIEF The strain relief components may be installed to control routing where close clearance exists between termination and other components or bulkheads Sirain relief components provide support of the service loop harness at the termination point Connector sirain relief adapters Page 11 536 heat shrinkable boot or a length of heat shrinkable tubing should be installed The heat shrinkable boots will provide preselected angles of wire harness termination when heat is applied Heat shrinkable tubing should
125. c instructions the wheel retaining nut 15 tightened until bearing drag is felt The nut is then backed off about one serration castellation or one sixth turn before bending up the tab on the tab lock washer or installing the cotter pin The grease cover or wheel cover if used is then installed During this installation any required brake air pressure sensors and speed sensor components should be installed and connected as appropriate for the specific aircraft REASSEMBLING THE WHEEL The correct assembly of the wheel affects the balance of the tire After the wheel halves and bolts nuts have been inspected and found serviceable put a little talc on the tube and insert it in the tire Align the heavy spot of the tube usually marked with a yellow line with the light spot of the tire usually marked with a red dot If the tube does not have a balance mark align the valve of the tube with the balance mark on the line Remove the valve core and inflate the tube momentarily to seat the tube and let the air run out Put one wheel half in the tire and align the wheel half with the valve hole up with the valve on the tube Insert the other wheel half in the tire and align the bolt holes Insert the wheel bolts and torque to the manufacturer s recommended value 9 8 98 AC 43 13 1B NOTE It is highly recommended that the tire be placed in a cage so that if the wheel fails the mechanic is protected from injury Again inflate
126. ce personnel to facilitate shipping because this procedure can conceal damage Propeller tip damage will sometimes lead maintenance personnel to consider removing damaged material from the blade tips However propellers are often manufactured with a particular diameter to minimize vibration Unless the TCDS and both the engine and propeller manufacturers specifically permit shortening of the blades on a particular propeller any shortening of the blades would probably create an unairworthy condition When conditions warrant inspect the blade tips for evidence of shortening and if necessary measure the propeller diameter to determine if it has been changed by an unauthorized repair PROPELLER HUB Fixed Pitch Inspection procedures require removal of the propeller spinner for examination of the prop hub area Cracks may be present in the hub area between or adjacent to bolt holes and along the hub pilot bore Cracks in these areas cannot be repaired require immediate scrapping of the propeller Propeller attach bolts should be examined for looseness or an unsafetied or cracked condition Cracked or broken bolts are usually the result of overtorquing Correct 9 8 98 AC 43 13 1B torquing procedures require all bolt threads to be dry clean and free of any lubrication before torquing Controllable Pitch Inspect controllable pitch propellers frequently to determine that all parts are lubricated properly It is espe
127. cially recommended that all lubrication be accomplished in accordance with the propeller manufacturer s instructions Complete inspection servicing requires the removal of the spinner for examination and servicing of the propeller hub and blade clamp area All inspections and servicing of the pitch control mechanism should follow the recommendations of the propeller engine and airframe manufacturers Propellers must be in compliance with applicable AD s and manufacturer s SB s The hub blade clamps and pitch change mechanisms should be inspected for corrosion from all sources including rain snow and bird droppings that may have entered through the spinner openings Examine the hub area for oil and grease leaks missing grease fitting caps and leaking or missing grease fittings Propeller domes should be checked for leaks both at the seals and on the fill valve if so equipped The dome valve may be leak tested by applying soapy water over the fill valve end Domes should be serviced only with nitrogen or dry air in accordance with the manufacturer s recommendations When propeller domes are inspected and found filled with oil the propeller should be removed and inspected repaired by an appropriately rated repair facility It is especially recommended that all lubrication be accomplished at the periods and Par 8 107 Page 8 405 9 8 98 AC 43 13 1B in the manner specified by the propeller manufacturer On makes and models with a grease
128. cification or type certificate data sheet Straighten Propeller Blades damaged propeller Never straighten a Even partial AC 43 13 1B straightening of blades to permit shipment to a certificated propeller repair facility may result in hidden damage not being detected and an unairworthy propeller being returned to service REPAIR LIMITS The following limits are those listed in the blade manufacturing specification for aluminum alloy blades and govern the width and thickness of new blades These limits are to be used with the pertinent blade drawing to determine the minimum original blade dimensions to which the reduction of figure 8 27 and figure 8 28 may be applied When repairs reduce the width or thickness of the blade below these limits reject the blade The face alignment or track of the propeller should fall within the limits recommended by the manufacturer for new propellers REFERENCE EDGE OF TEMPLATE OUTLINE OF NEW TIP SHEET ALUMINUM TIP TEMPLATE ALL BLADES ON THE SAME PROPELLER MUST BE SHORTENED EXACTLY THE SAME PENCIL LINE DRAWN ON BLADE AT SELECTED STATION FOR TEMPLATE REFERENCE PLAN VIEW OF BLADE WITH DAMAGED TIP LEADING EDGE DOTTED LINE SHOWS SIDE VIEW OF NEW TIP AFTER CUTTING DOWN FIGURE 8 26 Method of repairing damaged tip of aluminum alloy propellers No repairs are permitted to the shanks roots or hub ends of aluminum alloy adjustable pitch blades The shanks must be
129. connections to prevent unintentional grounding Connectors that are susceptible to corrosion difficulties may be treated with a chemically inert waterproof jelly TYPES OF CONNECTORS Connectors must be identified by an original identification number derived from MIL Specification MS or OAM specification Figure 11 35 provides some examples of MS connector types Par 11 230 Page 11 572 Several different types are shown in figures 11 36 and 11 37 Environmental Classes Environment resistant connectors are used in applications where they will probably be subjected to fluids vibration thermal mechanical shock corrosive elements etc Firewall class connectors incorporating these same features should in addition be able to prevent the penetration of the fire through the aircraft firewall connector opening and continue to function without failure for a specified period of time when exposed to fire Hermetic connectors provide a pressure seal for maintaining pressurized areas When EMI RFI protection is required special attention should be given to the termination of individual and overall shields Backshell adapters designed for shield termination connectors with conductive finishes and EMI grounding fingers are available for this purpose Rectangular Connectors The rectangular connectors are typically used in applications where a very large number of circuits are accommodated in a single mated pair They are available with a g
130. craft Empty weight center of gravity Maximum weight Forward C G limit Oil capacity 9 qts Pilot in farthest forward seat equipped with controls unless otherwise placarded Since the fuel tank is located to the rear of the forward C G limit minimum fuel should be included METO HP 165 13 75 gal x 6 83 at 22 12 12 Information should be obtained from the aircraft specification Note Any items or passengers must be used if they are located ahead of the forward C G limit Full fuel must be used if the tank is located ahead of the forward C G limit CHECK OF FORWARD WEIGHT AND BALANCE EXTREME po Weight 4 x Arm Moment Toa 11439 16104 TM Divide the TM total moment by the TW total weight to obtain the forward weight and balance extreme TM 16104 11 2 TW 1439 Since the forward C G limit and the maximum weight are not exceeded the forward weight and balance extreme condition is satisfactory FIGURE 10 10 Example of check of most forward weight and balance extreme Par 10 16 Page 10 470 9 8 98 The minimum weights arms and moments of the items of useful load that are located ahead of the rearward c g limit A typical example of the computation necessary to make this check using this data is shown figure 10 11 LOADING CONDITIONS AND OR PLACARDS If the following items have not been covered in the weight and balance extreme
131. ctory ground for control cables LIGHTNING PROTECTION FOR ANTENNAS AND AIR DATA PROBES Antenna and air data probes that are mounted on exterior surfaces within lightning strike zones should be provided with a means to safely transfer lightning currents to the airframe and to prevent hazardous surges from being conducted into the airframe via antenna cables or wire harnesses Usually the antenna mounting bolts provide adequate lightning current paths Surge protectors built into antennas or installed in coaxial antenna cables or probe wire harnesses will fulfill these requirements Candidate designs should be verified by simulated lightning tests in accordance with RTCA DO 160C Section 23 STATIC DISCHARGE DEVICE Means should be provided to bleed accumulated static charges from aircraft prior to Par 11 193 AC 43 13 1B ground personnel coming in contact with an aircraft after landing Normally there is adequate conductivity in the tires for this but if not a static ground should be applied before personnel come into contact with the aircraft Fuel nozzle grounding receptacles should be installed in accordance with the manufacturer s specifications Grounding receptacles should provide a means to eliminate the static induced voltage that might otherwise cause a spark between a fuel nozzle and fuel tank access covers and inlets In addition static discharging wicks are installed on wings and tail surfaces to discharge stat
132. d by an authorized avionics repair facility EMERGENCY LOCATOR TRANSMITTERS ELT The ELT must be evaluated in accordance with TSO C91a TSO C126 for 406 MHz ELT s or later TSO s issued for ELT s ELT installations must be examined for potential operational problems at least once a year section 91 207 d There have been numerous instances of interaction between ELT and other VHF installations Antenna location should be as far as possible from other antennas to prevent efficiency losses Check ELT antenna installations in close proximity to other VHF antennas for suspected interference Antenna patterns of previously installed VHF antennas could be measured after an ELT installation Testing of an ELT must be performed within the first 5 minutes of an hour and only three pulses of the transmitter should be activated For example a test could be conducted between 1 00 p m and 1 05 p m with a maximum of three beeps being heard on a frequency of 121 5 MHz INSPECTION OF ELT An inspection of the following must be accomplished by a properly certified person or repair station within 12 calendar months after the last inspection Par 12 16 AC 43 13 1B Proper Installation Remove all interconnections to the ELT unit and ELT antenna Visually inspect and confirm proper seating of all connector pins Special attention should be given to coaxial center conductor pins which are prone to retracting into the connector housing R
133. d conductor require the use of different solder sleeves or flux than those used with tin or silver plated conductor Conductor Stranding Because of flight vibration and flexing conductor round wire should be stranded to minimize fatigue breakage Wire Construction Versus Application The most important consideration in the Par 11 78 AC 43 13 1B selection of aircraft wire is properly matching the wire s construction to the application environment Wire construction that is suitable for the most severe environmental condition to be encountered should be selected Wires are typically categorized as being suitable for either open wiring or protected wiring applications MIL W 5088L Appendix A table A I lists wires considered to have sufficient abrasion and cut through resistance to be suitable for open harness construction MIL W 5088L Appendix A table A II lists wires for protected applications These wires are not recommended for aircraft interconnection wiring unless the subject harness is covered throughout its length by a protective jacket The wire temperature rating is typically a measure of the insulation s ability to withstand the combination of ambient temperature and current related conductor temperature rise Insulations There are many insulation materials and combinations used on aircraft electrical wire An explanation of many of the abbreviations are identified in the glossary SUBSTITUTIONS In the
134. d have sufficient contact capacity to break make and continuously carry the connected load current The position of the switch should be checked with an electrical meter Electrical Switch Inspection Special attention should be given to electrical circuit switches especially the spring loaded type during the course of normal airworthiness inspection An internal failure of the spring loaded type may allow the switch to remain closed even though the toggle or button returns to the off position During inspection attention should also be given to the possibility that improper switch substitution may have been made With the power off suspect aircraft electrical switches should be checked in the on position for opens high resistance and in the off position for shorts low resistance with an ohmmeter Any abnormal side to side movement of the switch should be an alert to imminent failure even if the switch tested was shown to be acceptable with an ohmmeter Par 11 47 Page 11 497 AC 43 13 1B Electromechanical Switches Switches have electrical contacts and various types of switch actuators i e toggle plunger push button knob rocker Contacts designed for high level loads must not be subsequently used for low level applications unless testing has been performed to establish this capability Switches are specifically selected based on the design for the aircraft service current ratings for lamp loads induc
135. d on the flotation tube at the left of the cylinder The size of lettering will not be less than 1 4 inch or greater than 1 2 inch in height Previous inspection dates will not be removed or obliterated but will be arranged in columnar form with the latest date at the top After the inspection is completed fill out the raft s inspection record in accordance with part 43 section 43 9 and attach the parts tag to the survival equipment The date on the tag will reflect the same date as stenciled on the flotation tube and will be used to determine the next due date of inspection and test RAFT REPAIRS Repairs The service life for flotation equipment will be determined by condition rather than age Equipment passing tests and inspections may remain in service indefinitely since the inflation tests and material inspections will identify and condemn equipment having more than minor installation defects However the service life for life rafts operating under normal usage and environmental conditions is anticipated by the manufacturers to be 8to 10 years and it is appropriate to base life raft s parts replacement programs upon this estimate It is not considered advisable or economical to perform major repairs on life rafts Life Rafts Life rafts with any of the following conditions should be condemned rather than repaired Life rafts over 3 1 2 years of age and requiring major repair or more than two minor repairs Par 9 39 P
136. d security of all attachments and terminals Grease corrosion or dirt on any electrical junction may cause the connections to overheat and eventually fail Bus bars that exhibit corrosion even in limited amounts should be disassembled cleaned and brightened and reinstalled 11 9 11 14 RESERVED Par 11 8 Page 11 485 and 11 4 Par 11 15 9 8 98 AC 43 13 1B SECTION 2 STORAGE BATTERIES GENERAL Aircraft batteries may be used for many functions e g ground power emergency power improving DC bus stability and fault clearing Most small private aircraft use lead acid batteries Most commercial and military aircraft use NiCad batteries However other types are becoming available such as gel cell and sealed lead acid batteries The battery best suited for a particular application will depend on the relative importance of several characteristics such as weight cost volume service or shelf life discharge rate maintenance and charging rate Any change of battery type may be considered a major alteration Storage batteries are usually identified by the material used for the plates All battery types possess different characteristics and therefore must be maintained in accordance with the manufacturer s recommendations WARNING It is extremely dangerous to store or service lead acid and NiCad batteries in the same area Introduction of acid electrolytes into alkaline electrolyte will destroy the NiCad
137. d to the injured fabric of the raft Ensure that each coat is thoroughly dry before applying the next coat To aid in adhesion prior to applying the patch the inside area to be repaired and cemented surface of the patch should be cleaned with a cloth moistened with rubber solvent The cement will then become tacky Apply the patch Fold the patch lengthwise in the shape of the letter U and insert the patch between the torn edges of the injury on the life rafts Position the patch so that the fabric at the end of the tear will coincide with a cross line and the center line on the patch follows one edge of the torn fabric Attach one edge of the torn fabric along the center line on the patch Inspect the repair for wrinkles Working from the attached edge of the fabric to the edge of the patch remove the wrinkles with a stitcher Lay the opposite edge of the torn fabric on the patch so that it butts the edge of the torn fabric that has already been applied to the patch Remove the wrinkles Thoroughly roll the patch with a 2 inch rubber roller AC 43 13 1B Prepare and attach the outside patch as outlined in OUTSIDE PATCHES sub paragraphs 9 42b 1 a e Allow to cure for at least 60 hours before performing leak tests and storing Seams and Tapes Remove all old or dead cement from the area that will require recementing Dampen the repair area with a solvent moistened cloth then roll or rub off the old cemen
138. data bus DEMOD demodulator DEMUX demultiplexer DFDR 4igital flight data recorder DG directional gyro DGTL igital DH decision height DISC SOL disconnect solenoid DISC disconnect DISTR distribution DMA direct memory access DMB dead main bus DMC display management computer DME distance measuring equipment DMEA distance measuring equipment antenna DN down DU display unit E E or E amp E electrical electronic E1 1 first shelf number 1 equipment rack E2 2 second shelf number 2 equipment rack EADE electronic automatic direction finder EADI electronic attitude director indicator EAROM electrically alterable read only memory EC EICAS computer ECAM electronic centralized aircraft monitoring EDSP EICAS display select panel EDU EICAS display unit EEC electronic engine control EFI electronic flight instrument EFIS electronic flight instrument system EFISCP EFIS control panel EFISCU EFIS comparator unit EFISG EFIS symbol generator EFISRLS EFIS temote light sensor EHSI electronic horizontal situation indicator EHSID electronic horizontal situation indicator display EHS V electrohydraulic servo value EICAS engine indicating and crew alerting system ELCU electrical load control unit ELEC electric electronic ELECT electrical ELEX electronics electrical ELT mergency Locator Transmitter EMER GE
139. ded practices DETERMINATION OF CIRCUIT BREAKER RATINGS Circuit protection devices must be sized to supply open circuit capability A circuit breaker must be rated so that it will open before the current rating of the wire attached to it is exceeded or before the cumulative rating of all loads connected to it are exceeded whichever is lowest A circuit breaker must always open before any component downstream can overheat and generate smoke or fire Wires must be sized to carry continuous current in excess of the circuit protective device rating including its time current characteristics and to avoid excessive voltage drop Refer to section 5 for wire rating methods DC CIRCUIT PROTECTOR CHART Table 11 3 may be used as a guide for the selection of circuit breaker and fuse rating to protect copper conductor wire This chart was prepared for the conditions specified If actual conditions deviate materially from those stated ratings above or below the values recommended may be justified For example a wire run individually in the open air may possibly be protected by the circuit breaker of the next higher rating to that shown on the chart In general the chart is conservative for all ordinary aircraft electrical installations Page 11 496 TABLE 11 3 DC wire and circuit protector chart Wire AN gauge copper Circuit breaker amp Fuse amp Basis of chart 1 Wire bundles in 135 F ambient and altitudes up to 30 000 feet
140. ders have an underwater acoustic beacon mounted on its front panel which must be returned to their respective manufacturer s for battery servicing For maintenance information refer to the equipment or aircraft manufacture s maintenance instruction manual COCKPIT VOICE RECORDERS CVR CVR s are very similar to flight data recorders They look nearly identical and operate in almost the same way CVR s monitors the last 30 minutes of flight deck conversations and radio communications The flight deck conversations are recorded via the microphone monitor panel located on the flight deck This panel is also used to test the system and erase the tape if so desired Before operating the erase CVR mode consult the operational manual of the manufacturer for the CVR Playback is possible only after the recorder is removed from the aircraft Refer to the specific equipment manufacturer s manuals and procedures Par 12 22 AC 43 13 1B The Solid State Cockpit Voice Recorder system is composed of three essential components a solid state recorder a control unit remote mic amplifier and an area microphone Also installed on one end of the recorder is an Under water Locator Beacon ULB The recorder accepts four separate audio inputs pilot copilot public address third crew member and cockpit area microphone and where applicable rotor speed input and flight data recorder synchronization tone input For maintenance informati
141. distinct hissing sound of escaping gas If this check proves negative it will be necessary to soap test all lines and connections with a castile soap and water solution or specially compounded leak test material Make the solution thick enough to adhere to the contours of the fittings At the completion of the leakage test remove all traces of the soap and water CAUTION Do not attempt to tighten any connections while the system is charged Regulators Valves and Gauges Line maintenance of oxygen regulators valves and gauges does not include major repair These components are precision made and their repair usually requires the attention of a repair station or the manufacturer Care must be taken when reinstalling these components to Par 9 49 Page 9 452 AC 43 13 1B ascertain if the threaded area is free of nicks burrs and contaminants that would prevent the connections from sealing properly CAUTION Do not use petroleum lubricants on these components Masks and Hoses Troubleshooting If a mask assembly is defective leaks does not allow breathing or contains a defective microphone it is advisable to return the mask assembly to the manufacturer or a repair station Maintenance Practice and Cleaning Clean and disinfect the mask assemblies after use as appropriate NOTE Use care to avoid damaging the microphone assembly while cleaning and sterilizing Wash the mask with a mild soap solution and rin
142. dius Never pull on coaxial cable except in a straight line Never use coaxial cable for a handle lean on it or hang things on it or any other wire WITH NORMAL HAND PRESSURE FIGURE 11 9 Slack between supports MOISTURE PROTECTION WHEEL WELLS AND LANDING GEAR AREAS Wires located on landing gear and in the wheel well area can be exposed to many hazardous conditions if not suitably protected Where wire bundles pass flex points there must not be any strain on attachments or excessive slack when parts are fully extended or retracted The wiring and protective tubing must be Par 11 115 inspected frequently and replaced at the first sign of wear Wires should be routed so that fluids drain away from the connectors When this is not practicable connectors must be potted Wiring which must be routed in wheel wells or other external areas must be given extra protection in the form of harness jacketing and connector strain relief Conduits or flexible sleeving Page 11 533 9 8 98 AC 43 13 1B used to protect wiring must be equipped with drain holes to prevent entrapment of moisture PROTECTION AGAINST PERSONNEL AND CARGO Wiring must be installed so the structure affords protection against its use as a handhold and damage from cargo Where the structure does not afford adequate protection conduit must be used or a suitable mechanical guard must be provided HEAT PRECAUTIONS Wiring must be routed away f
143. e ANSI EIA 5200000 specifies that contact separations greater than 10 microseconds and that closing of open contacts in excess of 1 microsecond are failures Repeated contact separations during high levels of vibration or shock may cause excessive electrical degradation of the contacts These separations can also cause false signals to be registered by electronic data processors without proper buffering Although proximity switches do not have moving parts the reliability of the internal electronic parts of the switch may be reduced Reliability and mean time between failure MTBF calculations should reflect the applicable environment Note that the mounting of both the proximity sensor and its target must be rigid enough to withstand shock or vibration to avoid creating false responses Electromagnetic Radio Interference EMI RFI Frequency DC operated electromechanical switches are usually not susceptible to EMI RFI Proximity switches are susceptible to an EMI RFI environment and must be evaluated in the application Twisting lead wires metal overbraids lead wire routing and the design of the proximity switch minimize susceptibility Par 11 53 AC 43 13 1B The arcing of electromechanical switch contacts generates short duration EMI RFI when controlling highly inductive electrical loads Twisting lead wires metal overbraids and lead wire routing can reduce or eliminate generation problems when dealing with
144. e fire resistant qualities 9 65 9 70 RESERVED Page 20 457 Par 10 1 9 8 98 AC 43 13 1B CHAPTER 10 WEIGHT AND BALANCE SECTION 1 TERMINOLOGY GENERAL The removal or addition of equipment results in changes to the center of gravity c g The empty weight of the aircraft and the permissible useful load are affected accordingly Investigate the effects of these changes since the aircraft flight characteristics may be adversely affected Information on which to base the record of weight and balance changes to the aircraft may be obtained from the pertinent Aircraft Specifications Type Certificate Data Sheet TCDS prescribed aircraft operating limitations aircraft flight manual aircraft weight and balance report and maintenance manual Removal or addition of minor items of equipment such as nuts bolts rivets washers and similar standard parts of negligible weight on fixed wing aircraft do not require a weight and balance check Rotorcraft are in general more critical with respect to control with changes in the c g position The procedures and instructions in that particular model s maintenance or flight manual should be followed TERMINOLOGY The following terminology is used in the practical application of weight and balance control Maximum Weight The maximum weight is the maximum authorized weight of the aircraft and its contents as listed in the specifications Empty Weight The empty weigh
145. e or have a successful history of such usage Explanations of the various insulation materials mentioned in table 11 11 by abbreviations can be found in the glossary OPEN AIRFRAME INTERCONNECTING WIRE Interconnecting wire is used in point to point open harnesses normally in the interior or pressurized fuselage with each wire providing enough insulation to resist damage from handling and service exposure See table 11 11 Electrical wiring is often installed in aircraft without special enclosing means This practice is known as open wiring and offers the advantages of ease of maintenance and reduced weight PROTECTED WIRE Airborne wire that is used within equipment boxes or has additional protection such as an exterior jacket conduit tray or other covering is known as protected wire See table 11 12 SEVERE WIND AND MOISTURE PROBLEMS SWAMP Areas such as wheel wells wing fold and pylons flap areas and those areas exposed to extended weather shall dictate selection and will require special consideration Insulation or jacking will vary according to the environment Suitable wire types selected from MIL W 22759 shall be used in these applications See table 11 11 Page 11 520 Suitable wire types selected from MIL W 22759 are preferred for areas that require repeated bending and flexing of the wire Consideration should be made to areas that require frequent component removal or repair See table 11 11
146. e and iene for Synthetic fluids SKYDROL 005 inches to 031 clear and orHYJET product Fora ance between nipple hex and lubricant during assembly use socket a vegetable soap liquid DISASSEMBLE IN REVERSE ORDER FIGURE 9 8 Hose assembly instructions can be used for low pressure hydraulic fluid and oil line applications Par 9 30 Page 9 431 9 8 98 TABLE 9 3 Aircraft hose specifications SINGLE WIRE BRAID FABRIC COVERED MIL TUBE HOSE PART NO SIZE SIZE MIL H 8794 3 L MIL H 8794 4 L MIL H 8794 5 L MIL H 8794 6 L MIL H 8794 8 L MIL H 8794 10 L MIL H 8794 12 L MIL H 8794 16 L MIL H 8794 20 L MIL H 8794 24 L MIL H 8794 32 L MIL H 8794 40 L MIL H 8794 48 L Construction Seamless synthetic rubber inner tube reinforced with one fiber braid one braid of high tensile steel wire and covered with oil resistant rubber impregnated fiber braid AC 43 13 1B RECOMM MIN MAX MIN OPER BURST PROOF BEND PRESS PRESS PRESS RADIUS Uses Hose is approved for use in aircraft hydraulic pneumatic coolant fuel and oil systems Operating Temperatures Sizes 3 through 12 Minus Identification Hose is identified by 65 F to plus 250 F specification number size number quarter year and year hose manufacturers identification Sizes 16 through 48 Minus 40 F to plus 275 F Note Maximum temperatures and pressures should not be used simultaneously MULTIPLE WIRE BRAID RUBB
147. e by the original parachute manufacturer or by a qualified parachute rigger certificated in accordance with 14 CFR part 65 The lead seal should be inspected periodically to ensure the thread has not been broken If broken or broken and retied or 9 8 98 appears to have been tampered with the parachute must be repacked by a properly certified rigger Safety Belts All seat belts and restraint systems must conform to standards established by the FAA These standards are contained in Technical Standard Order TSO C22 for seat belts and TSO C114 for restraint systems Safety belts eligible for installation in aircraft must be identified by the proper TSO markings on the belt Each safety belt must be equipped with an approved metal to metal latching device Airworthy type certificated safety belts currently in aircraft may be removed for cleaning reinstalled However when a TSO safety belt is found unairworthy replacement with a TSO approved belt or harness is required The webbing of safety belts even when mildew proofed is subject to deterioration due to constant use cleaning and the effects of aging Fraying of belts is an indication of wear and such belts are likely to be unairworthy because they can no longer hold the minimum required tensile load OXYGEN SYSTEMS The following instructions are to serve as a guide for the inspection and maintenance of aircraft oxygen systems The information is applicab
148. e colors Current military specification multi conductor cables in accordance with MIL C 27500 use White Blue Orange for the initial three colors Use of an alternative color code during modification without adequate notation on wiring diagrams could severely complicate subsequent servicing of the aircraft At the time of this writing MIL C 27500 is being revised to include the older color sequence and could eliminate this problem in the future 11 79 11 84 RESERVED Page 11 519 and 11 38 Par 11 85 9 8 98 AC 43 13 1B SECTION 7 TABLE OF ACCEPTABLE WIRES AIRCRAFT WIRE TABLE Tables 11 11 and 11 12 list wires used for the transmission of signal and power currents in aircraft It does not include special purpose wires such as thermocouple engine vibration monitor wire fiber optics data bus and other such wire designs Fire resistant wire is included because it is experiencing a wider application in aircraft circuits beyond that of the fire detection systems All wires in tables 11 11 and 11 12 have been determined to meet the flammability requirements of Title 14 of the Code of Federal Regulation 14 CFR part 25 section 25 869 a 4 and the applicable portion of part 1 of Appendix F of part 25 The absence of any wire from tables 11 11 and 11 12 are not to be construed as being unacceptable for use in aircraft However the listed wires have all been reviewed for such use and have been found suitabl
149. e inflator stem gaskets and check the stem caps for tightness Ensure that the inflator is centered on the stem Check rescue light Inspect and test 9 8 98 Replace the battery if it shows any signs of encrustation Inspect for proper installation and physical condition of the lamp wire and battery Check the light assembly for proper operation and water insulation and flotation Pull the sealing plug where applicable from the battery Let water flow through the open ports Make sure the battery is activated and power is supplied to the light Fill out the inspection record and serviceable parts tag Attach to the vest Deflate the life preserver and repack in container and secure The accessories listed below will be required for all life preservers One Recognition Light Remove when returning to serviceable or reparable storage Remove for replacement of defective light repair or salvage of preserver One Recognition Light Battery Remove when returning to serviceable or reparable storage Record the inspection data on data cards Life preserver inspected and found sea worthy Include the inspector s signature Inspection record Upon completion of 12 month inspection and tests each flotation cell will be marked to indicate the date the inspection was accomplished The inspection stencil will consist of 1 8 inch letters and numerals and will be applied to the patches on the cells example 4 3 97 To
150. e package is stenciled repair plugs and pliers with letters not less than 1 2 inch high Par 9 49 Page 9 440 9 8 98 Signal Flares Check the flares for obvious damage suspended lot numbers Replace if lot number is over age or obvious damage exists Carrying Case Check for snags abrasions and defective snaps Repair or replace as necessary Locator Beacon and Battery Check for corrosion and obvious damage per the manufacturer s manual Assemble as an operating unit Perform an operational test prepare the beacon for water activation by pulling out the battery switch plug from the end of the transmitter section and package as instructed on the container Lines and Anchor Check all lines and sea anchors for conditions and security Police Whistle Inspect and test Flashlight Test the flashlight switch for operation remove old batteries and inspect the case for corrosion and condition and install new batteries and test momentarily for operation Space Blankets Check space blankets if required for rips tears and obvious damage Light sticks Inspect light sticks for condition and check expiration date Solar Still Kit condition Check the solar still kit for Par 9 39 Page 9 441 AC 43 13 1B Survival Manual Inspect the survival manual for condition and completeness 9 8 98 AC 43 13 1B Duct Tape Check the duct tape for deterioration Plastic Trash Bags Assure that thr
151. e replaced In fact some indicator designs are 9 8 98 such that the indicator cannot be reset unless the filter bowl is removed and the element replaced Flushing a Hydraulic System When inspection of hydraulic filters or hydraulic fluid evaluation indicates that the fluid is contaminated flushing the system may be necessary This must be done according to the manufacturer s instructions however typical procedure for flushing is as follows Connect a ground hydraulic test stand to the inlet and outlet test ports of the system Verify that the ground unit fluid is clean and contains the same fluid as the aircraft Change the system filters Pump clean filtered fluid through the system and operate all subsystems until no obvious signs of contamination are found during inspection of the filters Dispose of contaminated fluid and filter Note A visual inspection of hydraulic filters is not always effective Disconnect the test stand and cap the ports Ensure that the reservoir is filled to the FULL line or proper service level Inspections Hydraulic and pneumatic systems are inspected for leakage worn or damaged tubing worn or damaged hoses wear of moving parts security of mounting for all units safetying and any other condition specified by the maintenance manual A complete inspection includes considering the age cure date stiffness of the hose and an operational check of all subsystems Leakage from a
152. e the manner in which these inspections are to be accomplished Additional information is also available in AC 20 37D Aircraft Metal Propeller Maintenance Steel Blade Inspection The inspection of steel blades may be accomplished by either visual fluorescent penetrant see chapter5 or magnetic particle inspection The visual inspection is easier if the steel blades are covered with engine oil or rust preventive compound The full length of the leading edge especially near the tip the full length of the trailing edge the grooves and shoulders on the shank and all 9 8 98 dents and scars should be examined with a magnifying glass to decide whether defects are scratches or cracks Aluminum Propellers and Blades Carefully inspect aluminum propellers and blades for cracks and other flaws A transverse crack or flaw of any size is cause for rejection Multiple deep nicks and gouges on the leading edge and face of the blade is cause for rejection Use dye penetrant or fluorescent dye penetrant to confirm suspected cracks found in the propeller Refer any unusual condition or appearance revealed by these inspections to the manufacturer Limitations Corrosion may be present on propeller blades in varying amounts Before performing any inspection process maintenance personnel must examine the specific type and extent of the corrosion See chapter 6 and or refer to AC 43 4A Corrosion Control For Aircraft Corrosion other tha
153. e weight of this airplane is 2000 Ibs and the arm from the datum to the center of gravity is 16 inches the moment of the aircraft about the datum is 2000 x 16 or 32 000 in Ibs FIGURE 10 3 Example of moment computation datum The c g of the loaded aircraft must be within these limits at all times as illustrated in figure 10 7 Mean Aerodynamic Chord MAC The MAC is established by the manufacturer who defines its leading edge and its trailing edge in terms of inches from the datum The c g location and various limits are then expressed in percentages of the chord The Par 10 2 Page 10 461 location and dimensions of the MAC can be found in the Aircraft Specifications the TCDS the aircraft flight manual or the aircraft weight and balance report Weighing Point If the c g location is determined by weighing it is necessary to obtain horizontal measurements between the points on the scale at which the aircraft s weight is concentrated If weighed using 9 8 98 NOSE WHEEL TYPE AIRCRAFT DATUM LOCATED FORWARD OF THE MAIN WHEELS NOSE WHEEL TYPE AIRCRAFT DATUM LOCATED AFT OF THE MAIN WHEELS C G D LAC AC 43 13 1B TAIL WHEEL TYPE AIRCRAFT DATUM LOCATED FORWARD OF THE MAIN WHEELS C G D 8 TAIL WHEEL AIRCRAFT DATUM LOCATED AFT OF THE MAIN WHEELS C G D RXC C G Distance from datum to center of gravity of the aircraft W The weight of the aircraft at the time of we
154. ead cutout and the wire bundle a suitable grommet should be installed as indicated in figure 11 14 The grommet may be cut at a 45 degree angle to facilitate installation provided it is cemented in place and the slot is located at the top of the cutout WIRE AND CABLE CLAMPS INSPECTION Inspect wire and cable clamps for proper tightness Where cables pass through structure or bulkheads inspect for proper clamping and grommets Inspect for sufficient slack between the last clamp and the electronic equipment to prevent strain at the cable terminals and to minimize adverse effects on shock mounted equipment 9 8 98 AC 43 13 1B 9 9 CABLE CLAMP OR EQUIVALENT MS 27039 NAS 603 SCREW AN 9368 LOCKWASHER EXTERNAL TEETH MS 21044 NUT MS 35338 SELF LOCKING LOCKWASHER AN 340 NUT SPLIT FIGURE 11 12 Typical mounting hardware for MS 21919 cable clamps Par 11 146 Page 11 539 9 8 98 AC 43 13 1B MS 21919 CABLE CLAMPS ANGLE MEMBER 7 MEMBER CORRECT ANGLE BRACKET WIRE IS PINCHED IN CLAMP INCORRECT FIGURE 11 13 Installing cable clamp to structure Par 11 147 Page 11 540 9 8 98 AC 43 13 1B A CUSHION CLAMP AT MS21919 BULKHEAD HOLE CABLE CLAMP CLEARANCE 3 8 MINIMUM WY WIRES LESS THAN 3 8 INCH 4 lt FROM HOLE EDGE ANGLE BRACKET WITH TWO POINT FASTENING MS21919 CABLE CLAMP CUSHION CLAMP AT BULKHEAD HOLE WITH MS35489 GROMMET CUSHION CLAMP AT BULKHEAD HOLE WITH M
155. eans and through mechanical linkages actuates electrical conductors contacts that control electrical circuits Solid state relays may also be used in electrical switching applications Par 11 53 AC 43 13 1B Use of Relays Most relays are used as a switching device where a weight reduction can be achieved or to simplify electrical controls It should be remembered that the relay is an electrically operated switch and therefore subject to dropout under low system voltage conditions Types of Connections Relays are manufactured with various connective means from mechanical to plug in devices Installation procedures vary by the type of connection and should be followed to ensure proper operation of the relay Repair Relays are complicated electromechanical assemblies and most are not repairable Relay Selection Contact ratings as described on the relay case describe the make carry and break capability for resistive currents only Consult the appropriate specification to determine the derating factor to use for other types of current loads Ref MIL PRF 39016 MIL PRF 5757 MIL PRF 6016 MIL PRF 835836 Operating a relay at less than nominal coil voltage may compromise its performance and should never be done without written manufacturer approval Relay Installation and Maintenance For installation and maintenance care should be taken to ensure proper placement of hardware especially at electrical connections
156. ected station to the aircraft using an appropriate chart Observe the ADF relative bearing reading and compare to the chart Slew the needle and observe how fast or slowly it returns to the reading ADF performance may be degraded by lightning activity airframe charging ignition noise and atmospheric phenomena INSTRUMENT LANDING SYSTEMS ILS The ILS consist of several components such as the localizer glide slope marker beacon radio altimeter and DME Localizer and glide slope receivers and marker beacons will be discussed in this section Localizer receiver operates on one of 40 ILS channels within the frequency range of 108 10 to 111 95 MHz These signals provide course guidance to the pilot to the runway centerline through the lateral displacement of the VOR localizer LOC deviation indicator The ground transmitter is sighted at the far end of the runway and provides a valid signal from a distance of 18 NM from the transmitter The indication gives a full fly left right deviation of 700 feet at the runway threshold Identification of the transmitter is in International Morse Code and consists of a three letter identifier preceded by the Morse Code letter I two dots The localizer function is usually integral with the VOR system and when maintenance is performed on the VOR unit the localizer is also included The accuracy of the system can be effectively evaluated through normal flight operations if evaluated during visual
157. ectrical clearance and creepage distance along surfaces between adjacent terminals at different potentials and between these terminals and adjacent ground surfaces are adequate for the voltages involved 9 8 98 AC 43 13 1B TABLE 11 14 Stud bonding or grounding to flat surface SCREW OR BOLT WASHER A B LOCK WASHER 2 ioe STRUCTURE V LOCKNUT WASHER B WASHER D TERMINAL O4 10 4 LOCKWASHER F Aluminum Terminal and Jumper Screw or Bolt and Lock nut Cadmium Plated steel Aluminum Alloys Cadmium Plated Steel Magnesium Alloys Cadmium Plated Steel Steel Cadmium Plated Corrosion Resisting Steel Steel Corrosion Resisting Cadmium Plated Steel Aluminum Alloys Magnesium Alloys Cadmium Plated Steel Steel Cadmium Plated Corrosion Resisting Steel Steel Corrosion Resisting Aluminum Alloy Cadmium Plated Steel Cadmium Plated Steel Magnesium Alloy Cadmium None Plated Steel Cadmium Plated Steel Washer B Aluminum Alloy Magnesium Alloy None Washer C amp D Cadmium Plated Steel or Aluminum Cadmium Plated Steel or Aluminum Cadmium Plated Steel or Aluminum Cadmium Plated Steel or Aluminum Tinned Copper Terminal and Jumper Aluminum Alloy Cadmium Plated Steel Cadmium Plated Steel Corrosion Resisting Steel Aluminum Alloy Cadmium Plated Steel Cadmium Plated Steel Cadmium Plated
158. ed current or the battery is being discharged at the 5 minute rate The tabulation shown in table 11 6 defines the maximum acceptable voltage drop in the load circuits between the bus and the utilization equipment ground Resistance The resistance of the current return path through the aircraft structure is generally considered negligible However this is based on the assumption that adequate TABLE 11 7 Examples of determining required wire size using figure 11 2 Check calculated voltage drop Resistance Run Circuit Lengths Current Ft Length Current 1 volt 100 feet 20 No 6 000445 amps ohms ft Page 11 502 TABLE 11 6 Tabulation chart allowable voltage drop between bus and utilization equipment ground Nominal system voltage Allowable voltage drop continuous operation Intermittent operation bonding to the structure or a special electric current return path has been provided that is capable of carrying the required electric current with a negligible voltage drop To determine circuit resistance check the voltage drop across the circuit If the voltage drop does not exceed the limit established by the aircraft or product manufacturer the resistance value for the circuit may be considered satisfactory When checking a circuit the input voltage should be maintained at a constant value Tables 11 7 and 11 8 show formulas that may be used to determine electrical resistance in wires and
159. ed for frequent disconnection Use of aluminum wire is also discouraged for runs of less than three feet Termination hardware should be of the type specifically designed for use with aluminum conductor wiring INSTRUCTIONS FOR USE OF ELECTRICAL WIRE CHART Correct Size To select the correct size of electrical wire two major requirements must be met The wire size should be sufficient to prevent an excessive voltage drop while carrying the required current over the required distance See table 11 6 Tabulation Chart for allowable voltage drops The size should be sufficient to prevent overheating of the wire carrying the required current See paragraph 11 69 for allowable current carrying calculation methods Two Requirements To meet the two requirements see paragraph 11 66b in selecting the correct wire size using figure 11 2 or figure 11 3 the following must be known The wire length in feet The number of amperes of current to be carried The allowable voltage drop permitted Par 11 67 Page 11 508 AC 43 13 1B The required continuous intermittent current The estimated or measured conductor temperature Is the wire to be installed in conduit and or bundle Is the wire to be installed as a single wire in free air Example No 1 Find the wire size in figure 11 2 using the following known information The wire run is 50 feet long including the ground wire Current load is 20 amps
160. ed for electronic equipment to provide radio frequency return circuits and for most electrical equipment to facilitate reduction in EMI The cases of components which produce electromagnetic energy should be grounded to structure To ensure proper operation of electronic equipment it is particularly important to conform the system s installation specification when interconnections bonding and grounding are being accomplished Metallic Surface Bonding All conducting objects on the exterior of the airframe must be electrically connected to the airframe through mechanical joints conductive hinges or bond straps capable of conducting static charges and lightning strikes Exceptions may Par 11 186 Page 11 553 AC 43 13 1B be necessary for some objects such as antenna elements whose function requires them to be electrically isolated from the airframe Such items should be provided with an alternative means to conduct static charges and or lightning currents as appropriate Static Bonds All isolated conducting parts inside and outside the aircraft having an area greater than 3 and a linear dimension over 3 inches that are subjected to appreciable electrostatic charging due to precipitation fluid or air in motion should have a mechanically secure electrical connection to the aircraft structure of sufficient conductivity to dissipate possible static charges A resistance of less than 1 ohm when clean and dry will general
161. ed with the same type and color of tying materials ELECTROMAGNETIC INTERFERENCE EMI Wiring of sensitive circuits that may be affected by EMI must be routed away from other wiring interference or provided with sufficient shielding to avoid system malfunctions under operating conditions EMI between susceptible wiring and wiring which is a source of EMI increases in proportion to the length of parallel runs and decreases with greater separation EMI should be limited to negligible levels in wiring related to critical systems that is the function of the critical system should not be affected by the EMI generated by the adjacent wire Use of shielding with 85 percent coverage or greater is recommended Coaxial triaxial twinaxial or quadraxial cables should be used wherever appropriate with their shields connected to ground at a single point or multiple points depending upon the purpose of the shielding The airframe Par 11 104 Page 11 529 AC 43 13 1B grounded structure may also be used as an EMI shield INTERFERENCE TESTS Perform an interference test for installed equipment and electrical connections as follow The equipment must be installed in accordance with manufacturer s installation instructions Visually inspect all the installed equipment to determine that industry standard workmanship engineering practices were used Verify that all mechanical and electrical connections have been properly made and that
162. ee each plastic trash bags are serviceable Accessory Containers Check the containers for condition and security Repack the accessories secure and record the inspection data on data cards Record the Inspection date Dye Marker Check for dents and overall condition Shark Chaser Check for dents and overall condition After Inspection Replace accessories in the container close and tie securely with tying tapes Draw a 25 pound breaking strength cord tightly around the center and one approximately 5 inches from each end of the container tie with square knots and seal with a lead seal Folding Life Rafts Fold the life rafts per the manufacturer s folding diagram using soapstone and secure the raft in its container Check the container for obvious damage SPECIAL INSPECTIONS Life rafts in storage or in service shall be unpacked and thoroughly inspected for mildew whenever weather or other conditions warrant The extent of a special inspection will be determined by the inspector or maintenance chief following a review of the circumstances or conditions to which the life rafts have been subjected The inspector or maintenance chief may direct a complete overall inspection and inflation test Par 9 39 Page 9 442 9 8 98 of the life rafts regardless of the last date of inspection if it is considered that another inspection is warranted INSPECTION RECORD The date the inspection was completed will be stencile
163. een exposed to electrolyte or on which the insulation appears to be or is suspected of being in an initial stage of deterioration due to the effects of electrolyte 9 8 98 Check wiring that shows evidence of overheating even if only to a minor degree for the cause of the overheating Wiring on which the insulation has become saturated with engine oil hydraulic fluid or another lubricant Wiring that bears evidence of having been crushed or severely kinked Shielded wiring on which the metallic shield is frayed and or corroded Cleaning agents or preservatives should not be used to minimize the effects of corrosion or deterioration of wire shields Wiring showing evidence of breaks cracks dirt or moisture in the plastic sleeves placed over wire splices or terminal lugs Sections of wire in which splices occur at less than 10 foot intervals unless specifically authorized due to parallel connections locations or inaccessibility When replacing wiring or coaxial cables identify them properly at both equipment power source ends Testing of the electrical and chemical integrity of the insulation of sample wires taken from areas of the aircraft that have experienced wiring problems in the past can be used to supplement visual examination of the wire The test for chemical integrity should be specific for the degradation mode of the insulation If the samples fail either the electrical or chemical integrity tests then t
164. elieve the pressure If the pressure is satisfactory return the raft to service in accordance with the procedure outlined Inspect the CO cylinder for evidence of cross threading or stripping Inspect the CO bottle inflation valve cable rigging as follows Remove the screws that attach the cover plate to the valve and remove the cover plate Inspect the firing line cable ball swage for engagement in the correct recess for either Upward Pull or Downward Pull The cable will be wrapped around the sheave approximately 270 degrees Reposition the cable ball swage as required See figure 9 12 Replace the cover plate The green dot on the sheave should be visible through the window in the cover plate indicating a charged cylinder Check the CO cylinder release cable and housing for condition and security Par 9 37 Page 9 437 AC 43 13 1B Make sure the safety deflector is removed from the cylinder outlet before connecting the cylinder to the raft See figure 9 12 Stencil the life raft s inspection date on the raft SURVIVAL KIT INSPECTION Survival Kit Contents Each raft passengers or crew members minimum the following accommodating should contain as a Hand Pump if required Desalting Kit First Aid Kit Mirror Reflector Emergency Rations Tarpaulins Fishing Kit Raft Knife Compass Protective Ointment Sunburn Oars Emergency Water Containers Repair Kits Signal Flares Carrying Case
165. emove the ELT from the mount and inspect the mounting hardware for proper installation and security Reinstall the ELT into its mount and verify the proper direction for crash activation Reconnect all cables They should have some slack at each end and should be properly secured to the airplane structure for support and protection Battery Corrosion Gain access to the ELT battery and inspect No corrosion should be detectable Verify the ELT battery is approved and check its expiration date Operation of the Controls and Crash Sensor Activate the ELT using an applied force Consult the ELT manufacturer s instructions before activation The direction for mounting and force activation is indicated on the ELT A TSO C91 ELT can be activated by using a quick rap with the palm A TSO C91a ELT can be activated by using a rapid forward throwing motion coupled by a rapid reversing action Verify that the ELT can be activated using a watt meter the airplane s VHF radio communications receiver tuned to 121 5 MHz or other means see NOTE 1 Insure that the G switch has been reset if applicable For a Sufficient Signal Radiated From its Antenna Activate the ELT using the ON or ELT TEST switch A low quality Page 12 606 9 8 98 AM broadcast radio receiver should be used to determine if energy is being transmitted from the antenna When the antenna of the AM broadcast radio receiver tuning dial on any setting is held about 6 inches
166. en the tongues of terminal lugs Aluminum Terminal Lugs The aluminum terminal lugs conforming to MIL T 7099 MS 25435 MS 25436 MS 25437 and MS 25438 should be crimped to aluminum wire only The tongue of the aluminum terminal lugs or the total number of tongues of aluminum terminal lugs when stacked should be sandwiched between two MS 25440 flat washers when terminated on terminal studs Spacers or washers should not be used between the tongues of terminal lugs Special attention should be given to aluminum wire and cable installations to guard against conditions that would result in excessive voltage drop and high resistance at junctions that may ultimately lead to failure of the junction Examples of such conditions are improper installation of terminals and washers improper torsion torquing of nuts and inadequate terminal contact areas Class 2 Terminal Lugs The Class 2 terminal lugs conforming to MIL T 7928 may be used for installation provided that in such installations Class 1 terminal lugs are adequate for replacement without rework of installation or terminal lugs Class 2 terminal lugs should be the insulated type unless the conductor temperature exceeds 105 C In that case uninsulated terminal lugs should be used Par 11 176 AC 43 13 1B Parts lists should indicate the appropriate Class 1 terminal lugs to be used for service replacement of any Class 2 terminal lugs installed Termination of Shielded
167. ers Installation cabling should be kept as short as possible except for antenna cables which are usually precut or have a specific length called out at installation Proper bonding on the order of 0 003 ohms is very important to the performance of avionics equipment Page 12 601 Check to assure that the radios and instruments are secured to the instrument panel Check that all avionics are free of dust dirt lint or any other airborne contaminates there is a forced air cooling system it must be inspected for proper operation Equipment ventilation openings must not be obstructed Check the microphone headset plugs and connectors and all switches and controls for condition and operation Check all avionics instruments for placards Check lightening annunciator lights and cockpit interphone for proper operation The circuit breaker panel must be inspected for the presence of placarding for each circuit breaker installed Check the electrical circuit switches especially the spring load type for proper operation An internal failure in this type of switch may allow the switch to remain closed even though the toggle or button returns to the OFF position During inspection attention must be given to the possibility that improper switch substitution may have been made Check antennas for broken or missing antenna insulators lead through insulators springs 9 8 98 safety wires cracked antenna housings
168. es or undulations welding a materials joining process used in making welds welding rod a form of welding filler metal normally packaged in straight lengths welding torch the device used in gas welding wood decay disintegration of wood substance through the action of wood destroying fungi 625 9 8 98 wood decay incipient the early stage of decay in which the disintegration has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood wood decay typical or advanced the stage of decay in which the disintegration is readily recognized because the wood has become punky soft and spongy stringy pitted or crumbly x ray a radiographic test method used to detect internal defects in a weld AC 43 13 1B Appendix 1 XL ETFE A process of radiation cross linking the polymer chains is used to thermally set the plastic This prevents the material from softening and melting at elevated temperature XL Polyalkene an insulation material based on the polyolefin family that has its normally thermomelt characteristic altered by the radiation cross linking process to that of a nonmelt therm set material 626 9 8 98 AC 43 13 1B Appendix 2 APPENDIX 2 ACRONYMS AND ABBREVIATIONS The acronyms and abbreviations listed are some of many that are likely to be encountered by the aviation mechanic or technician involved in the maintenance of aircraft 429 ARINC 4
169. ethod of corrosion protection in which a surface is plated with a metal less noble than itself Any corrosion will attack the plating rather than the base metal sandwich construction a __ structural panel concept consisting in its simplest form of two relatively thin parallel sheets face sheets of structural material bonded to and separated by a relatively thick lightweight core High strength to weight ratios are obtained with sandwiched materials scarf joint a joint made by cutting away similar angular segments of two adherents and bonding the adherents with cut areas fitted together Score a surface tear or break on a surface that has a depth and length ranging between a scratch and a gouge scratch a superficial small cut on a surface AC 43 13 1B Appendix 1 semiconductor device any device based on either preferred conduction through a solid in one direction as in rectifiers or on a variation in conduction characteristics through a partially conductive material as in a transistor severe wind and moisture problem SWAMP areas areas such as wheel wells wing folds and near wing flaps and areas directly exposed to extended weather conditions are considered SWAMP areas on aircraft silicone rubber a high temperature 200 C plastic insulation that has a substantial silicone content soldering a group of welding processes that produces coalescence of materials by heating them to the soldering
170. f connections to fuse holders Page 11 526 9 8 98 Inspect for the presence of corrosion and evidence of overheating on fuses and fuse holders Replace corroded fuses and clean fuse holders If evidence of overheating is found check for correct rating of fuse Check mounting security of fuse holder Inspect for replenishment of spare fuses used in flight Replace with fuses of appropriate current rating only Inspect for exposed fuses susceptible to shorting Install cover of nonconducting material if required CONNECTORS Ensure reliability of connectors by verifying that the following conditions are met or that repairs are effected as required Inspect connectors for security and evidence of overheating cause of over heating must be corrected and exteriors for corrosion and cracks Also wires leading to connectors must be inspected for deterioration due to overheating Replace corroded connections and overheated connectors Ensure installation of cable clamp reference MIL C 85049 adapters on applicable MS connectors except those that are moisture proof See that silicone tape is wrapped around wires in MS3057 cable clamp adapters so that tightening of the cable clamp adapter cap provides sufficient grip on the wires to keep tension from being applied to the connector pins Make sure unused plugs and receptacles are covered to prevent inclusion of dust and moisture Receptacles should have metal Par 11 99 A
171. gainst one another and are correctly secured and clamped Replacement of Metal Lines When inspection shows a line to be damaged or defective replace the entire line or if the damaged section is localized a repair section may be inserted In replacing lines always use tubing of the same size and material as the original line Use the old tubing as a template in bending the new line unless it is too greatly damaged in which case a template can be made from soft iron wire Soft aluminum tubing 1100 3003 or 5052 may also be used as a template For forming of all tubing use an acceptable hand or power tube bending tool Bend tubing carefully to avoid excessive flattening kinking or wrinkling Minimum bend radii values are shown in table 9 2 A small amount of flattening in bends is acceptable but do not exceed 5 percent of the original outside diameter Excessive flattening will cause fatigue failure of the tube When installing the replacement tubing line it up correctly with the mating part so that it is not forced into alignment by tightening of the coupling nuts Tube Connections Many tube connections are made using flared tube ends with Par 9 29 Page 9 428 AC 43 13 1B standard connection fittings AN 818 MS 20818 nut and AN 819 MS 20819 sleeve In forming flares cut the tube ends square file smooth remove all burrs and sharp edges and thoroughly clean The tubing is then flared using the correct 37 degree avia
172. ge 11 515 9 8 98 AC 43 13 1B STEP 4 Refer to the altitude derating curve of figure 11 6 look for sea level and 20 000 feet on the abscissa since these are the conditions at which the load will be carried The wire must be derated by a factor of 1 0 and 0 91 respectively STEP 5 Derate the size 12 in a bundle ratings by multiplying 29 2 amps at sea level and 26 6 amps at 20 000 feet by 1 0 and 0 91 respectively to obtained 29 2 amps and 23 8 amps The total bundle capacity at sea level and 25 C ambient is 29 2x12 350 4 amps At 20 000 feet and 60 C ambient the bundle capacity is 23 8x12 285 6 amps Each size 12 wire can carry 29 2 amps at sea level 25 C ambient or 23 8 amps at 20 000 feet 60 C ambient STEP 6 Determine the actual circuit current for each wire in the bundle and for the bundle If the values calculated in Step 5 are exceeded select the next larger size wire and repeat the calculations 11 70 11 75 RESERVED Par 11 76 Page 11 516 Par 11 76 9 8 98 AC 43 13 1B SECTION 6 AIRCRAFT ELECTRICAL WIRE SELECTION GENERAL Aircraft service imposes severe environmental condition on electrical wire To ensure satisfactory service inspect wire annually for abrasions defective insulation condition of terminations and potential corrosion Grounding connections for power distribution equipment and electromagnetic shielding must be given particular attention to ensure that electrical bonding re
173. ges for damage due to excessive heat especially if brake drag Par 9 11 Page 9 419 AC 43 13 1 or severe braking has been reported during taxi takeoff or landing Tire Clearance Look for marks on tires the gear and in the wheel wells that might indicate rubbing due to inadequate clearance Surface Condition The surface condition of a tire can be inspected with the tire on the aircraft The tread should be checked for abnormal wear If the tread is worn in the center of the tire but not on the edges this indicates that the tire is over inflated and the operational air pressure should be reduced On the other hand a tire worn on the edges but not in the center indicates under inflation These indications are shown in figure 9 7 INFLATION OF TIRES It is recommended that no person should stand directly in front of the wheel while it is being inflated and that the tire not be inflated beyond recommended pressure when it is not being installed in a safety cage Over inflation can cause damage to the aircraft as well as personal injury Under inflation will cause excessive tire wear and imbalance NOTE The use of nitrogen to inflate tires is recommended Do not use oxygen to inflate tires Deflate tires 9 8 98 NORMAL wear OVER INFLATION UNDER INFLATION FIGURE 9 7 Examples of tread wear indicating over inflation and under inflation prior to removing them from the aircraft or when bu
174. h repair allowable Aw Aw Aw x w x 0 01 2 5 x 1 88 x 0 01 0 05 in Par 8 Page 398 Step 5 Calculate the minimum blade width limit w1 at the repair location W w Aw 1 88 0 05 1 83 in Example 2 Determine the blade thickness repair allowable At and minimum blade thickness limit for a blade having a diameter d of 10 ft 6 in The repair location 9 8 98 AC 43 13 1B r is 43 in from the shank and the original as manufactured blade thickness f at the repair location is 0 07 in Step 1 Calculate the blade radius r r 4 2 10 ft 6 in 2 126 2 63 in Step 2 Calculate percent of blade radius to repair r96 r r r x 100 43 63 x 100 68 Step 3 Determine percent reduction in thickness A196 from figure 8 28 Step 4 Calculate the blade thickness repair allowable Ar At At x t 0 01 4 0 x 0 07 x 0 01 0 003 in Step 5 Calculate the minimum blade thickness limit t at the repair location fj t At 0 07 0 003 0 067 in STEEL HUBS AND HUB PARTS Repairs to steel hubs and parts must be accomplished only in accordance with the manufacturer s recommendations Welding and remachining is permissible only when covered by manufacturer s service bulletins SB PROPELLER HUB AND FLANGE REPAIR When the fixed pitch propeller bolt holes in a hub or crankshaft become damaged or oversized it is permissible to make repairs by using me
175. he pump supplying the system System pressure should be observed during operation of each subsystem to ensure that the engine driven pump maintains the required pressure Troubleshooting Hydraulic system troubleshooting varies according to the complexity of the system and the components in the system It is therefore important that the 9 8 98 technician refer to the troubleshooting information furnished by the manufacturer Lack of pressure in a system can be caused by a sheared pump shaft defective relief valve the pressure regulator an unloading valve stuck in the kicked out position lack of fluid in the system the check valve installed backward or any condition that permits free flow back to the reservoir or overboard lf a system operates satisfactorily with a ground test unit but not with the system pump the pump should be examined If a system fails to hold pressure in the pressure section the likely cause is the pressure regulator an unloading valve a leaking relief valve or a leaking check valve If the pump fails to keep pressure up during operation of the subsystem the pump may be worn or one of the pressure control units may be leaking High pressure in a system may be caused by a defective or improperly adjusted pressure regulator an unloading valve or by an obstruction in a line or control unit Unusual noise in a hydraulic system such as banging and chattering may be caused by air or co
176. he wiring in the area surrounding the sampling area is a candidate for replacement TERMINALS AND TERMINAL BLOCKS Inspect to ensure that the following installation requirements are met Par 11 96 AC 43 13 1B Insulating tubing is placed over terminals except pre insulated types to provide electrical protection and mechanical support and is secured to prevent slippage of the tubing from the terminal Terminal module blocks are securely mounted and provided with adequate electrical clearances or insulation strips between mounting hardware and conductive parts except when the terminal block is used for grounding purposes Terminal connections to terminal module block studs and nuts on unused studs are tight Evidence of overheating and corrosion is not present on connections to terminal module block studs Physical damage to studs stud threads and terminal module blocks is not evident Replace cracked terminal strips and those studs with stripped threads The number of terminal connections to a terminal block stud does not exceed four unless specifically authorized Shielding should be dead ended with suitable insulated terminals All wires terminal blocks and individual studs are clearly identified to correspond to aircraft wiring manuals Terminations should be made using terminals of the proper size and the appropriate terminal crimping tools FUSES AND FUSE HOLDERS Inspect as follows Check security o
177. hecking the fluid level of an air oil strut is given in the manufacturer s maintenance manual An alternate means of servicing an oil strut is to jack up the aircraft remove the strut s valve cap release the air charge in the strut by depressing the valve core remove the strut s valve core attach a clean two foot rubber or plastic hose to the threaded portion that houses the valve core and secure with a hose clamp Put the other end of the hose into a clean two quart container filled with the correct hydraulic fluid for the strut Cover the container with a clean rag to prevent spillage Now slowly raise the gear strut assembly either manually or with another jack under the strut This will drive the remaining air out of the strut into the container of hydraulic fluid Once the gear is fully retracted slowly lower the gear The hydraulic fluid in the can will be sucked into the strut Repeat this procedure until you cannot hear any more air bubbles in the container when the wheel strut is fully retracted With the strut fully retracted remove the hose insert the valve core lower the gear and service the strut with nitrogen to get the proper strut extension The entire structure of the landing gear should be closely examined for cracks nicks cuts corrosion damage or any other condition that can cause stress concentrations and eventual failure The exposed lower end of the air oleo piston is especially susceptible to damage and corros
178. hould be sufficient to provide about 5 to 8 percent slack Avoid tight bends in flex lines as they may result in Par 9 30 Page 9 429 AC 43 13 1B Minimum bend radii Aluminum alloy tubing measured to tubing Flare MS33583 for use centerline Dimension on oxygen lines only in inches Minimum Maximum Alum Steel Alloy failure Never exceed the minimum bend radii as indicated in figure 9 10 Teflon hose is used in many aircraft systems because it has superior qualities for certain applications Teflon is compounded from tetrafluoroethylene resin which is unaffected by fluids normally used in aircraft It has an operating range of 65 to 450 F For these reasons Teflon is used in hydraulic and engine lubricating systems where temperatures and pressures preclude the use of rubber hose Although Teflon hose has excellent performance qualities it also has peculiar characteristics that require extra care in handling It tends to assume a permanent set when exposed to high pressure or temperature Do not attempt to straighten a hose that has been in service Any excessive bending or twisting may cause kinking or weakening of the tubing wall Replace any hose that shows signs of leakage abrasion or kinking Any hose suspected of kinking may be checked with a steel ball of proper size Table 9 4 shows hose and ball sizes The ball will not pass through if the hose is distorted beyond limits If the hose fittings are of the re
179. iation have been listed in general Refer to ANSI maintenance technician They are in Y32 2 1975 for more specific detail on each accordance with ANSI Y32 2 1975 symbol TABLE 11 27 Electronic Electrical Symbols Adjustability Variability Radiation Indicators Physical State Recognition Test Point Recognition Polarity Markings Direction of Flow of Power Signal or Information Kind of Current Envelope Enclosure Shield Shielding Special Connector or Cable Indicator Par 11 271 Page 11 586 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued lt gt m 3m Battery v i Thermal Element Thermomechanical Transducer Thermocouple Spark Gap Ignitor Gap Continuous Loop Fire Detector Temperature Sensor Ignitor Plug Par 11 271 Page 11 587 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Transmission Patch Conductor Cable Wiring Distribution Lines Transmission Lines Alternative or Conditioned Wiring Associated or Future Par 11 272 Page 11 588 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Intentional Isolation of Direct Current Path in Coaxial or Waveguide Applications Circuit Return Pressure Tight Bulkhead Cable Gland Cable Sealing End Switching Function Electrical Contact Par 11 272 Page 11 589 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrica
180. ic changes while in flight CLEANING In order to ensure proper ground connection conductivity all paint primer anodize coating grease and other foreign material must be carefully removed from areas that conduct electricity On aluminum surfaces apply chemical surface treatment to the cleaned bare metal surface in accordance with the manufacturer s instructions within 4 8 hours depending on ambient moisture contaminate content HARDWARE ASSEMBLY Details of bonding connections must be described in maintenance manuals and adhered to carefully when connections are removed or replaced during maintenance operations In order to avoid corrosion problems and ensure long term integrity of the electrical connection hardware used for this purpose must be as defined in these documents or at least be equivalent in material and surface Installation of fasteners used in bonded or grounded connections should be made in accordance with SAE ARP 1870 Threaded fasteners must be torqued to the level required by SAE ARP 1928 11 198 11 204 RESERVED Page 11 561 and 11 82 Par 11 205 9 8 98 AC 43 13 1B SECTION 16 WIRE MARKING GENERAL The proper identification of electrical wires and cables with their circuits and voltages is necessary to provide safety of operation safety to maintenance personnel and ease of maintenance Each wire and cable should be marked with a part number It is common practice for wire ma
181. ical energy global positioning system GPS a navigation system that employs satellite transmitted signals to determine the aircraft s location grain the direction size arrangement appearance or quality of the fibers in wood or metal grain diagonal annual rings in wood at an angle with the axis of a piece as a result of sawing at an angle with the bark of the tree grommet an insulating washer that protects the sides of holes through which wires must pass or a metal or plastic drain attached to fabric on aircraft gross weight the total weight of the aircraft including its contents grounding the term is usually applied to a particular form of bonding that is the process of electrically connecting conductive objects to either conductive structure or some other conductive return path for the purpose of safely completing either a normal or fault circuit harness a cable harness is a group of cables or wires securely tied as a unit honeycomb manufactured product consisting of a resin impregnated sheet or metal material which has been corrugated or expanded into hexagon shaped and other structural shaped cells Primarily used as core material for sandwich constructions inductance L the ability of a coil or conductor to oppose a change in current flow insulator a material that will not conduct current to an appreciable degree 621 9 8 98 integrated circuit small complete circuit bui
182. ical stresses the probability of degradation or catastrophic failure is lessened direct current electrode negative the arrangement of direct current arc welding leads in which the work is the positive pole and the electrode is the negative pole of the welding arc direct current electrode positive the arrangement of direct current arc welding leads in which the work is the negative pole and the electrode is the positive pole of the welding arc discontinuity an interruption in the normal physical structure or configuration of a part such as acrack lap seam inclusion or porosity distal tip the tip lens end of a borescope dope liquid applied to fabric to tauten it by shrinking strengthen it and render it airtight by acting as a filler dopeproofing protecting a surface from the chemicals and chafing qualities of dope and doped fabrics drape the ability of tape and broad goods to conform to a contoured shape drip loop a bundle installation method used to prevent water or other fluid contaminants from running down the wiring into a connector dry rot a term loosely applied to many types of wood decay but especially to that which when in an advanced stage permits the wood to be easily crushed to a dry powder The term is actually a misnomer for any decay since all fungi require considerable moisture for growth 619 9 8 98 dwell time the total time that a penetrant emulsifier or rem
183. ich are covered by the recommendations should be made and only manufacturer s recommendations should be those replacement parts which are approved made and only those replacement parts which under 14 CFR part 21 should be used Par 8 74 Page 8 400 9 8 98 AC 43 13 1B WOOD HUB OF PROPELLER WOOD HUB OF PROPELLER b 1 D 1 4 LARGER THAN BOLT SIZE METHOD A METHOD B REPAIR OF DAMAGED OR ELONGATED BOLT HOLES REPAIR OF ELONGATED BOLT HOLES IN PROPELLER HUB FLANGES IN PROPELLER 1 DRILLED BOLT WITH CASTELATED NUT OR UNDRILLED BOLT WITH SELF LOCKING NUT 2 BOLT WITH HEAD DRILLED FOR SAFETY WIRING NOTE THESE REPAIRS ARE PERMITTED ONLY ON THE DRIVING FLANGE OF THE PROPELLER HUB AND THE ADJACENT FACE OF THE PROPELLER FIGURE 8 29 Repair of fixed pitch hub and propeller with elongated or damaged bolt holes 8 79 8 90 RESERVED Par 8 78 Page 8 401 and 8 36 9 8 98 AC 43 13 1B SECTION 5 INSPECTION OF PROPELLERS GENERAL All propellers regardless of the material from which they are made should be regularly and carefully inspected for any possible defect Any doubtful condition such as looseness of parts nicks cracks scratches bruises or loss of finish should be carefully investigated and the condition checked against repair and maintenance specifications for that particular type of propeller Any propeller that has struck a foreign object during service should be prompily inspected for po
184. icro Switches Inspect micro switches for security of attachment cleanliness general condition and proper operation Check the associated wiring for chafing proper routing and to determine that protective covers are installed on wiring terminals if required Check the condition of the rubber dust boots which protect the micro switch plungers from dirt and corrosion TIRE AND TUBE MAINTENANCE A program of tire maintenance can minimize tire failures and increase tire service life Correct balance is important as a heavy spot on an aircraft tire tube or wheel assembly causes that heavy spot to always hit the ground first upon landing This results in excessive wear at one spot and an early failure at that part of the tire A severe case of imbalance causes excessive vibration during take off and landing especially at high speed A protective cover should be placed over a tire while servicing units that might drip fluid on the tire FLOATS AND SKIS Aircraft operated from water may be provided with either a single float or a double float depending upon the design and construction however if an aircraft is an amphibian it has a hull for flotation and then may need only wingtip floats Amphibious aircraft have floats or a hull for operating on water and retractable wheels for land operation Skis are used for operating on snow and ice The skis may be made of wood metal or composite materials There are three basic styles of s
185. ified approximately at the center Added identification marker sleeves should be so located that ties clamps or supporting devices need not be removed in order to read the identification The wire identification code must be printed to read horizontally from left to right or vertically from top to bottom The two methods of marking wire or cable are as follows Direct marking is accomplished by printing the cable s outer covering See figure 11 23 Indirect marking is accomplished by printing a heat shrinkable sleeve and installing the printed sleeve on the wire or cables outer covering Indirect marked wire or cable should be identified with printed sleeves at each end and at intervals not longer than 6feet The individual wires inside a cable should be identified within 3 inches of their termination See figure 11 24 TYPES OF WIRE MARKINGS The preferred method is to mark directly on the wire Teflon coated wires shielded wiring multiconductor cable and thermocouple wires usually require special sleeves to carry identification marks Whatever method of marking is used the marking should be legible and the color should contrast with the wire insulation or sleeve Extreme care must therefore be taken during circuit identification by a hot stamp machine on insulation wall 10 mils or thinner 9 8 98 AC 43 13 1B H215A20 b Single wire without sleeve INCH WHITE BLUE Seno ORANGE Y nds H
186. ighing D The horizontal distance measured from the datum to the main wheel weighing point L The horizontal distance measured from the main wheel weighing point to the nose or tail weighing point F The weight at the nose weighing point R The weight at the tail weighing point FIGURE 10 4 Empty weight center of gravity formulas Par 10 2 Page 10 462 9 8 98 AC 43 13 1B DATUM LEADING EDGE OF WING ROOT SECTION TARE 27 LBS SCALE READING D MEASURED F WEIGHING POINT L MEASURED TAIL WHEEL TO FIND EMPTY WEIGHT AND EMPTY WEIGHT CENTER OF GRAVITY Datum is the leading edge of the wing from aircraft specification D Actual measured horizontal distance from the main wheel weighing point main wheel to the Datum L Actual measured horizontal distance from the rear wheel weighing point rear wheel to the main wheel weighing point Weighing SOLVING EMPTY WEIGHT Lii M re Ml Tof e SOLVING EMPTY WEIGHT CENTER OF GRAVITY Rx xL 40 x 222 Formula C G D w 3 169 3 7 6 10 6 Reference for formula Figure 10 4 This case is shown properly entered on a sample weight and balance report form Figure 10 17 FIGURE 10 5 Empty weight and empty center of gravity tail wheel type aircraft Par 10 2 Page 10 463 9 8 98 AC 43 13 1B DATUM LEADING EDGE OF en WING ROOT SECTION LEFT SCALE 620 LBS TARE 5LBS RIGHT SC
187. igure 11 2 and 11 3 Example No 2 Find the wire size required to meet the allowable voltage drop in table 11 6 for a wire carrying current at an elevated conductor temperature using the following information The wire run is 15 feet long including the ground wire Circuit current is 20 amps continuous The voltage source is 28 volts The wire type used has a 200 C conductor rating and it is intended to use this thermal rating to minimize the wire gauge Assume that the method described in paragraph 11 66d 6 was used and the minimum wire size to carry the required current is 14 Par 11 68 AC 43 13 1B Ambient temperature is 50 C under hottest operating conditions STEP 1 Assuming that the recommended load bank testing described in paragraph 11 66d 5 is unable to be conducted then the estimated calculation methods outlined in paragraph 11 66d 6 may be used to determine the estimated maximum current Imax The 14 gauge wire mentioned above can carry the required current at 50 C ambient allowing for altitude and bundle derating Use figure 11 4a to calculate the Imax a 14 gauge wire can carry Find the temperature differences Tr Ta 200 C 50 150 C Follow the 150 C line to intersect with 14 wire size and reads 47 Amps at bottom of chart current amperes Use figure 11 6 left side of chart reads 0 91 for 20 000 feet multiple 0 91 x 47 Amps 42 77 Amps Use figure 11 5 f
188. ilt up tire assemblies are being shipped The airframe manufacturer s load and pressure chart should be consulted before inflating tires Sufficiently inflate the tires to seat the tire beads then deflate them to allow the tube to assume its position Inflate to the recommended pressure with the tire in a horizontal position WHEEL INSPECTION Check wheels for damage Wheels that are cracked or damaged must be taken out of service for repair or replacement in accordance with the manufacturer s instruction manual WHEEL INSTALLATION There are various procedures used for the installation of wheel assemblies on an aircraft The axle should first be cleaned and inspected for surface damage damage to the axle threads and the general condition and security of bolts holding the axle onto the landing gear leg The wheel bearings should be cleaned and Par 9 15 Page 9 420 AC 43 13 1B packed with approved grease The wheel bearing and tire must be inspected and assembled Many aircraft have specific torque requirements for the wheel retaining nuts These torque requirements may have two values specified The retaining nut is first tightened to the higher value to seat the bearing then is backed off and tightened to the lower value specified While tightening the wheel retaining nuts the wheel should be rotated Great care should be exercised to see that the wheel retaining nuts are not over tightened In the absence of specifi
189. ind the derate factor for 8 wires in a bundle at 60 percent First find the number of wires in the bundle 8 at bottom of graph and intersect with the 60 percent curve meet Read derating factor left side of graph which is 0 6 Multiply 0 6 x 42 77 Amps 26 Amps T estimated conductor temperature T 50 C ambient temperature 200 C maximum conductor rated temperature I 20 amps circuit current continuous Page 11 509 9 8 98 AC 43 13 1B M rian i T Y ELE L4 TIN C PANNI MEP aaa an eee cdi cbr ur TEMPERATURE DIFFERENCE 2 a lt x gt s 7 8 9 10 30 40 50 CURRENT AMPERES A NOT TO BE USED AS SINGLE WIRE FIGURE 11 4a Single copper wire in free air Imax 26 amps this is the maximum current the 14 gauge wire could carry at 50 C ambient L 15 5 feet maximum run length for size 14 wire carrying 20 amps from figure 11 2 STEP 2 From paragraph 11 66d 5 and 6 determine the and the resultant maximum wire length when the increased resistance of the higher temperature conductor is taken into account Par 11 68 T T T T Vl 1 1 T 50 200 C 50 C 420A 26A 50 C 150 C 877 5 182 C Q54 5 CY L 234 5 254 5 C 15 5Ft 234 5 C 182 C L 9 5 ft Page 11 510 9
190. ing is never allowed to exceed the red line except for short intermittent loads the generator or alternator will not be overloaded Par 11 37 AC 43 13 1B Where the use of placards or monitoring devices is not practical or desired and where assurance is needed that the battery will be charged in flight the total continuous connected electrical load should be held to approximately 80 percent of the total generator output capacity When more than one generator is used in parallel the total rated output is the combined output of the installed generators When two or more generators and alternators are operated in parallel and the total connected system load can exceed the rated output of a single generator a method should be provided for quickly coping with a sudden overload that can be caused by generator or engine failure A quick load reduction system or procedure should be identified whereby the total load can be reduced by the pilot to a quantity which is within the rated capacity of the remaining operable generator or generators DETERMINATION OF ELECTRICAL LOAD The connected load of an aircraft s electrical system may be determined by any one ora combination of several acceptable methods techniques or practices However those with a need to know the status of a particular aircraft s electrical system should have available accurate and up to date data concerning the capacity of the installed electrical power source s
191. ion showing that the c g of the aircraft usually in the fully loaded condition falls between the extreme conditions Forward Weight and Balance Check When a forward weight and balance check is made establish that neither the maximum weight nor the forward c g limit listed in the TCDS and Aircraft Specifications are exceeded To make this check the following information is needed The weights arms and moment of the empty aircraft The maximum weights arms and moments of the items of useful load that are located ahead of the forward c g limit The minimum weights arms and moments of the items of useful load that are located aft of the forward c g limit A typical example of the computation necessary to make this check using this data is shown in figure 10 10 Rearward Weight and Balance Check When a rearward weight and balance check is made establish that neither the maximum weight nor the rearward c g limit listed in the TCDS and Aircraft Specifications are exceeded To make this check the following information is needed The weight arms and moments of the empty aircraft The maximum weights arms and moments of the items of useful load that are located aft of the rearward c g limit 9 8 98 AC 43 13 1B I DATUM choo NO BAGGAGE NO PASSENGERS FULL OIL MINIMUM FUEL PILOT ONLY FORWARD LIMIT TO CHECK MOST FORWARD WEIGHT AND BALANCE EXTREME GIVEN Actual empty weight of the air
192. ion unless climate storage or operational conditions indicate the need for more frequent inspections Ref TSO C13 LIFE PRESERVER INSPECTION Life preservers should be inspected at 12 month intervals for cuts tears or other damage to the rubberized material Check the mouth valves and tubing for leakage corrosion and deterioration Remove the cylinder and check the discharge mechanism by operating the lever to ascertain that the pin operates freely Check the gaskets and valve cores of the cylinder container and the pull cord for deterioration If no defects are found inflate the preserver with air to a 2 psi pressure and allow to stand for 12 hours If the preserver still has adequate rigidity at the end of that time deflate and fit with CO cylinders having weights not less than that indicated on them by the manufacturer All cylinders made in accordance with joint Army Navy Specification MIL C 00601D are so stamped and have a minimum permissible weight stamped on them The use of such CO cylinders is recommended Having fitted the preserver with an adequately charged cylinder mark the preserver to indicate the date of inspection and patch it to the container It is recommended that the aforementioned procedure be repeated every 12 month period utilizing the CO cartridge for inflation Carbon dioxide permeates the rubberized fabric at a faster rate than air and will indicate if the porosity of the material is excessi
193. ion which can lead to seal damage because the strut is compressed 9 8 98 and the piston moves past the strut lower seal causing the seal to leak fluid and air Small nicks or cuts can be filed and burnished to a smooth contour eliminating the point of stress concentration If a crack is found in a landing gear member the part must be replaced All bolts and fittings should be checked for security and condition Bolts in the torque links and shimmy damper tend to wear and become loose due to the operational loads placed on them The nose wheel shimmy damper should be checked for proper operation and any evidence of leaking All required servicing should be performed in accordance with the aircraft service manual INSPECTION OF RETRACTABLE LANDING GEAR Inspection of the retractable landing gear should include all applicable items mentioned in the inspection for the fixed gear In addition the actuating mechanisms must be inspected for wear looseness in any joint trunnion or bearing leakage of fluid from any hydraulic line or unit and smoothness of operation The operational check is performed by jacking the aircraft according to the manufacturer s instructions and then operating the gear retracting and extending system During the operational test the smoothness of operation effectiveness of up and down locks operation of the warning horn operation of indicating systems clearance of tires in wheel wells and operation
194. ion system electric motors and hydraulic pumps This condition can lead to component malfunctions therefore it is recommended that cleanliness be stressed during and after lubrication FIXED GEAR INSPECTION Fixed landing gear should be examined regularly for wear deterioration corrosion alignment and other factors that may cause failure or unsatisfactory operation During a 100 hour or annual inspection of the fixed gear the aircraft should be jacked up to relieve the aircraft weight The gear struts and wheels should be checked for abnormal play and corrected Old aircraft landing gear that employs a rubber shock bungee cord for shock absorption must be inspected for age fraying of the braided sheath narrowing necking of the cord and wear at points of contact with the structure and stretch If the age of the shock cord is near 5 years or more it is advisable to replace it with a new cord A cord that shows other defects should be replaced regardless of age 9 8 98 The cord is color coded to indicate when it was manufactured and to determine the life of the shock cord According to MIL C 5651A the color code for the year of manufacture is repeated in cycles of 5 years Table 9 1 shows the color of the code thread for each year and quarter year TABLE 9 1 Bungee cord color codes YEARS ENDING COLOR QUARTER COLOR WITH Oor5 Black lst Red lor6 Green 2nd Blue 20r7 Red 3rd Green 3or8 Blue Ath Yellow 4 or 9 Yellow
195. istance of each connection does not exceed 003 ohm The jumper should not interfere with the operation of movable aircraft elements such as surface controls nor should normal movement of these elements result in damage to the bonding jumper Bonding Connections To ensure a low resistance connection nonconducting finishes such as paint and anodizing films should be removed from the attachment surface to be contacted by the bonding terminal On aluminum surfaces a suitable conductive chemical surface treatment such as Alodine should be applied to the surfaces within 24 hours of the removal of the original finish Refer to SAE ARP 1870 for detailed instructions Electric wiring should not be grounded directly to magnesium parts Corrosion Protection One of the more frequent causes of failures in electrical system bonding and grounding is corrosion Aircraft operating near salt water are particularly vulnerable to this failure mode Because bonding and grounding connections may involve a variety of materials and finishes it is important to protect completely against dissimilar metal corrosion areas around completed connections should be post finished in accordance with the original finish requirements or with some other suitable protective finish within 24 hours of the cleaning process In applications exposed to salt spray environment a suitable noncorrosive sealant such as one conforming to MIL S 8802 should be used to se
196. it are shown in table 11 24 TABLE 11 24 Minimum bending radii for flexible aluminum or brass conduit Nominal 1 0 of conduit inches Minimum bending radius inside inches 11 254 11 259 RESERVED 9 8 98 AC 43 13 1B SECTION 19 PROTECTION OF UNUSED CONNECTORS GENERAL Connectors may have one or more contact cavities that are not used Depending on the connector installation unused connector contact cavities may need to be properly sealed to avoid damage to the connector or have string wire installed QUICK REFERENCE CHART A quick reference chart of unused connector contact cavity requirements is given in table 11 25 These requirements apply to harness manufacturing or connector replacement only UNPRESSURIZED AREA CONNECTORS Connectors may be installed in unpressurized areas of the aircraft Unused connector contact cavities installed in unpressurized areas should be properly sealed as follows Firewall Connectors Installations Firewall unused connector contact cavities should be filled with spare contacts and stub wires See figure 11 39 Construct stub wires using high temperature wire 260 C Ensure that stub wires are of the same type of wires in the bundle Crimp the proper contact for the connector and cavity being used onto the wire Install the crimped contact into the unused cavity Extend stub wires beyond the back of the connector clamp from 1 5 to 6 inches Feather trim stu
197. itable drain holes should be provided at the low points Bonding clamps do not cause damage to the conduit Weatherproof shields on flexible conduits of the nose and main landing gear and in wheel wells are not broken that metallic braid of weatherproof conduit is not exposed and that conduit nuts ferrules and conduit fittings are installed securely Ends of open conduits are flared or routed to avoid sharp edges that could chafe wires exiting from the conduit JUNCTIONS Ensure that only aircraft manufacturer approved devices such as solderless type terminals terminal blocks connectors disconnect splices permanent splices and feed through bushings are used for cable junctions Inspect for the provisions outlined below Electrical junctions should be protected from short circuits resulting from movement of personnel cargo cases and other loose or stored materials Protection should be provided by covering the junction installing them in junction boxes or by locating them in such a manner that additional protection is not required etc Exposed junctions and buses should be protected with insulating materials Junctions and buses located within enclosed areas containing only electrical and electronic equipment are not considered as exposed Electrical junctions should be mechanically and electrically secure They should not be subject to mechanical strain or used as a support for insulating materials except for insul
198. ith subsequent heat curing The successive layers rarely reach a total buildup of 1 mil polymerization basic processes for making large high polymer molecules from small ones normally without chemical change can be by addition condensation rearrangement or other methods porosity cavity type discontinuities in metal formed by gas entrapment during solidification prepreg a mat a fabric or covering impregnated with resin that is ready for lay up and curing propeller is a rotating airfoil that consists of two or more blades attached to a central hub which is mounted on the engine crankshaft protractor is a device for measuring angles PTFE Tape Insulation polytetrafluoroethylene tape commonly known by the trade name TEFLON wrapped around a conductor and then centered with heat fusing the layers into a virtually homogeneous mass It is used both as a primary insulation against the conductor and as an outer layer or jacket over a shield Maximum temperature rating is 260 C PVF Polyvinylidine Fluoride a fluorocarbon plastic that when used in aircraft wire is invariably radiation cross linked and employed as the outer layer radar radio detecting and ranging radio equipment that utilizes reflected pulse signals to locate and determine the distance to any reflecting object within its range radome a nonmetallic cover used to protect the antenna assembly of a radar system reinforcing ta
199. kis A conventional ski shown in figure 9 1 replaces the wheel on the axle The shock cord is used to hold the toe of the ski up 9 8 98 AC 43 13 1B when landing The safety cable check cable prevent the ski from pivoting through too great an angle during flight The wheel ski is designed to mount on the aircraft along with the tire The ski has a portion cut out that allows the tire to extend slightly below the ski so that the aircraft can be operated from conventional runways with the wheels or from snow or ice surfaces using the ski This arrangement has a small wheel mounted on the heel of the ski so that it does not drag on conventional runways In retractable wheel ski arrangements the ski is mounted on a common axle with the wheel In this arrangement the ski can be extended below the level of the wheel for landing on snow or ice The ski can be retracted above the bottom of the wheel for operations from conventional runways hydraulic system is commonly used for the retraction system operation Fitting 6 Fabric removed to facilitate inspection 2 Shock Cord 7 Check Cable 3 Safety Cable 8 Clevis 4 Tape 9 Ski Pedestal 5 Crust cutter Cable 10 Pedestal Height FIGURE 9 1 A typical ski installation Par 9 7 Page 9 415 9 8 98 INSPECTION AND REPAIR OF FLOATS AND SKIS Inspection of floats and skis involves examination for damage due to corrosion collision with other objects hard landings and
200. l Symbols continued Basic Contact Assemblies Magnetic Blowout Coil Operating Coil Relay Coil Switch Pushbutton Momentary or Spring Return Par 11 272 Page 11 590 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Two Circuit Maintained or Not Spring Return Nonlocking Switching Momentary or Spring Return Locking Switch Combination Locking and Nonlocking Switch Key Type Switch Lever Switch Par 11 272 Page 11 591 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Selector or Multiposition Switch Safety Interlock Limit Switch Sensitive Switch Switches with Time Delay Feature Flow Actuated Switch Par 11 272 Page 11 592 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Liquid Level Actuated Switch Pressure or Vacuum Actuated Switch Temperature Actuated Switch Thermostat Flasher Self Interrupting Switch Foot Operated Switch Foot Switch Switch Operated by Shaft Rotation and Responsive to Speed or Direction Switches with Specific Features Par 11 272 Page 11 593 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Governor Speed Regulator Terminals Par 11 272 Page 11 594 9 8 98 AC 43 13 1B TABLE 11 27 Electronic Electrical Symbols continued Cable Termination Connector Disconnecting Device Connectors of the Type Commonly Used for
201. landing gear support trusses for cracked welds sheared bolts and rivets and buckled structures wheels and tires for cracks and cuts and upper and lower wing surfaces for wrinkles deformation and loose or sheared rivets If any damage is found a detailed inspection is recommended RETRACTION TESTS Periodically perform a complete operational check of the landing gear retraction system Inspect the normal extension and retraction system the emergency extension system and the indicating and emergency warning system Determine that the actuating cylinders linkage slide tubes sprockets chain or drive gears gear doors and the up and down locks are in good condition and properly adjusted and lubricated and the wheels have adequate clearance in the wheel wells In addition an electrical continuity check of micro switches and associated wiring is recommended Only qualified personnel should attempt adjustments to the gear position and warning system micro switches Then closely follow the manufacturer s recommendations TIRE INSPECTION AND REPAIR Tires should be inspected frequently for cuts worn spots bulges on the side walls foreign bodies in the treads and tread condition 9 8 98 Defective or worn tires may be repaired or retreaded The term retread refers to several means of restoring a used tire whether by applying a new tread alone or tread and side wall material in varying amounts The following guidelines sh
202. ld result in interference with movable controls wire bundle contact with movable equipment or chafing damage to essential or unprotected wiring They must not be used on vertical runs where inadvertent slack migration could result in chafing or other damage Clamps must be installed with their attachment hardware positioned above them wherever practicable so that they are unlikely to rotate Page 11 538 as the result of wire bundle weight or wire bundle chafing See figure 11 11 Clamps lined with nonmetallic material should be used to support the wire bundle along the run Tying may be used between clamps but should not be considered as a substitute for adequate clamping Adhesive tapes are subject to age deterioration and therefore are not acceptable as a clamping means The back of the clamp whenever practical should be rested against a structural member Clamps must be installed in such a manner that the electrical wires do not come in contact with other parts of the aircraft when subjected to vibration Sufficient slack should be left between the last clamp and the electrical equipment to prevent strain at the terminal and to minimize adverse effects on shock mounted equipment Where wires or wire bundles pass through bulkheads or other structural members a grommet or suitable clamp should be provided to prevent abrasion When wire bundle is clamped into position if there is less than 3 8 inch clearance between the bulkh
203. le to both portable and permanently installed equipment Aircraft Gaseous Oxygen Systems The oxygen in gaseous systems is supplied from one or more high or low pressure oxygen cylinders Since the oxygen is compressed within the cylinder the amount of pressure indicated on the system gauge bears a direct relationship to the amount of oxygen contained in the cylinder The pressure indicating line connection is normally located between the cylinder and a pressure reducing valve Par 9 46 Page 9 448 AC 43 13 1B NOTE Some of the gaseous oxygen systems do not use pressure reducing valves The high pressure is reduced to a useable pressure by a regulator This regulator is located between the high and low pressure system CAUTION Oxygen rich environments are dangerous Portable Oxygen Systems The three basic types of portable oxygen systems are demand pressure demand and continuous flow The components of these systems are identical to those of a permanent installation with the exception that some parts are miniaturized as necessary This is done in order that they may be contained in a case or strapped around a person s shoulder It is for this portability reason that special attention be given to assuring that any storage or security provision for portable oxygen equipment in the aircraft is adequate in good condition and accessible to the user NOTE Check portable equipment including its security provisions frequen
204. lectromotive force EMF difference electrical potential measured in volts electron a negative charge that revolves around the nucleus of an atom a unit of a negative electrical charge electronics general term that describes the branch of electrical science and technology that treats the behavior and effects of electron emission and transmission electron Volt eV a unit of energy equal to the energy aquired by an electron falling though AC 43 13 1B Appendix 1 potential differences of one volt aproximately 1 602X 10 19 joule emulsion type cleaner a chemical cleaner which mixes with water or petroleum solvent to form an emulsion a mixture which will separate if allowed to stand It is used to loosen dirt soot or oxide films from the surface of an aircraft epoxy one of various usually thermosetting resins capable of forming tight cross linked polymer structures marked by toughness strong adhesion high corrosion and chemical resistance used especially in adhesives and surface coating epoxy primer a two part catalyzed material used to provide a good bond between a surface and a surface coating epoxy resin a common thermosetting resin which exhibits exceptionally good adhesion low cure shrinkage and low water absorption properties erosion loss of metal from metal surfaces by the action of small particles such as sand or water ETFE Frequently referred to by the trade name TEFZEL
205. led Use a sealed switch when the switch will be exposed to a dirty environment during storage assembly or operation Use a higher level of sealing when the switch will not have an arcing load to self clean the contacts Low energy loads tend to be more susceptible to contamination Proximity switches for aircraft applications typically have a metal face and potting material surrounding any electronics and lead wire exits The potting material should be compatible with the fluids the switch will be exposed to in the environment The plastic sensing face of some proximity switches may be subject to absorption of water that may cause the operating point to shift should be protected Switch Installation Hazardous errors in switch operation may be avoided by logical and consistent installation On off two position switches should be mounted so that the position is reached by an upward or forward movement of the toggle When the switch controls movable aircraft elements such as landing gear or flaps the toggle should move in the same direction as the desired motion Inadvertent operation of switches can be prevented by mounting suitable guards over the switches RELAYS A relay is an electrically controlled device that opens and closes electrical contacts to effect the operation of other devices in the same or in another electrical circuit The relay converts electrical energy into mechanical energy through various m
206. lizing the battery should be washed with clean water and thoroughly dried ADJUSTMENT AND REPAIR Accomplish adjustments to items of equipment such as regulators alternators generators contactors control devices inverters and relays at a location outside the aircraft and on a test stand or test bench where all necessary instruments and test equipment are at hand Follow the adjustment and repair procedures outlined by the equipment or aircraft manufacturer Replacement or repair must be accomplished as a part of routine maintenance Adjustment of a replacement voltage regulator is likely since there will always be a difference in impedance between the manufacturer s test equipment and the aircraft s electrical system INSULATION OF ELECTRICAL EQUIPMENT In some cases electrical equipment is connected into a heavy current circuit perhaps as a control device or relay Such equipment is normally insulated from the mounting structure since grounding the frame of the equipment may result in a serious ground fault in the event of equipment internal failure Stranded 18 or 20 AWG wire should be used as a grounding strap to avoid shock hazard to equipment and personnel If the end connection is used for shock hazard the ground wire must be large enough to carry the highest possible current 0 1 to 0 2 ohms max Page 11 484 and 11 4 9 8 98 AC 43 13 1B BUS BARS Annually check bus bars for general condition cleanliness an
207. ls CLEANING AND PRESERVATION Annual cleaning of electrical equipment to remove dust dirt and grime is recommended Suitable solvents or fine abrasives that will not score the surface or remove the plating may be used to clean the terminals and mating surfaces if they are corroded or dirty Only cleaning agents that do not leave any type of residue must be used Components must be cleaned and preserved in accordance with the aircraft handbooks or manufacturer s instructions Avoid using emery cloth to polish commutators or slip rings because particles may cause shorting and burning Be sure that protective finishes are not scored or damaged when cleaning Ensure that metal to metal electrically bonded surfaces are treated at the interface with a suitable anti corrosive conductive coating and that the joint is sealed around the edges by restoring the original primer and paint finish Connections that must withstand a highly corrosive environment may be encapsulated with an approved sealant in order to prevent corrosion CAUTION Turn power off before cleaning Par 11 8 AC 43 13 1B BATTERY ELECTROLYTE CORROSION Corrosion found on or near lead acid batteries can be removed mechanically with a stiff bristle brush and then chemically neutralized with a 10 percent sodium bicarbonate and water solution For Nickel Cadmium NiCad batteries a 3 percent solution of acetic acid can be used to neutralize the electrolyte After neutra
208. lst Red The color coding is composed of threads interwoven in the cotton sheath that holds the strands of rubber cord together Two spiral threads are used for the year coding and one thread is used for the quarter of the year sheath e g yellow and blue would indicate that the cord was manufactured in 1994 during April May or June Shock struts of the spring oleo type should be examined for leakage smoothness of operation looseness between the moving parts and play at the attaching points The extension of the struts should be checked to make sure that the springs are not worn or broken The piston section of the strut should be free of nicks cuts and rust Air oil struts should undergo an inspection similar to that recommended for spring oleo struts In addition the extension of the strut should be checked to see that it conforms to the distance specified by the manufacturer If an air oil strut bottoms that is it is collapsed the gas charge and hydraulic fluid has been lost from the air chamber This is probably due to a loose or defective air valve or to defective O ring seals Par 9 1 Page 9 411 AC 43 13 1B CAUTION Before an air oil strut is removed or disassembled the air valve should be opened to make sure that all air pressure is removed Severe injury and or damage can occur as the result of disassembling a strut when even a small amount of air pressure is still in the air chamber The method for c
209. lt up by vacuum deposition and other techniques usually on a silicon chip and mounted in a suitable package intergranular corrosion the formation of corrosion along the grain boundaries within a metal alloy interlocked grained wood wood in which the fibers are inclined in one direction in a number of rings of annual growth then gradually reverse and are inclined in an opposite direction in succeeding growth rings then reverse again laminate a product obtained by bonding two or more laminae of the same material or of different materials laminated wood a piece of wood built up of plies or laminations that have been joined either with glue or with mechanical fastenings The term is most frequently applied where the plies are too thick to be classified as veneer and when the grain of all plies is parallel leakage field the magnetic field forced out into the air by the distortion of the field within a part caused by the presence of a discontinuity or change in section configuration linter the short fiber left on the cotton seed after ginning localizer that section of an ILS that produces the directional reference beam LORAN Long Range Navigation a radio navigation system utilizing master and slave stations transmitting timed pulses The time difference in reception of pulses from several stations establishes a hyperbolic line of position that may be identified on a LORAN chart By utilizing signals fro
210. ly ensure such dissipation on larger objects Higher resistances are permissible in connecting smaller objects to airframe structure BONDING INSPECTION Inspect for the following If there is evidence of electrical arcing check for intermittent electrical contact between conducting surfaces that may become a part of a ground plane or a current path Arcing can be prevented either by bonding or by insulation if bonding is not necessary The metallic conduit should be bonded to the aircraft structure at each terminating and break point The conduit bonding strap should be located ahead of the piece of equipment that is connected to the cable wire inside the conduit Bond connections should be secure and free from corrosion Bonding jumpers should be installed in such a manner as not to interfere in any way with the operation of movable components of the aircraft 9 8 98 Self tapping screws should not be used for bonding purposes Only standard threaded screws or bolts of appropriate size should be used Exposed conducting frames or parts of electrical or electronic equipment should have a low resistance bond of less than 2 5 millohms to structure If the equipment design includes a ground terminal or pin which is internally connected to such exposed parts a ground wire connection to such terminal will satisfy this requirement Refer to manufacturer s instructions Bonds should be attached directly to the basic aircraft s
211. m Plated Corrosion Cadmium Plated Cadmium Plated Plated Steel Resisting Steel Steel Steel Steel Corrosion Corrosion Resisting Corrosion Cadmium Plated Cadmium Plated Resisting Steel Resisting Steel Steel Steel Avoid connecting copper to magnesium Use washers having a conductive finished treated to prevent corrosion suggest AN960JD10L Par 11 190 Page 11 557 9 8 98 AC 43 13 1B TABLE 11 16 Bolt and nut bonding or grounding to flat surface WASHER TOT c n cii SCREW OR BOLT WASHER B TERMINAL LIMITED TO 4 LOCKNUT WASHER C Aluminum Terminal and Jumper Screw or bolt and nut plate Lock nut Washer B Washer C Aluminum Alloys Cadmium Plated Cadmium Plated Cadmium Plated Cadmium Plated Steel Steel Steel or Aluminum Steel or Aluminum Magnesium Alloys Cadmium Plated Cadmium Plated Magnesium Alloy None or Cadmium Plated Steel Steel Magnesium alloy Steel or Aluminum Steel Cadmium Cadmium Plated Cadmium Plated Cadmium Plated Cadmium Cadmium Plated Plated Steel Steel Steel Plated Steel Steel or Aluminum Steel Corrosion Corrosion Resisting Cadmium Plated Corrosion Cadmium Cadmium Plated Resisting Steel or Cadmium Steel Resisting Steel Plated Steel Steel or Plated Steel Aluminum Tinned Copper Terminal and Jumper Aluminum Alloy Cadmium Plated Cadmium Plated Cadmium Plated Aluminum Cadmium Steel Steel Steel Alloy Plated Steel Magnesium Alloy Steel Cadmium Cadmium Plated Cadmium Plated Cadmium Plated Cadmium Pla
212. m two pairs of stations a fix in position is obtained magnetic field the space around a source of magnetic flux in which the effects of magnetism can be determined marker beacon a radio navigation aid used in an instrument approach to identify distance to the runway As the aircraft crosses over the marker beacon transmitter the pilot receives accurate AC 43 13 1B Appendix 1 indication of the airplane s distance from the runway through the medium of a flashing light and an aural signal master switch a switch designed to control all electric power to all circuits in a system moisture content of wood weight of the water contained in the wood usually expressed in percentage of the weight of the kiln dry wood multiconductor cable consists of two or more cables or wires all of which are encased in an outer covering composed of synthetic rubber fabric or other material nick a sharp notch like displacement of metal surface nomex braid NOMEX is the trade name for a high temperature polyamide thread that is braided over the larger sizes 8 gage and larger of many of the military specification wires It can be encountered in either an off white or black green color normalizing reforming of the grain structure of a metal or alloy by proper heat treatment to relieve internal stresses open circuit an incomplete or broken electrical circuit open grained wood common classification of p
213. manufacturer s direction followed with hospital supervised stomach treatment HYDRAULIC SYSTEM MAINTENANCE PRACTICES The maintenance of hydraulic and pneumatic systems should be performed in accordance with the aircraft manufacturer s instructions The following is a summary of general practices followed when dealing with hydraulic and pneumatic systems Service The servicing of hydraulic and pneumatic systems should be performed at the intervals specified by the manufacturer Some components such as hydraulic reservoirs have servicing information adjacent to the component When servicing a hydraulic reservoir make certain to use the correct type of fluid Hydraulic fluid type can be identified by color and smell however it is good practice to take fluid from the original marked container and then to check the fluid by color and smell for verification Fluid containers should always be closed except when fluid is being removed Contamination Control Contamination both particulate and chemical is detrimental to the performance and life of components in the aircraft hydraulic system Contamination enters the system through normal wear of components by ingestion through external seals during servicing or maintenance when the system is opened to replace repair components etc To control the particulate contamination in the system filters are installed in the pressure line in the return line and in the pump case drain line
214. marker beacon system must be operationally evaluated in VFR when an ILS runway is available The receiver sensitivity switch must be placed in LOW SENSE the normal setting Marker audio must be adequate Ground test equipment must be used to verify marker beacon operation Marker beacon with self test feature verify lamps audio and lamp dimming LONG RANGE NAVIGATION LORAN The LORAN has been an effective alternative to Rho Theta R Nav systems 9 8 98 Hyperbolic systems require waypoint designation in terms of latitude and longitude unlike original R Nav distance navigation systems which define waypoints in terms of distance Rho and angle Theta from established VOR or Tacan facilities Accuracy is better than the VOR Tacan system but LORAN is more prone to problems with precipitation static Proper bonding of aircraft structure and the use of high quality static wicks will not only produce improved LORAN system performance but can also benefit the very high frequency VHF navigation and communications systems This system has an automatic test equipment ATE NOTE Aircraft must be outside of hangar for LORAN to operate Normally self test check units verification of position and loading of flight plan will verify operation verification of proper flight manual supplements and operating handbooks on board and proper software status can also be verified GLOBAL POSITIONING SYSTEM GPS The GPS is at the forefron
215. mechanisms Wheels Inspect the wheels periodicsally for cracks corrosion dents distortion and faulty bearings in accordance with the manufacturer s service information In 9 8 98 split type wheels recondition bolt holes which have become elongated due to some play in the through bolt by the use of inserts or other FAA approved means Pay particular attention to the condition of the through bolts and nuts Carefully inspect the wheels used with tubeless tires for damage to the wheel flange and for proper sealing of the valve The sealing ring used between the wheel halves should be free of damage and deformation When bolting wheel halves together tighten the nuts to the proper torque value Periodically accomplish an inspection to ensure the nuts are tight and that there is no movement between the two halves of the wheel Maintain grease retaining felts in the wheel assembly in a soft absorbent condition If any have become hardened wash them with a petroleum base cleaning agent if this fails to soften them they should be replaced Corrosion of wheels Remove all corrosion from the wheel half and inspect it to ensure that the wheel halves are serviceable Apply corrosion prevention treatments as applicable Prime with a zinc chromate primer or equivalent and apply at least two finish coats Dented or distorted wheels Replace wheels which wobble excessively due to deformation resulting from a severe side load impact In
216. missing or poor sealant at base of antenna correct installation signs of corrosion and the condition of paint bonding and grounding Check the bonding of each antenna from mounting base to the aircraft skin Tolerance 1 ohm maximum Test Equipment 1502B Metallic Time Do Main Reflectometer or equivalent Thruline Wattmeter Perform the antenna evaluation check using the domain reflectometer to determine the condition of the antenna and coax cables Refer to manufacturer s maintenance procedures Use thruline wattmeter as needed for addition evaluation Refer to manufacturer s maintenance procedures Check for the following Resistance Shorts Opens Par 12 12 Page 12 602 AC 43 13 1B Check the static dischargers wicks for physical security of mounting attachments wear or abrasion of wicks missing wicks etc assurance that one inch of the inner braid of flexible vinyl cover wicks extends beyond the vinyl covering assurance that all dischargers are present and securely mounted to their base assurance that all bases are securely bonded to skin of aircraft in order to prevent the existence in voltage level differences between two surfaces signs of excessive erosion or deterioration of discharger tip lighting damage as evidenced by pitting of the metal base and megohm value of static wick itself as per manufacturer s instructions t should not be open Subsequent inspection mus
217. mpass readings are not identical then the mechanic should make up two separate compass correction cards One with all the equipment on and one with the equipment off PNEUMATIC GYROS Venturi Systems The early gyro instruments were all operated by air flowing out of a jet over buckets cut into the periphery of the gyro rotor A venturi was mounted on the outside of the aircraft to produce a low pressure or vacuum which evacuated the instrument case and air flowed into the instrument through a paper filter and then through a nozzle onto the rotor Par 12 37 AC 43 13 1B Venturi systems have the advantage of being extremely simple and requiring no power from the engine nor from any of the other aircraft systems but they do have the disadvantage of being susceptible to ice and when they are most needed they may become unusable There are two sizes of venturi tubes those which produce four inches of suction are used to drive the attitude gyros and smaller tubes which produce two inches of suction are used for the turn and slip indicator Some installations use two of the larger venturi tubes connected in parallel to the two attitude gyros and the turn and slip indicator is connected to one of these instruments with a needle valve between them A suction gage is temporarily connected to the turn and slip indicator and the aircraft is flown so the needle valve can be adjusted to the required suction at the instrument when
218. mperature connector contact surface of a wire bundle when approved by the OAM sizes should be suitably rated for the circuit load This may require an increase in wire size also Voltage derating is required when connectors are used at high altitude in Par 11 232 Page 11 577 9 8 98 nonpressurized areas Derating of the connectors should be covered in the specifications SPARE CONTACTS Future Wiring To accommodate future wiring additions spare contacts are normally provided Locating the unwired contacts along the outer part of the connector facilitates future access A good practice is to provide Two spares on connectors with 25 or less contacts 4 spares on connectors with 26 to 100 contacts and 6 spares on connectors with more than 100 contacts Spare contacts are not normally provided on receptacles of components that are unlikely to have added wiring Connectors must have all available contact cavities filled with wired or unwired contacts Unwired contacts should be provided with a plastic grommet sealing plug INSTALLATION Redundancy Wires that perform the same function in redundant systems must be routed through separate connectors On systems critical to flight safety system operation wiring should be routed through separate connectors from the wiring used for system failure warning It is also good practice to route a system s indication wiring in separate connectors from its failure warning circuits to the e
219. n equipment on at least one low high and mid band frequency NOTE Electromagnetic compatibility problems which develop after installation of this equipment may result from such factors as design characteristics of previously installed systems or equipment and the physical installation itself It is not intended that Par 11 115 Page 11 530 9 8 98 43 13 1 the equipment manufacturer should design for all installation environments The installing facility will be responsible for resolving any incompatibility between this equipment and previously installed equipment in the airplane The various factors contributing to the incompatibility should be considered NOTE Ground EMI test have consistently been found adequate for follow on approvals of like or identical equipment types irrespective of the airplane model used for the initial approval Radio frequency transmission devices such as wireless telephones must also be tested with respect to their transmission frequencies and harmonics IDENTIFICATION STENCILS AND PLACARDS ON ELECTRICAL EQUIPMENT Replace worn stencils and missing placards 11 109 11 114 RESERVED Par 11 115 Page 11 531 9 8 98 43 13 1B SECTION 9 ENVIRONMENTAL P MAINTENANCE AND OPERATIONS Wire bundles must be routed in accessible areas that are protected from damage from personnel cargo and maintenance activity They should not be routed in areas in where they are likely to be used as handholds
220. n a normal electrical charging system the battery s generator or alternator restores a battery to full charge during a flight of one hour to ninety minutes Mechanical Integrity Proper mechanical integrity involves the absence of any physical damage as well as assurance that hardware is correctly installed and the battery is properly connected Battery and battery compartment venting system tubes nipples and attachments when required provide a means of avoiding the potential buildup of explosive gases and should be checked periodically to ensure that they are securely connected and oriented in accordance with the maintenance manual s installation procedures Always follow procedures approved for the specific aircraft and battery system to ensure that the battery system is capable of delivering specified performance 9 8 98 Battery and Charger Characteristics The following information is provided to acquaint the user with characteristics of the more common aircraft battery and battery charger types Products may vary from these descriptions due to different applications of available technology Consult the manufacturer for specific performance data NOTE Under no circumstances connect a lead acid battery to a charger unless properly serviced Lead acid vented batteries have a two volt nominal cell voltage Batteries are constructed so that individual cells cannot be removed Occasional addition of water is required to replace w
221. n breathing oxygen when having the oxygen bottle charged Charging High Pressure Oxygen Cylinders The following are recommended procedures for charging high pressure oxygen cylinders from a manifold system either permanently installed or trailer mounted CAUTION Never attempt to charge a low pressure cylinder directly from high pressure manifold system or cylinder Inspection Do not attempt to charge oxygen cylinders if any of the following discrepancies exist 9 8 98 Par 9 50 Inspect for contaminated fittings on the manifold cylinder or outside filler valve If cleaning is needed wipe with stabilized trichlorethylene and let air dry Do not permit the solvent to enter any internal parts Check the hydrostatic test date of the cylinder DOT regulations require ICC or DOT 3AA_ designation cylinders to be hydrostatic tested to5 3 their working pressure every 5 years Cylinders bearing designation ICC or DOT 3HT must hydrostatic tested to5 3 their working pressure every 3 years and retired from service 15 years or 4 380 filling cycles after the date of manufacture whichever occurs first If the cylinder is completely empty do not charge An empty cylinder must be removed inspected and cleaned before charging Charging Connect the cylinder valve outlet or the outside filler valve to the manifold Slowly open the valve of the cylinder to be charged and observe the pressure on the gauge of the ma
222. n small areas 6 square inches or less of light surface type corrosion may require propeller removal reconditioning by a qualified propeller repair facility _ When intergranular corrosion is present the repair can be properly accomplished only by an appropriately certificated propeller repair facility Corrosion pitting under propeller blade decals should be removed as described in the propeller manufacturer s SB s and applicable airworthiness directives AD Unauthorized straightening of blade following a ground strike or other damage can create conditions that lead to immediate blade failure These unapproved major repairs may sometimes be detected by careful inspection of the leading edges and the flat face portion of the blade Any deviation of the flat portion such as bows or kinks may indicate Par 8 93 Page 8 404 AC 43 13 1B unauthorized straightening of the blade Sighting along the leading edge of a propeller blade for any signs of bending can provide evidence of unapproved blade straightening Blades should be examined for any discoloration that would indicate unauthorized heating Blades that have been heated for any repair must be rejected since only cold straightening is authorized blades showing evidence of unapproved repairs should be rejected When bent propellers are shipped to an approved repair facility for inspection and repair the propeller should never be straightened by field servi
223. n tests when applicable will be accomplished during storage and after installation in an aircraft in accordance with the manufacturer s specifications and or FAA approved procedures Accessory items will be installed during these inspections A raft knife will be attached by a 24 inch nylon lanyard to the mooring eye located above the cylinder case to enable rapid cutting of the mooring line LIFE RAFT INSPECTIONS Inspection of life rafts should be performed in accordance with the manufacturer s Page 9 436 specifications General inspection procedures to be performed on most life rafts are as follows CAUTION Areas where life rafts are inspected or tested must be smooth free of splinters sharp projections and oil stains Floors with abrasive characteristics such as concrete or rough wood will be covered with untreated tarpaulins or heavy clean paper Inspect life rafts for cuts tears or other damage to the rubberized material If the raft is found to be in good condition remove the CO bottle s and inflate the raft with air to a pressure of 2 psi The air should be introduced at the fitting normally connected to the CO bottle s After at least 1 hour to allow for the air within the raft to adjust itself to the ambient temperature check pressure and adjust if necessary to 2 psi and allow the raft to stand for 24 hours If after 24 hours the pressure is less than 1 psi examine the raft for leakage by
224. nce a nut will advance in one revolution of the screw in a single thread pitch distribution is the gradual twist in the propeller blade from shank to tip pitted small irregular shaped cavities in the surface of the parent material usually caused by corrosion chipping or heavy electrical discharge pitting the formation of pockets of corrosion products on the surface of a metal plastic an organic substance of large molecular weight which is solid in its finished state and at some stage during its manufacture or its processing into a finished article can be shaped by flow polyester braid a plastic braiding thread when used as the outer surface of a wire provides a cloth like appearance polyimide tape a plastic film commonly referred to by the trade name KAPTON The tape has a dark brown color and is frequently coated with a polyimide varnish that has a very distinct mustard yellow color At times the spiral edge of the outermost tape is apparent under the varnish topcoat It may be used for wire insulation Total polyimide tape insulated wire constructions are inactive for new design on military aircraft and are subject to the procedures defined in FAA Advisory Circular AC 29 2A Change 2 Paragraph 29 1359 in Civil Aircraft AC 43 13 1B Appendix 1 polyimide varnish a liquid form of polyimide that is applied to the outer surface of a wire through the process of repeated dipping through the varnish bath w
225. nd display panel MCDU nnultipurpose control and display unit MDE nmodern digital electronics MEC amain equipment center main engine control MEG or MEGA Qunillion MEK nmethylethylketone MEM memory METO Maximum except take off MF mf medium frequency 300 kHz to 3 MHz MHz megahertz MIC 3nicrophone AC 43 13 1B Appendix 2 MICRO P nicroprocessor MIG riretal inert gas MILLI one one thousandth 0 001 BCN nmarker beacon MS nnilitary standard MSDS Material Safety Data Sheets MSEC ms milliseconds MSG nessage MTBF mean time between failure MUX nultiplexer mV anillivolts NAS National Aerospace Standard NAV navigation NC normally closed not connected no connection NDB nondirectional beacon NDI Nondestructive Inspection NEG egative NSEC ns nanoseconds NTSB National Transportation Safety Board NVM nonvolatile memory OAM original aircraft manufacturer OBS omni bearing selection OC overcurrent OEM criginal equipment manufacturer OF over frequency OVV or OV overvoltage OVVCO or OVCO overvoltage cutout P S parallel to series PA passenger address power amplifier PARA SER parallel to serial PCU passenger control unit power control unit PFD permanent magnet generator PMA Parts Manufacturer Approval POS positive POT potentiometer plan of test PR power relay PRL parallel PROM programmable read o
226. nd service life and do not have to be age controlled First Aid Kit Inspect each kit prior to flight to ensure that the seal is intact the kits have not been tampered with or opened and check the date when the kit contents should be inspected 120 day interval and containing the following 9 8 98 1 Case First Aid Kit empty 1 Bottle Benzalkonium Chloride Zinc Tinted 1 1000 2cc 1 Package Sodium Chloride Sodium Bicarbonate Mix 4 5 gm 1 Bandage each Gauze amp Compress 2 inches x 6 yd 2 Dressings First Aid 4 inches x 7 inches 1 Package Bandages Absorbent amp Adhesive 3 4 inch x 3 inches 3 Bottles Snap On Cap Plastic Tablet and Capsule Round issued empty to be used as needed by user 1 Tube Lipstick Anti Chap and 1 bottle Water Purification Tablets Iodine 8 mg 50 If the seal is found to be broken or there is evidence of tampering the kit should be opened and inspected to ensure that all components are included and undamaged After such inspection the kit should be resealed To reseal the kit use a wire and lead seal according to the manufacturer s specifications Pass the wire through grommets or opposite flaps bend the wire back and force each end through the middle of the lacing cord on each side of the square knot Pass the ends of the wire through the holes in the lead seal draw the wire taut and compress the seal Mirror Reflector Check the reflector for defective reflection s
227. nent ballast do not remove It is not Forward p Moments counterclockwise Wheel pants added 6 at 1 DATUM 1 Battery removed 7 244 at 29 AC 43 13 1B desirable to install permanent ballast by pouring melted lead into the tail post or longerons due to difficulties that may be encountered in subsequent welding repair operations It should be noted that the installation of permanent ballast results in an increase of aircraft empty weight See figure 10 19 for ballast computation The local strength of the compartment in which the ballast is carried and the effect of the ballast on aircraft weight and balance should be investigated when disposable ballast is carried Rearward Moments clockwise Battery added 4294 at 13 Landing light removed 714 at 4 Weight x Arm Moment f ADDED Item 204 wheel pants Item 302b Batter REMOV ED Item 302a Batter 24 Item 303 Landing light 1 6 29 This condition is shown properly entered on a sample weight and balance report on Figure 10 18 under Equipment Change IGURE 10 16 Example of moment and weight changes resulting from equipment changes MAKE MA 700 MODEL A SERIALz 0000 DATUM IS leading edge of wing REGISTRATION 234 COMPUTE AS FOLLOWS IF AIRCRAFT WEIGHED Par 10 22 Page 10 477 9 8 98 AC 43 13 1B Leveling means level top longeron bet
228. neral term applied to the process of electrically connecting two or more conductive objects In aircraft the purpose of bonding except as applied to individual connections in the wiring and grounding systems is to provide conductive paths for electric currents This is accomplished by providing suitable low impedance connections joining conductive aircraft components and the aircraft structure Another purpose of bonding is to ensure the safe passage of current caused by lightning or static electricity through the aircraft structure borescope a long tubular optical instrument designed for remote visual inspection of surfaces brashness a condition of wood characterized by low resistance to shock and by an abrupt failure across the grain without splintering braze welding a welding process variation which a filler metal having a liquidus above 450 C 840 F and below the solidus of the base metal is used Unlike brazing in braze welding the filler metal is not distributed in the joint by capillary action brazing the joining of two pieces of metal by wetting their surface with molten alloy of copper Zinc or tin bus or bus bar solid copper strips to carry current between primary and secondary circuits also used as jumpers butt joint a joint between two members aligned approximately in the same plane butyrate dope a finish for aircraft fabric consisting of a film base of cellulose fibers dissolved
229. ng damage Check all safety wire and other locking devices especially at the main packing gland nuts When assembling shock struts use the correct type and number of new O rings Chevron seals and backup rings Use only the correct filler valve core assembly and follow the manufacturers instructions when servicing with fluid and air Either too much or too little air or oil will affect aircraft handling characteristics during taxi takeoff and landing and can cause structural overloads Shock cords and rubber discs deteriorate with age and exposure When this type of shock absorber is used inspect for general condition i e cleanliness stretching fraying and broken strands These components should be kept free of petroleum products as they accelerate deterioration of the rubber Nose Gear Assembly Inspection of the steering mechanism should include torque links scissors torque tubes control rods and rod end bearings shimmy dampers cables and turning stops In addition check all nose landing gear components including mud scrapers and slush deflectors for damage Towing of some aircraft with the rudder locks installed may cause damage to the steering linkage rudder control system Par 9 4 Page 9 413 AC 43 13 1B Exceeding the steering or towing stop limits should be followed by a close inspection of the entire nose steering assembly A broken steering stop will allow turning beyond the design
230. ng to eventual battery failure due to low capacity The state of charge of a NiCad battery cannot be determined by measuring the specific gravity of the potassium hydroxide electrolyte The electrolyte specific gravity does not change with the state of charge The only accurate way to determine the state of charge of a NiCad battery is by a measured discharge with a NiCad battery charger and following the manufacturer s instructions After the battery has been fully charged and allowed to stand for at least two hours the fluid level may be adjusted if necessary using distiled or demineralized water Because the fluid level varies with the state of charge water should never be added while the battery is installed in the aircraft Overfilling the battery will result in electrolyte spewage during charging This will cause corrosive effects on the cell links self discharge of the battery dilution of the electrolyte density possible blockage of the cell vents and eventual cell rupture Lead acid batteries are usually charged by regulated DC voltage sources This allows maximum accumulation of charge in the early part of recharging Constant current battery chargers are usually provided for NiCad batteries because the NiCad cell voltage has a negative temperature coefficient With a constant voltage charging source a NiCad battery 9 8 98 having a shorted cell might overheat due to excessive overcharge and undergo a thermal runaw
231. nifold system Slowly open the valve of the cylinder on the manifold system having the lowest pressure and allow the pressure to equalize Close the cylinder valve on the manifold system and slowly open the valve of the cylinder having the next highest pressure Continue this procedure until the cylinder has been charged in accordance with table 9 5 Page 9 454 AC 43 13 1B Close all valves on the manifold system Close the valve on the filled cylinder and remove the cylinder from the manifold Using a leak detector test for leakage around the cylinder valve threaded connections If leakage is present discharge the oxygen and return the cylinder to the facility for repair Let the cylinder stabilize for a period of at least 1 hour and then recheck the pressure Make any necessary adjustments in the pressure Charging of Low Pressure Oxygen Systems and Portables For recharging a low pressure aircraft oxygen system or portable cylinders it is essential that the oxygen trailer or cart have a pressure reducing regulator Military types E 2 or C 1 reducing regulators are satisfactory These types of regulators reduce the large cylinder pressure from 2 000 psi to a line pressure of 450 psi A welding pressure reducing regulator is not satisfactory CAUTION When refilling the low pressure system or portable cylinders open the oxygen filler tank valve slowly to allow the system or portable cylinders to be filled at
232. nkcase The air was then exhausted overboard Aircraft equipped with rubber deicer boots used this discharge air to inflate the boots But before it could be used this air was passed through a second stage of oil separation and then to the distributor valve and finally to the boots See figure 12 2 The airflow through the instruments is controlled by maintaining the suction in the instrument case at the desired level with a suction relief valve mounted between the pump and the instruments This valve has a Par 12 38 Page 12 613 spring loaded poppet that offsets to allow cabin air to enter the pump and maintain the correct negative pressure inside the instrument case The more modern vacuum pumps are of the dry type These pumps use carbon vanes and do not require any lubrication as the vanes provide their own lubrication as they wear away at a carefully predetermined rate Other than the fact that they do not require an oil separator systems using dry air pumps are quite similar to those using a wet pump One slight difference however is in the need for keeping the inside of the pump perfectly clean Any solid particles drawn into the system through the suction relief valve can damage one of the carbon vanes and this can lead to destruction of the pump as the particles 9 8 98 SUCTION REDUCER GYRO HORIZON SUCTION REGULATOR OIL AC 43 13 1B P AIR IN TURN amp SLIP CENTRAL INDICATOR m AIR
233. nly memory PROX proximity PSEU proximity switch electronic unit PSI pounds per square inch PWR power PWR SPLY power supply QPL Qualified Products List QTY quantity r t teceiver transmitter RA radio altimeter radio altitude RAD tadio RAIND radio altimeter indicator RAM random access memory RART radio altimeter receiver transmitter 9 8 98 RAT am air turbine RCCB remote control circuit breaker RCL tecall RCVR teceiver RCVR XMTR teceiver transmitter RDMI 1zadio distance magnetic indicator RF rf radio frequency RFI 1adio frequency interference RLS temote light sensor RMI 1zadio magnetic indicator rpm revolution per minute RTV oom temperature vulcanizing SAE Society of Automotive Engineers SA T static air temperature SATCOM satellite communication SCR silicon controlled rectifier SDI source destination identifier SELCAL selective calling system SER DL serial data link SG symbol generator SITA Soci t International de Telecommunications Aeronautiques SMA W shielded metal arc welding SMD surface mounted device SNR signal to noise ratio SOL solenoid SOLV solenoid valve SOM start of message SOT start of transmission SPKR speaker SPR software problem report SQL squelch SSB single sideband SSID Supplemental Documents SSM sign status matrix ST synchro transmitter STAT INV static inverter STBY standby STC S
234. nsert tube and repair by using one union and two sets of connection fittings 9 8 98 TABLE 9 2 Tube data Wrench torque for tightening AN 818 Nut pound inch Dash Nos Tubing OD Aluminum alloy tubing Steel tubing Ref inches Minimum Maximum Minimum Maximum Replacement of Flexible Lines When replacement of a flexible line is necessary use the same type size part number and length of hose as the line to be replaced Check TSO requirements If the replacement of a hose with a swaged end type fitting is necessary obtain a new hose assembly of the correct size and composition Certain synthetic oils require a specially compounded synthetic rubber hose which is compatible Refer to the aircraft manufacturer s service information for the correct part number for the replacement hose If the fittings on each end are of the correct type or sleeve type a replacement may be fabricated as shown in figure 9 8 Before cutting new flexible wire braided hose to the proper size tape the hose tightly with masking tape and cut in the center of the masking tape to prevent fraying The use of a mandrel will prevent cutting the inside of the hose when inserting the fittings Typical aircraft hose specifications and their uses are shown in table 9 3 Install hose assemblies without twisting See figure 9 9 A hose should not be stretched tight between two fittings as this will result in overstressing and eventual failure The length of hose s
235. nsformer XFR transfer XMIT transmit XMTR transmitter XPDR transponder U U U U U U U U 9 8 98 AC 43 13 1B Appendix 3 APPENDIX 3 METRIC BASED PREFIXES AND POWERS OF 10 quintillionth of 10 times Fem f quadrllionthof 107 times Pico p oruu trillionth of 107 times Nano n or mg billionth of 107 times Micro millionth of 10 times Milli m thousandth of P 1107 Ceni c hundredth of 107 times Deci d tenthof l0 tims k Jump e _ Deka da tentimes f 10 times Hecto h hundredtimes l0 time Kilo k thousandtimes 10 times Mega M milliontimes _ 10 times Giga G orkM biliontims f 10 times Tera trillion 100 times 9 8 98 AC 43 13 1B Appendix 3
236. ntamination in the system Such noises can also be caused by a faulty pressure regulator another pressure control unit or a lack of proper accumulator action Maintenance of hydraulic system components involves a number of standard practices together with specialized procedures set forth by manufacturers such as the replacement of valves actuators and other units including tubing and hoses Care should be exercised to prevent system contamination damage to seals packings and other parts and to apply proper torque in connecting fittings When Par 9 29 Page 9 427 AC 43 13 1B installing fittings valves etc always lubricate the threads with hydraulic fluid Overhaul of hydraulic and pneumatic units is usually accomplished in approved repair facilities however replacement of seals and packings may be done from time to time by technicians in the field When a unit is disassembled all O ring and Chevron seals should be removed and replaced with new seals The new seals must be of the same material as the original and must carry the correct manufacturer s part number No seal should be installed unless it is positively identified as the correct part and the shelf life has not expired When installing seals care should be exercised to ensure that the seal is not scratched cut or otherwise damaged When it is necessary to install a seal over sharp edges the edges must be covered with shim stock plastic sheet or elect
237. nufacturers to follow the wire material part number with the five digit letter C A G E code identifying the wire manufacturer Existing installed wire that needs replacement can thereby be identified as to its performance capabilities and the inadvertent use of a lower performance and unsuitable replacement wire avoided The method of identification should not impair the characteristics of the wiring CAUTION Do not use metallic bands in place of insulating sleeves Exercise care when marking coaxial or data bus cable as deforming the cable may change its electrical characteristics WIRE IDENTIFICATION To facilitate installation and maintenance original wire marking identification is to be retained The wire identification marks should consist of a combination of letters and numbers that identify the wire the circuit it belongs to its gauge size and any other information to relate the wire to a wiring diagram All markings should be legible in size type and color IDENTIFICATION AND INFORMATION RELATED TO THE WIRE AND WIRING DIAGRAMS The wire identification marking should consist of similar information to relate the wire to a wiring diagram Page 11 562 PLACEMENT OF IDENTIFICATION MARKINGS Identification markings should be placed at each end of the wire and at 15 inch maximum intervals along the length of the wire Wires less than 3 inches long need not be identified Wires 3 to 7 inches in length should be ident
238. nuous current of less than 0 5 amps A suitable method of rating switches for use on logic load devices is specified in ANSI EIA 5200000 General specification for special use electromechanical switches of certified quality TABLE 11 5 Selection of contact material Supply Voltage gold or silver gold or bifurcated gold bifurcated gold 0 001 0 01 0 5 Current Amperes 1 00 NOTES 1 If sulfide moisture or any form of contamination is present a sealed switch should be used The degree of sealing required environmental or hermetic is dependent upon the environment in which the switch is intended to be operated If particle contamination in any form is likely to reach the contacts bifurcated contacts should be used Low voltage high current loads are difficult to predict and may result in a combined tendency of noncontact sticking and material transfer High voltage high current applications may require the use of Silver Nickel contacts Page 11 498 9 8 98 Typical low level load devices have a voltage of less than 0 5 volts and a continuous current of less than 0 5 amps A suitable method of rating switches for use on logic load devices is specified in ANSI EIA 5200000 Shock and Vibration Electromechanical switches toggle switches are most susceptible to shock and vibration in the plane that is parallel to contact motion Under these conditions the switch contacts may momentarily separat
239. ny cylinders that show signs of abuse dents bulges cracks distortion damaged threads or defects which might render them unsafe Typical examples of oxygen cylinder damage are shown in figure 9 14 When replacing an oxygen cylinder be certain that the replacement cylinder is of the same size and weight as the one removed Par 9 46 Page 9 450 9 8 98 THREAD DAMAGE FIGURE 9 14 Oxygen cylinder damage NOTE Cylinders having greater weight or size will require strengthened cylinder mounting brackets and a reevaluation to determine that the larger or heavier cylinder will not interfere with adjacent systems components or structural members and that the strength of attaching structure is adequate and any additional weight will be computed into the aircraft s weight and balance report Replace or repair any cylinder mounting brackets that show signs of wear Visible cracks may be welded in accordance with manufacturers standards Replace the cylinder straps or clamps that show wear or abuse For typical mounting bracket cracks and failure see figure 9 15 CHECK FOR LOOSE RIVET CHECK FOR CRACKS IN COVER PLATE FIGURE 9 15 Cylinder brackets and clamps Par 9 49 Page 9 451 AC 43 13 1B Lines and Fittings Replace any oxygen line that is chafed rusted corroded dented cracked or kinked Clean oxygen system fittings showing signs of rusting or corrosion in the threaded area To accomplish this
240. ny stationary connection in a system is not permitted and if found it should be repaired A small amount of fluid seepage may be permitted on actuator piston rods and rotating shafts In a hydraulic system a thin film of fluid in these areas indicates that the seals are being properly lubricated When a limited amount of leakage is allowed at any Par 9 28 Page 9 426 AC 43 13 1B point it is usually specified in the appropriate manual Tubing should not be nicked cut dented collapsed or twisted beyond approved limits The identification markings or lines on a flexible hose will show whether the hose has been twisted See figure 9 9 All connections and fittings associated with moving units must be examined for play evidencing wear Such units should be in an unpressurized condition when they are checked for wear Accumulators must be checked for leakage air or gas preload and position If the accumulator is equipped with a pressure gauge the preload can be read directly An operational check of the system can be performed using the engine driven pump an electrically operated auxiliary pump if such a pump is included in the system or a ground test unit The entire system and each subsystem should be checked for smooth operation unusual noises and speed of operation for each unit The pressure section of the system should be checked with no subsystems to see that pressure holds for the required time without t
241. o coats of light cement and three coats of heavy cement to each surface Rubber coated tape and seam crossover patches with protective backing do not require cement Each coat of cement should be thoroughly dry to the touch before the next coat is applied Start the bonding of fabric surfaces while the last coat of cement is slightly tacky To ensure proper adhesion when bonding two cemented surfaces the areas to be bonded should remain tacky during application This is accomplished by brushing the cemented area with a cloth moistened with solvent NOTE If difficulty in the drying of heavy cement is encountered due to atmospheric conditions six additional coats of light cement may be substituted for the three coats of heavy cement After applying the patch thoroughly roll it with a hand roller rolling from the center to the outer edge to ensure that all air pockets are removed and a firm bond is secured Thoroughly dust with talc Allow to cure for 60 hours before performing leak tests and storing Inside Patches Cut a rectangular patch as shown in figure 9 13 allowing at least 1 1 2 inches to extend beyond the edge of the injury in all directions Mark the center line on the side of the patch that is to be attached to the raft Mark cross lines on each end of the patch 1 1 2 inches from the ends When the patch is applied to the injury on the inside the longitudinal edges of the injury will coincide with the P
242. o perform maintenance The calibration intervals for test equipment will vary with the type of equipment environment and use The accepted industry practice for calibration intervals is usually one year Considerations for acceptance of the intervals include the following Manufacturers recommendation for the type of equipment Repair facilitys past calibration history as applicable If the manufacturer s manual does not describe a test procedure the repair station must coordinate with the manufacturer to develop the necessary procedures prior to any use of the equipment 12 54 12 64 RESERVED Page 12 616 and 12 20 9 8 98 AC 43 13 1B Appendix 1 APPENDIX 1 GLOSSARY The following words and terms represent some of those that are often encountered in the field of aviation For a more complete list of definitions a mechanic or technician should consult an aviation dictionary abrasion resistant PTFE a solid insulation wall of PTFE with hard nonconductive grit positioned midway in the wall thickness and significantly improves the resistance of the PTFE material to damage from wear acetylene gas composed of two parts of carbon and two parts of hydrogen When burned in the atmosphere of oxygen it produces one of the highest flame temperatures obtainable acetylene regulator manually adjustable device used to reduce cylinder pressure to torch pressure and to keep the pressure constant They are neve
243. oated copper MIL W 22759 12 eo 20 Fluoropolymer insulated extruded TFE Nickel coated copper MiL W22759 14 600 135 Fluoropolymer insulated FEP PVF2 Tin coated copper MIL W 22759 15 135 Fluoropolymer insulated FEP PVF2 Silver plated high strength copper alloy MIL W 22759 18 t1 Fluoropolymer insulated extruded ETFE Tin coated copper MIL W 22759 19 150 Fluoropolymer insulated extruded ETFE Silver coated high strength copper alloy MIL W 22759 22 jc p x9 7 Fluoropolymer insulated extruded TFE Silver coated high strength copper alloy MIL W 22759 23 260 Fluoropolymer insulated extruded TFE Nickel coated high strength copper alloy MIL W 22759 32 150 Fluoropolymer insulated crosslinked Tin coated copper modified ETFE MIL W 22759 33 200 Fluoropolymer insulated crosslinked Silver coated high strength copper modified ETFE alloy MIL W 22759 44 200 Fluoropolymer insulated crosslinked Silver coated copper modified ETFE MIL W 22759 45 200 Fluoropolymer insulated crosslinked Nickel coated copper modified ETFE MIL W 22759 46 Fluoropolymer insulated crosslinked Nickel coated high strength modified ETFE alloy MIL W 81044 12 UM Crosslinked polyalkene Tin copper MIL W 81044 13 150 Crosslinked polyalkene Silver coated high strength copper alloy MIL W 81381 17 20 Fluorocarbon polyimide Silver coated copper MIL W 81381 18 eo 20 Fluorocarbon polyimide Nickel coated co
244. ocks plastic liners or rubber grommets are installed in holes bulkheads floors or structural members where it is impossible to install off angle clamps to maintain wiring separation In such cases additional protection in the form of plastic or insulating tape may be used Wires and cables in junction boxes panels and bundles are properly supported and laced to provide proper grouping and routing Page 11 523 Clamp retaining screws are properly secured so that the movement of wires and cables is restricted to the span between the points of support and not on soldered or mechanical connections at terminal posts connectors Wire and cables are properly supported and bound so that there is no interference with other wires cables and equipment Wires and cables are adequately supported to prevent excessive movement in areas of high vibration Insulating tubing is secured by tying tie straps or with clamps Continuous lacing spaced 6 inches apart is not used except in panels and junction boxes where this practice is optional When lacing is installed in this manner outside junction boxes should be removed and replaced with individual loops Do not use tapes such as friction or plastic tape which will dry out in service produce chemical reactions with wire or cable insulation or absorb moisture Insulating tubing must be kept at a minimum and must be used to protect wire and cable from abrasion chafing ex
245. od then swells and because expansion is limited by the bolts extending between the two flanges some of the wood fibers become crushed Later when the propeller dries out during dry weather or due 9 8 98 AC 43 13 1B TABLE 8 2 Sample manufacturer s propeller inspection checklist Nature of Inspection Engine Operating Hours PROPELLER GROUP Inspect Check propeller broken corrosion mounting bolts safety for and oil Lubrication Brackets for Check torque if safety is 0 0 ooo for cracks and Rotate blades of constant speed propeller and check for tightness in hub pilot 9 Remove constant crankshaft 10 deterioration Speed propeller installation to heat from the engine a certain amount of propeller hub shrinkage takes place and the wood no longer completely fills the space between the two hub flanges Consequently the hub bolts become loose In flight tip failures may be avoided by frequent inspections of the metal cap leading edge strip and surrounding areas Inspect for such defects as looseness or slipping separation of soldered joints loose screws loose rivets breaks cracks eroded sections and corrosion Inspect for separation between the metal leading edge and the cap which would indicate the cap is moving outward in the direction of centrifugal force This condition is often accompanied by di
246. of the tested RPM replace it 8 96 8 106 RESERVED Par 8 107 Page 8 406 9 8 98 Par 8 107 AC 43 13 1B SECTION 6 PROPELLER TRACKING AND VIBRATION GENERAL To ensure smooth powerplant operations first start with a properly installed propeller Each propeller should be checked for proper tracking blades rotating in the same plane of rotation Manufacturer s recommendations should in all cases be followed PROPELLER TRACKING CHECK The following is a simple procedure that can be accomplished in less than 30 minutes Chock the aircraft so it cannot be moved Remove one spark plug from each cylinder This will make the propeller easier and safer to turn Rotate one of the blades so it is pointing down Place a solid object e g a heavy wooden block that is at least a couple of inches higher off the ground than the distance between the propeller tip and the ground next to the propeller tip so that it just touches see figure 8 30 or attach a pointer indicator to the cowling itself Rotate the propeller slowly to see if the next blade tracks through the same point touches the block pointer Each blade track should be within 1 16 inch plus or minus from the opposite blade s track If the propeller is out of track it may be due to one or more propeller blades being bent a bent propeller flange or propeller mounting bolts that are either over or under torqued An out of track propeller will cause
247. olds the blades firmly approximately 30 40 000 Ibs against blade bearings Cabin vibration can sometimes be improved by reindexing the propeller to the crankshaft The propeller can be removed rotated 180 and re installed 9 8 98 AC 43 13 1B The propeller spinner can be a contributing factor to This condition is normally caused by inadequate an out of balance condition An indication of this shimming of the spinner front support or a cracked or would be a noticeable spinner wobble while the deformed spinner engine is running Par 8 109 Page 8 408 9 8 98 AC 43 13 1B COWLING FIXTURE FIGURE 8 30 Propeller tracking wood block or cowling fixture shown 8 110 8 129 RESERVED Par 9 1 Page 9 409 9 8 98 Par 9 1 AC 43 13 1B CHAPTER 9 AIRCRAFT SYSTEMS AND COMPONENTS SECTION 1 INSPECTION AND MAINTENANCE OF LANDING GEAR GENERAL The landing gear on aircraft may be fixed or retractable A fixed gear may be wheels floats or skis and for amphibians a combination of floats and wheels Retractable gear on aircraft is usually operated with hydraulic or electric power although some models of light general aviation aircraft have manual retract systems operated by a lever in the cockpit In addition to the normal operating system emergency systems are usually provided to ensure that the landing gear can be lowered in case of main system failure Emergency systems consist of backup hyd
248. om one source to another and can be a major problem in digital signaling Current Return Paths The design of the ground return circuit should be given as much attention as the other leads of a circuit A requirement for proper ground connections is that they maintain an impedance that is essentially constant Ground return circuits should have a current rating and voltage drop adequate for satisfactory operation of the connected electrical and electronic equipment EMI problems that can be caused by a system s power wire can be reduced substantially by locating the associated ground return near the origin of the power wiring e g circuit breaker panel and routing the power wire and its ground return in a twisted pair Special care should be exercised to ensure replacement on ground return leads The use of numbered insulated wire leads instead of bare grounding jumpers may aid in this respect In general equipment items should have an external ground connection even when internally grounded Direct connections to a magnesium which may create a fire hazard structure must not be used for ground return Heavy Current Grounds Power ground connections for generators transformer rectifiers batteries external power receptacles and other heavy current loads must be attached to individual grounding brackets that are attached to aircraft structure with a proper metal to metal bonding attachment This attachment and the surrounding str
249. on of the aircraft The tape unit is fire resistant and contains a radio transmitter to help crash investigators locate the unit under water Inspection Operational checks include Check special sticker on front of the flight data recorder for the date of the next tape replacement if applicable Remove recorder magazine and inspect tape for the following broken or torn tape proper feed of tape and all scribes were recording properly for approximately the last hour of flight Conditions for tape replacement as applicable There is less than 20 hours remaining in the magazine as read on the tape remaining indicator Tape has run out Broken tape After hard landings and severe air turbulence have been encountered as reported by the pilots Page 12 607 9 8 98 After the same tape has been in use 1 year 12 months it must be replaced Ensure that a correlation test has been performed and then recorded in the aircraft records Refer to the specific equipment manufacturer s manuals and procedures The state of the art Solid State Flight Data Recorder SSFDR is a highly flexible model able to support a wide variety of aeronautical radio incorporated ARINC configurations It has a Built In Test Equipment BITE that establishes and monitors the mission fitness of the hardware BITE performs verification after storage read after write of flight data and status condition of the memory These recor
250. on refer to the equipment manufacturer s maintenance manual WEATHER RADAR Ground performance shall include antenna rotation tilt indicator brilliance scan rotation and indication of received echoes It must be determined that no objectionable interference from other electrical electronic equipment appears on the radar indicator and that the radar system does not interfere with the operation of any of the aircraft s communications or navigation systems CAUTION Do not turn radar on within 15 feet of ground personnel or containers holding flammable or explosive materials The radar should never operate during fueling operations Do not operate radar system when beam may intercept larger metallic objects closer than 150 feet as crystal damage might occur Do not operate radar when cooling fans are inoperative Refer to the specific Radar System equipment manufacturer s manuals and procedures RADOME INSPECTION Inspection of aircraft having weather radar installations should include a visual check of the radome surface for signs of surface damage Page 12 608 AC 43 13 1B 9 8 98 receive and review transmitted data or to holes cracks chipping and peeling of paint etc Attach fittings and fastenings neoprene erosion caps transmit data to a bus user Before using an and lightening strips when installed should also be analyzer make sure that the bus language is inspected compatible with the bus analyzer For fu
251. onding and the application of related hardware GROUNDING Grounding is the process of electrically connecting conductive objects to either a conductive structure or some other conductive return path for the purpose of safely completing either a normal or fault circuit Types of Grounding If wires carrying return currents from different types of sources such as signals or DC and AC generators are connected to the same ground point or have a common connection in the return paths an interaction of the currents will occur This interaction may not be a problem or it could be a major nonrepeatable anomaly To minimize the interaction between various return currents different types of grounds should be identified and used As a minimum the design should use three ground types 1 AC returns 2 returns and 3 all others For distributed power systems the power return point for an alternative power source would be separated For example in a two AC generator one on the right side and the other on the left side system if the right AC generator were supplying backup power to equipment located in the left side left equipment rack the backup AC ground return should be labeled Right The return currents for the left Page 11 551 generator should be connected to a ground point labeled AC Left NOTE Mixing return currents from various sources should never be permitted to occur because noise will be coupled fr
252. or an interior of a CAR 3 aircraft that is used only in 14 CFR part 91 operations where smoking is not permitted is that the materials shall be flash resistant Reference CAR 3 388 For compartments in CAR 3 aircraft where smoking is permitted the wall and ceiling linings the covering of all upholstering floors and furnishings shall be flame resistant Such compartments should be equipped with an adequate number of self contained ash trays All other compartments shall be placarded against smoking Refer to CAR 3 388 If fabric is bought in bulk to refurbish the interior seats and ceiling liners for a CAR 3 aircraft used in part91 operations a manufacturer s statement declaring that the material meets the American Society for Testing and Materials ASTM or similar national standard for either flash resistance or flame resistance would be acceptable but only for a CAR 3 aircraft installation Refer to 14 CFR part 43 section 43 13 a manufacturer s statement is acceptable due to neither the Civil Aeronautics Administration CAA nor the Federal Aviation Administration FAA having published an FAA fire standard for either flash or flame resistance for interior materials for CAR 3 aircraft Since the FAA would accept and recognize a national Page 9 456 standard the mechanic would reference the manufacturer s statement and the national standard that the material meets in the aircraft s maintenance records If an
253. ors Table 11 4 provides an approximate method for derating nominal ratings to obtain reasonable switch efficiency and service life under reactive load conditions WARNING Do not use AC derated switches in DC circuits AC switches will not carry the same amperage as a DC switch TABLE 11 4 Switch derating factors Type of Load 28 VDC Inductive relay solenoid 28 VDC Resistive Heater Nominal System Voltage Derating Factor NOTES 1 To find the nominal rating of a switch required to operate a given device multiply the continuous current rating of the device by the derating factor corresponding to the voltage and type of load To find the continuous rating that a switch of a given nominal rating will handle efficiently divide the switch nominal rating by the derating factor corresponding to the voltage and type of load Par 11 53 AC 43 13 1B Low Energy Loads Switches rated for use at 28 VDC or more and at 1 0 amp or more generally have silver contacts In general silver contacts should not be used to control devices which have either a voltage less than 8 volts or a continuous current less than 0 5 amps unless the switch is specifically rated for use with low energy loads Table 11 5 provides general guidelines for selecting contact materials for low energy loads but is not applicable to hermetically sealed switches Typical logic load devices have a voltage of 0 5 volts to 28 volts and a conti
254. ot or tubing 11 140 11 145 RESERVED Par 11 146 Page 11 537 Par 11 146 9 8 98 43 13 1 SECTION 11 CLAMPING GENERAL Wires and wire bundles must be supported by using clamps meeting Specification MS 21919 or plastic cable straps in accessible areas if correctly applied within the restrictions of paragraph 11 158 Clamps and other primary support devices must be constructed of materials that are compatible with their installation and environment in terms of temperature fluid resistance exposure to ultraviolet UV light and wire bundle mechanical loads They should be spaced at intervals not exceeding 24 inches Clamps on wire bundles should be selected so that they have a snug fit without pinching wires as shown in figure 11 11 through figure 11 13 CAUTION The use of metal clamps on coaxial RF cables may cause problems if clamp fit is such that RF cable s original cross section is distorted Clamps on wire bundles should not allow the bundle to move through the clamp when a slight axial pull is applied Clamps on RF cables must fit without crushing and must be snug enough to prevent the cable from moving freely through the clamp but may allow the cable to slide through the clamp when a light axial pull is applied The cable or wire bundle may be wrapped with one or more turns of electrical tape when required to achieve this fit Plastic clamps or cable ties must not be used where their failure cou
255. ould be used for tire inspection Tread Wear Inspect the tires visually for remaining tread Tires should be removed when tread has worn to the base of any groove at any spot or to a minimum depth as specified by the tire or aircraft manufacturer Tires worn to fabric in the tread area should be removed regardless of the amount of tread remaining Uneven Wear If tread wear is excessive on one side the tire can be dismounted and turned around providing there is no exposed fabric Gear misalignment causing this condition should be corrected WARNING Do not probe cuts or embedded foreign objects while tire is inflated Tread Cuts Inspect tread for cuts and other foreign object damage and mark with crayon or chalk Remove tires that have the following Any cuts into the carcass ply Cuts extending more than half of the width of a rib and deeper than 50 percent of the remaining groove depth Weather checking cracking cuts and snags extending down to the carcass ply in the sidewall and bead areas Bulges in any part of tire tread sidewall or bead areas that indicate a separation or damaged tire Cracking in a groove that exposes fabric or if cracking undercuts tread ribs Flat Spots Generally speaking tires need not be removed because of flat spots due to skid or hydroplane burns unless fabric is exposed If objectionable unbalance results remove the tire from service Beads Inspect bead areas next to wheel flan
256. over or developer remains on the surface of the test part dye penetrant inspection an inspection method for surface cracks in which a penetrating dye is allowed to enter any cracks present and is pulled out of the crack by an absorbent developer A crack appears as a line on the surface of the developer edge grain edge grain lumber has been sawed parallel with the pith of the log and approximately at right angles to the growth rings that is the rings form an angle of 45 degrees or more with the surface of the piece electricity one of the fundamental quantities in nature consisting of elementary particles electrons and protons which are manifested as a force of attraction or repulsion and also in work that can be performed when electrons are caused to move a material agency which when in motion exhibits magnetic chemical and thermal effects and when at rest is accompanied by an interplay of forces between associated localities in which it is present electromagnet temporary magnet which is magnetized by sending current through a coil of wire wound around an iron core Electromagnetic Radio Frequency Interference EMI RFI frequency spectrum of electromagnetic radiation extending from subsonic frequency to X rays This term should not be used in place of the term Radio Frequency Interference RFI See radio frequency interference Shielding materials for the entire EMI spectrum are not readily available e
257. pacity of electrical wire both as a single wire in free air and when bundled into a harness It presents derating factors for altitude correction and examples showing how to use the graphical and tabular data provided for this purpose In some instances the wire may be capable of carrying more current than is recommended for the contacts of the related connector In this instance it is the contact rating that dictates the maximum current to be carried by a wire Wires of larger gauge may need to be used to fit within the crimp range of connector contacts that are adequately rated for the current being carried Figure 11 5 gives a family of curves whereby the bundle derating factor may be obtained Par 11 66 Page 11 507 AC 43 13 1B Effects of Heat Aging on Wire Insulation Since electrical wire may be installed in areas where inspection is infrequent over extended periods of time it is necessary to give special consideration to heat aging characteristics in the selection of wire Resistance to heat is of primary importance in the selection of wire for aircraft use as it is the basic factor in wire rating Where wire may be required to operate at higher temperatures due either to high ambient temperatures high current loading or a combination of the two selection should be made on the basis of satisfactory performance under the most severe operating conditions Maximum Operating Temperature The current that causes a temperature
258. pansion by specifying the conduit inner diameter I D about 25 percent larger than the maximum diameter of the wire bundle CONDUIT FITTINGS Wire is vulnerable to abrasion at conduit ends Suitable fittings should be affixed to conduit ends in such a manner that a smooth surface comes in contact with the wire When fittings are not used the end of the conduit should be flared to prevent wire insulation damage Conduit should be supported by use of clamps along the conduit run CONDUIT INSTALLATION Conduit problems can be avoided by following these guidelines Do not locate conduit where passengers maintenance personnel might use it as a handhold or footstep Par 11 248 Page 11 582 Provide drainholes at the lowest point in a conduit run Drilling burrs should be carefully removed Support conduit to prevent chafing against structure and to avoid stressing its end fittings RIGID CONDUIT Conduit sections that have been damaged should be repaired to preclude injury to the wires or wire bundle which may consume as much as 80 percent of the tube area Minimum acceptable tube bend radii for rigid conduit are shown in table 11 23 Kinked or wrinkled bends in rigid conduits are not recommended and should be replaced Tubing bends that have been flattened into an ellipse and the minor diameter is less than 75 percent of the nominal tubing diameter should be replaced because the tube area will have been reduced by at leas
259. pansion or in case a stud is broken Terminal strips that provide connection of radio and electronic systems to the aircraft electrical system should be inspected for loose connections metallic objects that may have fallen across the terminal strip dirt and grease accumulation etc These type conditions can cause arcing which may result in a fire or system failures Terminal Lugs Wire terminal lugs should be used to connect wiring to terminal block studs or equipment terminal studs No more than four terminal lugs or three terminal lugs and a bus should be connected to any one stud Total number of terminal lugs per stud includes a common bus bar joining adjacent studs Four terminal lugs plus a common bus bar thus are not permitted on one stud Terminal lugs should be selected with a stud hole diameter that matches the diameter of the stud However when the terminal lugs attached to a 9 8 98 stud vary in diameter the greatest diameter should be placed on the bottom and the smallest diameter on top Tightening terminal connections should not deform the terminal lugs or the studs Terminal lugs should be so positioned that bending of the terminal lug is not required to remove the fastening screw or nut and movement of the terminal lugs will tend to tighten the connection Copper Terminal Lugs Solderless crimp style copper wire terminal lugs should be used and conform to MIL T 7928 Spacers or washers should not be used betwe
260. past the seals In some installations minor seepage is normal Refer to the manufacturer s maintenance information What effect does the leak have on the operation of the system Know the system Does the leak of fluid create a hazard or affect surrounding installations A check of the system fluid and a knowledge of previous fluid replenishment is helpful Will the system function safely without depleting the reservoirs until the next inspection Hydraulic System Pressure Test When a flexible hose has been repaired or overhauled using existing hard worn and new hose material before the hose is installed on the aircraft it is recommended that the hose is tested to at least 1 5 system pressure A new hose can be operationally checked after it is installed in the aircraft using system pressure 9 8 98 AC 43 13 1B 1 Place hose in vise and cut to 2 Locate length of hose to be cut desired length using fine tooth off and slit cover with knife to wire hacksaw or cut off wheel braid After slitting cover twist off with pair of pliers see note below 3 Place hose in vise and screw 4 Lubricate inside of hose and socket on hose counterclockwise nipple threads liberally NOTE Hose assemblies fabricated per MIL H 8790 must have the exposed wire braid coated with a special sealant NOTE Step 2 applies to high pressure hose only CAUTION Do not use any petroleum product with hose designed wrench on hex of nippl
261. pe a narrow woven cotton or polyester tape used over aircraft fabric to reinforce it at the stitching attachments relay an electrically operated remote control switch 623 9 8 98 resin vast profusion of natural and increasingly synthetic materials used as adhesives fillers binders and for insulation resistance the opposition a device or material offers to the flow or current resonance method ringing of ultrasonic inspection a method of detecting material thickness or indications of internal damage by injecting variable frequency ultrasonic energy into a material A specific frequency of energy will produce the clearest indication of damage in a given thickness of material When the equipment is calibrated for a specific thickness and this thickness changes an aural or visual alert is given resonant frequency the frequency of a source of vibration that is exactly the same as the natural vibration frequency of the structure resonate a mechanical system is said to resonate when its natural vibration frequency is exactly the same as the frequency of the force applied When an object resonates at a particular frequency the amplitude in its vibration will increase immensely as that frequency is reached and will be less on either side of that frequency rib part of primary structure whose purpose is to maintain profile of airfoil and support fabric or thin wood covering sacrificial corrosion a m
262. perature and maximum current loading combinations Page 11 503 AC 43 13 1B 9 8 98 ZL S v 2 9o TUNLVUAMWAL YOLONGNOD GALVWLLSS ZL 3383HA WINWUOS ISN TUNLVUIINSL YOLONGNOD 33HOIH LV 271 HLON31 ANINYALAC OL Do OZ JO STAUNLVAIdNAL YOLONGNOD NO qasva SI HLON31 ALON YOLONGNOD 6SLLC Q31V Id NIL 0 LY MOTA SNONILNOD IWNVHO dOUd 39Vv110A AZIS TALM 9 94 SdWV 0C LV TAIM ON VW SdWV 0C LV FUM CI ON SdWV 0 LV TAIA 8 ON ATdWVXa I4 3 dAVX3 d5VI IOA LI YOWIO SNONILNOD lt 2 3 z m continuous flow FIGURE 11 2 Conductor chart Page 11 504 Par 11 66 AC 43 13 1B 9 8 98 21 S pEZ 171 752 Do FUNLVUIMNAL VOLONGNOD GALVWILSH CL JYJHM VINWUOd ASN 1 YOLONGNOSD N38HOIH LV 71 HLONAT INIWAILIA OL 2 0 JO STUNLVUINIL 30L900NOO NO 5 SI 17 HLONST HLON OE 0 59 34 YOLONGNOD 6 C V Id N 007 LV MOTA INSLLIPDISINI dOUd JOVLIOA AZIS TAIM dOHQ S9VLIOA AOVLTIOA LINDAIO 1444 NI HLONAT TAIM 3 Conductor chart intermittent flow FIGURE 11 Page 11 505 Par 11 66 9 8 98 AC 43 13 1B TABLE 11 9 Current carrying capacity and resistance of copper wire Continuous duty current amps Wires in bundles Max resistance Nominal groups harnesses or conduits See Note 1 ohms 1000ft 20 conductor Wire Conductor Temperature Rating
263. ple sources of electrical power as the result of corrosion of a ground connection or failure of the related fasteners may result in the loss of multiple systems and should be avoided by making the ground attachments at separate locations Bonds to thermally or vibration isolated structure require special consideration to avoid single ground return to primary structure The effect of the interconnection of the circuits when ungrounded should be considered whenever a common ground connection is used This is particularly important when employing terminal junction grounding modules or other types of gang grounds that have a single attachment point Page 11 552 9 8 98 Grounds for Sensitive Circuits Special consideration should be given to grounds for sensitive circuits For example Grounding of a signal circuit through a power current lead introduces power current return voltage drop into the signal circuit Running power wires too close will cause signal interference Separately grounding two components of a transducer system may introduce ground plane voltage variations into the system Single point grounds for signal circuits with such grounds being at the signal source are often a good way to minimize the effects of EMI lightning and other sources of interference BONDING The following bonding requirements must be considered Equipment Bonding Low impedance paths to aircraft structure are normally requir
264. points as shown in figure 11 9 This measurement may be exceeded provided there is no possibility of the wire group or bundle touching a surface that may cause abrasion Sufficient slack should be provided at each end to Permit replacement of terminals Prevent mechanical strain on wires Permit shifting of equipment for maintenance purposes POWER FEEDERS The power feeder wires should be routed so that they can be easily inspected or replaced They must be given special protection to prevent potential chafing against other wiring aircraft structure or components RF CABLE All wiring needs to be protected from damage However coaxial and triaxial cables are particularly vulnerable to certain types of damage Personnel should exercise care while handling or working around coaxial Coaxial damage can occur when clamped too tightly or when they are bent sharply normally at or near connectors Damage can also be incurred during unrelated maintenance actions around the coaxial cable Coaxial can be severely damaged on the inside without any evidence of damage on the outside Coaxial cables with solid center conductors should not be used Stranded center coaxial cables can be used as a direct replacement for solid center coaxial PRECAUTIONS Never kink coaxial cable Never drop anything on coaxial cable Never step on coaxial cable Never bend coaxial cable sharply Never loop coaxial cable tighter than the allowable bend ra
265. posure to fluid and other conditions which could affect the cable insulation However the use of insulating tubing for support of wires and cable in lieu of stand offs is prohibited Do not use moisture absorbent material as fill for clamps or adapters Ensure that wires and cables are not tied or fastened together in conduit or insulating tubing Ensure cable supports do not restrict the wires or cables in such a manner as to interfere with operation of equipment shock mounts Do not use tape tie straps or cord for primary support Make sure that drain holes are present in drip loops or in the lowest portion of tubing placed over the wiring Ensure that wires and cables are routed in such a manner that chafing will not occur against the airframe or other components 9 8 98 Ensure that wires and cables are positioned in such a manner that they are not likely to be used as handholds or as support for personal belongings and equipment Ensure that wires and cables are routed insofar as practicable so that they are not exposed to damage by personnel moving within the aircraft Ensure that wires and cables are located so as not to be susceptible to damage by the storage or shifting of cargo Ensure that wires and cables are routed so that there is not a possibility of damage from battery electrolytes or other corrosive fluids Ensure that wires and cables are adequately protected in wheel wells and other areas whe
266. pper MIL W 81381 19 200 Fluorocarbon polyimide Silver coated high strength copper alloy MIL W 81381 20 200 Fluorocarbon polyimide Nickel coated high strength copper alloy MIL W 81381 21 eo 150 Fluorocarbon polyimide Tin coated copper 11 90 11 95 RESERVED Par 11 89 Page 11 522 and 11 42 Par 11 96 9 8 98 AC 43 13 1B SECTION 8 WIRING INSTALLATION INSPECTION REQUIREMENTS GENERAL Wires and cables should be inspected for adequacy of support protection and general condition throughout The desirable and undesirable features in aircraft wiring installations are listed below and indicate conditions that may or may not exist Accordingly aircraft wiring must be visually inspected for the following requirements CAUTION For personal safety and to avoid the possibility of fire turn off all electrical power prior to starting an inspection of the aircraft electrical system or performing maintenance Wires and cables are supported by suitable clamps grommets or other devices at intervals of not more than 24 inches except when contained in troughs ducts or conduits The supporting devices should be of a suitable size and type with the wires and cables held securely in place without damage to the insulation Metal stand offs must be used to maintain clearance between wires and structure Employing tape or tubing is not acceptable as an alternative to stand offs for maintaining clearance Phenolic bl
267. r alteration and requires appropriate FAA approval The electrical load analysis must be prepared in general accordance with good engineering practices Additionally an addendum to the flight manual is generally required INSTALLATION CLEARANCE PROVISIONS All electrical equipment should be installed so that inspection and maintenance may be performed and that the installation does not interfere with other systems such as engine or flight controls WIRES WIRE BUNDLES AND CIRCUIT PROTECTIVE DEVICES Before any aircraft electrical load is increased the new total electrical load previous maximum load plus added load must be checked to determine if the design levels are being exceeded Where necessary wires wire bundles and circuit protective devices having the correct ratings should be added or replaced OUTPUT RATING The generator or alternator output ratings and limits prescribed by the manufacturer must be checked against the electrical loads that can be imposed on the affected generator or alternator by installed equipment When electrical load calculations show that the total continuous electrical load can exceed 80 percent output load limits of the generator or alternator steps must be taken to reduce the electrical load or Par 11 30 Page 11 493 increase the generating capacity of the charging system When a storage battery is part of the electrical power system the battery will be continuously charged
268. r to be used as oxygen regulators adherend one of the members being bonded together by adhesive Airworthiness Directive a regulation issued by the FAA that applies to aircraft aircraft engines propellers or appliances when unsafe condition exists and that condition is likely to exist or develop in other products of the same type design airworthy is when an aircraft or one of its component parts meets its type design and is ina condition for safe operation ambient light the visible light level measured at the surface of the part ampere A the basic unit of current flow One A is the amount of current that flows when a difference of potential of 1 V is applied to a circuit with a resistance of 1 Q One coulomb per second antenna a device designed to radiate or intercept electromagnetic waves anti tear strips strips of fabric of the same material as the airplane is covered with laid over the wing rib under the reinforcing tape apparent power the product of volts and amperes in AC circuits where the current and voltage are out of phase appliance any instrument mechanism equipment part apparatus appurtenance or accessory including communications equipment that is used or intended to be used in operating or controlling an aircraft in flight is installed in or attached to the aircraft and is not part of an airframe engine or propeller arm a measurement of distance in inches feet
269. raulic systems or stored nitrogen gas bottles that can be directed into actuating cylinders mechanical systems that can be operated manually or free fall gravity systems GENERAL INSPECTION A thorough inspection of the landing gear involves the entire structure of the gear including attachments struts wheels brakes actuating mechanisms for retractable gears gear hydraulic system and valves gear doors and all associated parts The manufacturer s inspection procedures should be followed where applicable CLEANING AND LUBRICATING It is recommended that only easily removable neutral solutions be used when cleaning landing gear components Any advantage such as speed or effectiveness gained by using cleaners containing corrosive materials can be quickly counteracted if these materials become trapped in close fitting surfaces and crevices Page 9 410 Wear points such as landing gear up and down latches jack screws door hinges pulleys cables bellcranks and all pressure type grease fittings should be lubricated after every cleaning operation To obtain proper lubrication of the main support bushings it may be necessary to jack the aircraft NOTE Any time the aircraft is on jacks check the landing gear main support bushings for wear Consult the aircraft manufacturer s overhaul manual for specific wear tolerances During winter operation excess grease may congeal and cause increased loads on the gear retract
270. rd 135 C 0 50 up High Temperature 200 C 0 50 up High Temperature 200 C 0 50 up Nuclear 135 C 0 50 up Nuclear 135 C TABLE 11 22 Plastic tie down straps MS3367 Type I Class 1 Installation Tool Tension Setting inches 1 16 5 8 Miniature MIN MS90387 1 1 16 1 Intermediate INT MS90387 1 1 16 4 Standard STD MS90387 1 3 16 8 Heavy HVY MS90387 2 The specified tool tension settings are for typical cable application Settings less than or greater than those specified may be required for special applications Cable Diameter Strap Identification Min Max MIN Select the applicable installation tool and TER TE move the tension setting to the correct NER ER TIE DOWN STRAP position See figure 11 30 S z INSTALLATION TOOL Slide tip of strap into opening in the installation tool nose piece See figure 11 30 Keeping tool against head of tie down strap ensure gripper engages tie down strap and squeeze trigger of installation tool until strap installation is completed as shown in figure 11 31 FIGURE 11 30 Tie down strap installation tool Par 11 220 Page 11 569 9 8 98 AC 43 13 1B AFTER INSTALLATION FIGURE 11 31 Completed installation TEMPORARY WIRE AND CABLE MARKING PROCEDURE A temporary wire marking procedure follows but should be used only with caution and with plans for future permanence See figure 11 32 CLEAR SLEEVE LACING TAPE SPLIT LENGTHWISE SPOT TIES WIRE
271. re also included in the sample weight and balance sheet in figure 10 18 SAMPLE WEIGHT AND BALANCE REPORT Suggested methods of tabulating the various data and computations for determining the c g both in the empty weight condition and the fully loaded condition are given in figures 10 17 and 10 18 respectively and represent a suggested means of recording this information The data presented in figure 10 17 have previously been computed in figures 10 10 and 10 11 for the extreme load conditions and figure 10 16 for equipment change and represents suggested means of recording this information Par 10 20 Page 10 476 INSTALLATION OF BALLAST Ballast is sometimes permanently installed for c g balance purposes as a result of installation or removal of equipment items and is not used to correct a nose up or nose down tendency of an aircraft It is usually located as far aft or as far forward as possible in order to bring the 9 8 98 c g position within acceptable limits with a minimum of weight increase Permanent ballast is often lead plate wrapped around and bolted to the fuselage primary structure e i tail post longerons or bulkhead members Permanent ballast invariably constitutes a concentrated load therefore the strength of the local structure and the attachment of the ballast thereto should be investigated for the design loading conditions pertinent to that particular aircraft Placard permanent ballast with Perma
272. re they may be exposed to damage from impact of rocks ice mud etc If re routing of wires or cables is not practical protective jacketing may be installed This type of installation must be held to a minimum Par 11 105 AC 43 13 1B Where practical route wires and cables above fluid lines Wires and cables routed within 6 inches of any flammable liquid fuel or oxygen line should be closely and rigidly supported A minimum of 2 inches must be maintained between wiring and such lines or related equipment except when the wiring is positively clamped to maintain at least 1 2 inch separation or when it must be connected directly to the fluid carrying equipment Ensure that a trap or drip loop is provided to prevent fluids or condensed moisture from running into wires and cables dressed downward to a connector terminal block panel or junction box Wires and cables installed in bilges and other locations where fluids may be trapped are routed as far from the lowest point as possible or otherwise provided with a moisture proof covering Separate wires from high temperature equipment such as resistors exhaust stacks heating ducts etc to prevent insulation breakdown Insulate wires that must run through hot areas with a high temperature insulation material such as fiberglass or PTFE Avoid high temperature areas when using cables having soft plastic insulation such as polyethylene because these materials are subject to dete
273. re used in most commercial transport category aircraft and are extremely fire resistant However they are not fireproof and under certain conditions they will burn The earliest generation of these fluids was developed after World War II as a result of the growing number of aircraft hydraulic brake fires which drew the collective concern of the commercial aviation industry Progressive development of these fluids occurred as result of performance requirements of newer aircraft designs The 9 8 98 airframe manufacturers dubbed these new generations of hydraulic fluid as types based their performance Today types IV and V fluids are used Two distinct classes of type IV fluids exist based on their density class I fluids are low density and class II are standard density The class I fluids provide weight savings advantages versus class II Monsanto and Exxon are the suppliers of the type IV phosphate ester based aviation hydraulic fluids In addition to the type IV fluids that are currently in use type V fluids are being developed in response to industry demands for a more thermally stable fluid at higher operating temperatures Type V fluids will be more resistant to hydrolytic and oxidative degradation at high temperature than the type IV fluids Materials of Construction Hydraulic systems require the use of special accessories that are compatible with the hydraulic fluid Appropriate seals gaskets and hoses must
274. reat variety of contacts which can include a mix of standard coaxial and large power types Coupling is accomplished by various means Smaller types are secured with screws which hold their flanges together Larger ones have integral guide pins that ensure correct alignment or jackscrews that both align and lock the connectors Rack and panel connectors use integral or rack mounted pins for alignment and box mounting hardware for couplings Module Blocks These junctions accept crimped contacts similar to those on connectors Some use internal busing to provide a variety of circuit arrangements They are useful where a number of wires are connected for 9 8 98 MS27480 MIL SPECIFICATION CLASS SHELL SIZE MS27472 WALL MOUNT RECEPTACLE MS27473 STRAIGHT PLUG MS27474 JAM NUT RECEPTACLE MS27475 HERMITIC WALL MOUNT RECEPTACLE MS27476 HERMETIC BOX MOUNT RECEPTACLE MS27477 HERMETIC JAM NUT RECEPTACLE MS27478 HERMETIC SOLDER MOUNT RECEPTACLE MS27479 WALL MOUNT RECEPTACLE NOTE 1 MS27480 STRAIGHT PLUG NOTE 1 MS27481 JAM NUT RECEPTACLE NOTE 1 MS27482 HERMETIC WALL MOUNT RECEPTACLE NOTE 1 MS27483 HERMETIC JAM NUT RECEPTACLE NOTE 1 NOTE 1 ACTIVE MS27472 MS27473 MS27474 MS27475 MS27477 MS27473 WITH MS27507 ELBOW MS27478 MS27499 MS27497 CLASS ENVIRONMENT RESISTING BOX AND THRU BULKHEAD MOUNTING TYPES ONLY SEE CLASS T POTTING INCLUDES POTTING FORM AND SHORT REAR GROMMET ENVIRONMENT RESISTING WALL AND JAM
275. relay is to be installed 11 57 11 65 RESERVED Par 11 66 9 8 98 AC 43 13 1B SECTION 5 ELECTRICAL WIRE RATING GENERAL Wires must be sized so that they have sufficient mechanical strength to allow for service conditions do not exceed allowable voltage drop levels are protected by system circuit protection devices and meet circuit current carrying requirements Mechanical Strength of Wires If it is desirable to use wire sizes smaller than 20 particular attention should be given to the mechanical strength and installation handling of these wires e g vibration flexing and termination Wire containing less than 19 strands must not be used Consideration should be given to the use of high strength alloy conductors in small gauge wires to increase mechanical strength As a general practice wires smaller than size 20 should be provided with additional clamps and be grouped with at least three other wires They should also have additional support at terminations such as connector grommets strain relief clamps shrinkable sleeving or telescoping bushings They should not be used in applications where they will be subjected to excessive vibration repeated bending or frequent disconnection from screw termination Voltage Drop in Wires The voltage drop in the main power wires from the generation source or the battery to the bus should not exceed 2 percent of the regulated voltage when the generator is carrying rat
276. res 10 5 and 10 6 Par 10 2 AC 43 13 1B BAGGAGE 60LBS ARM 60 PLUS ARM Empty Weight Center of Gravity Range The empty weight c g range is determined so that the empty weight c g limits will not be exceeded under standard specifications loading arrangements Calculations as outlined in paragraph 10 16 should be completed when it is possible to load an aircraft in a manner not covered in the Aircraft Specifications or TCDS extra tanks extra seats etc The empty weight c g range when applicable is listed in the Aircraft Specifications or TCDS Calculation of empty weight c g is shown in figures 10 5 and 10 6 Operating Center of Gravity Range The operating c g range is the distance between the forward and rearward c g limits indicated in the pertinent Aircraft Specifications or TCDS These limits are determined for the most forward and most rearward loaded c g positions at which the aircraft meets the requirements of Title 14 of the Code of Federal Regulation 14 CFR The limits are indicated in the specifications in either percent of mean aerodynamic chord MAC or inches from the Page 10 460 9 8 98 AC 43 13 1B CENTER OF GRAVITY OR POINT OF BALANCE The entire aircraft weight may be considered to be concentrated at the center of gravity Therefore the moment of the aircraft about the datum is the weight of the aircraft times the horizontal distance between the C G and the datum Example If th
277. rical tape The replacement of hydraulic units and tubing usually involves the spillage of some hydraulic fluid Care should be taken to ensure that the spillage of fluid is kept to a minimum by closing valves if available and by plugging lines immediately after they are disconnected All openings in hydraulic systems should be capped or plugged to prevent contamination of the system The importance of the proper torque applied to all nuts and fittings in a system cannot be over emphasized much torque will damage metal and seals and too little torque will result in leaks and loose parts The proper torque wrenches with the appropriate range should be used in assembling system units Disposal of Used Hydraulic Fluids In the absence of organizational guidelines the 9 8 98 technician should be guided by local state and federal regulations with regard to means of disposal of used hydraulic fluid Presently the most universally accepted procedure for disposal of phosphate ester based fluid is incineration HYDRAULIC LINES AND FITTINGS Carefully inspect all lines and fittings at regular intervals to ensure airworthiness Investigate any evidence of fluid loss or leaks Check metal lines for leaks loose anchorage scratches kinks or other damage Inspect fittings and connections for leakage looseness cracks burrs or other damage Replace or repair defective elements Make sure the lines and hoses do not chafe a
278. rioration and deformation at elevated temperatures Many coaxial cables have this type of insulation The minimum radius of bends in wire groups or bundles must not be less than 10 times the outside diameter of the largest wire or cable except that at the terminal strips where wires break out at terminations or reverse direction in a bundle Where the wire is Page 11 524 and 11 48 9 8 98 suitably supported the radius may be 3 times the diameter of the wire or cable Where it is not practical to install wiring or cables within the radius requirements the bend should be enclosed in insulating tubing The radius for thermocouple wire is 20 times the diameter Ensure that RF cables e g coaxial and triaxial are bent at a radius of no less than 6 times the outside diameter of the cable Ensure that wires and cables that are attached to assemblies where relative movement occurs such as at hinges and rotating pieces particularly doors control sticks control wheels columns and flight control surfaces are installed or protected in such a manner as to prevent deterioration of the wires and cables caused by the relative movement of the assembled parts Ensure that wires and electrical cables are separated from mechanical control cables In no instance should wire be able to come closer than 1 2 inch to such controls when light hand pressure is applied to wires or controls In cases where clearance is less than this adequate
279. rom high temperature equipment and lines to prevent deterioration of insulation Wires must be rated reference paragraph 11 66 and 11 67 so that the conductor temperature remains within the wire specification maximum when the ambient temperature and heat rise related to current carrying capacity are taken into account The residual heating effects caused by exposure to Par 11 122 Page 11 534 sunlight when aircraft are parked for extended periods should also be taken into account Wires such as in fire detection fire extinguishing fuel shutoff and fly by wire flight control systems that must operate during and after a fire must be selected from types that are qualified to provide circuit integrity after exposure to fire for a specified period Wire insulation deteriorates rapidly when subjected to high temperatures Do not use wire with soft polyethylene insulation in areas subject to high temperatures Use only wires or cables with heat resistance shielding or insulation MOVABLE CONTROLS WIRING PRECAUTIONS Clamping of wires routed near movable flight controls must be attached with steel hardware and must be spaced so that failure of a single attachment point can not result in interference with controls The minimum separation between wiring and movable controls must be at least 1 2 inch when the bundle is displaced by light hand pressure in the direction of the controls FLAMMABLE FLUIDS AND GASES An arcing fault bet
280. rther information refer to ARINC specifications such as 429 Digital Information Transfer System DATA BUS Data Buses provide the physical Mark 33 which offers simple and affordable and functional partitioning needed to enable different companies to design different answers t data communications on aircraft avionics boxes to be able to communicate information to each other It defines the 12 28 12 36 RESERVED framework for system s intergration There are several types of data bus analyzers used to Par 12 26 Page 12 609 and 12 12 9 8 98 AC 43 13 1B SECTION 3 GROUND OPERATIONAL CHECKS FOR AVIONICS EQUIPMENT NON ELECTRICAL COMPASS SWING must be performed whenever a new compass is installed The After aircraft has been parked on one heading magnetic compass can be checked for for over a year accuracy by using a compass rose located on an airport and by using a hand held master compass The check swing is normally effected by placing the aircraft on various magnetic headings and comparing the deviations with those on the deviation cards Refer to equipment or aircraft manufacture s manual A compass swing must be performed on the following occasions When the accuracy of the compass is suspected After any cockpit modification or major replacement involving ferrous metal Whenever a compass has been subjected to a shock for example after a hard landing or turbulence After aircraft has passed through a
281. rying power currents and less than 20 percent of the bundle capacity would be used Find 35 on the abscissa since there are 35 wires in the bundle and determine a derating factor of 0 52 on the ordinate from the 20 percent curve STEP 3 Derate the size 22 free air rating by multiplying 16 2 by 0 52 to get 8 4 amps in harness rating Derate the size 20 free airrating by multiplying 21 5 by 0 52 to get 11 2 amps in harness rating STEP 4 Refer to the altitude derating curve of figure 11 6 look for 60 000 feet on the abscissa since that is the altitude at which the vehicle will be operating Note that the wire must be derated by a factor of 0 79 found on the ordinate Derate the size 22 harness rating by multiplying 8 4 amps by 0 79 to get 6 6amps Derate the size 20 harness rating by multiplying 11 2 amps by 0 79 to get 8 8 amps STEP 5 To find the total harness capacity multiply the total number of size 22 wires by the derated capacity 25 x 6 6 165 0 amps and add to that the number of size 20 wires multiplied by the derated capacity 10 x 8 8 88 amps and multiply the sum by Par 11 68 AC 43 13 1B the 20 percent harness capacity factor Thus the total harness capacity is 165 0 88 0 x 0 20 50 6 amps It has been determined that the total harness current should not exceed 50 6 A size 22 wire should not carry more than 6 6 amps and size 20 wire should not carry more than 8 8 amps STEP 6 Determine
282. s mode A C and S transponders in nearby aircraft and uses the replies to identify and display potential and predicted collision threats thermocouple device to convert heat energy into electrical energy thermoplastic material a material that can repeatedly softened by an increase in the temperature and hardened by a decrease in the temperature with no accompanying chemical change For example a puddle of tar on the road in the summer during the heat of day the tar is soft and fluid however when cooler in the evening it becomes solid again thermoset material a material which becomes substantially infusible and insoluble when cured by the application of heat or by chemical means A material that will undergo or has undergone a chemical reaction different from a thermoplastics physical reaction by the action of heat catalysts ultraviolet light etc Once the plastic becomes hard additional heat will not change it back into a liquid as would be the case with a thermoplastic tip part of the torch at the end where the gas burns producing the high temperature flame transceiver a unit serving as both a receiver and a transmitter transformer a device for raising or lowering AC voltage transmitter an electronic system designed to produce modulated RF carrier waves to be radiated by an antenna also an electric device used to collect quantitative information at one point and send it to a remote indica
283. s for a part 23 aircraft is bought the mechanic would only have to reference the STC number on FAA Form 337 and the aircraft s records Part 23 appendix F would not be required If an annual inspection is to be performed on a part 23 aircraft in which a new interior was installed but the aircraft s records do not reflect that a burn test was performed on the interior s materials and fabric by an FAA Approved Repair Station or there is no mention of an STC or FAA Form 337 in the aircraft records then a burn test that meets part 23 appendix F must be accomplished before the aircraft is approved for return to service Chap 20 Sec 1 AC 43 13 1B SOURCE OF INFORMATION If information regarding the original or properly altered fire protection qualities of certain cabin interior materials is not available requests for this information should be made to the aircraft manufacturer or the local FAA regional office specifying the model aircraft and the aircraft manufacturer The date the aircraft was manufactured or the serial number and the 14 CFR part under which the aircraft is operated i e CAR 3 14 CFR part 91 or part 121 etc UPHOLSTERY AND OR BELTS Upholstery and or belts that have been washed may lose some or all of their fire resistant qualities Unless the soap is completely removed from the cloth the strength of the material may be significantly reduced Consult the manufacturer to determine how to maintain th
284. s must be installed in a manner which ensures that moisture and fluids will drain out of and not into the connector when unmated Wiring must be routed so that moisture accumulated on the bundle will drain away from connectors When connectors must be mounted in a vertical position as through a shelf or floor the connectors must be potted or environmentally sealed In this situation it is better to have the receptacle faced downward so that it will be less susceptible to collecting moisture when unmated Wire Support A rear accessory backshell must be used on connectors that are not enclosed Connectors having very small size wiring or are subject to frequent maintenance activity or located in high vibration areas must be provided with a strain relief type backshell The wire bundle should be protected from mechanical damage with suitable cushion material where it is secured by the clamp Connectors that are potted or have molded rear adapters do not normally use a 9 8 98 separate strain relief accessory Strain relief clamps should not impart tension on wires between the clamp and contact Slack Sufficient wire length must be provided at connectors to ensure a proper drip loop and that there is no strain on termination after a complete replacement of the connector and its contacts Identification Each connector should have a reference identification that is legible throughout the expected life of the aircraft FEED THROUGH BUL
285. scoloration and loose rivets Inspect the tip for cracks by grasping it with the hand and slightly twisting about the longitudinal blade centerline and by slightly bending the tip backward and forward If the leading edge and the cap have separated carefully inspect for cracks at this point Cracks usually start at the leading edge of the blade A fine line appearing in the fabric or plastic may indicate a crack in the wood Check the trailing edge of the propeller blades for bonding separation or damage Examine the wood close to the metal sleeve of wood blades for cracks extending outward on the blade These cracks sometimes Par 8 91 remove sludge Page 8 403 from propeller and correct least once a occur at the threaded ends of the lag screws and may be an indication of internal cracking of the wood Check the tightness of the lag screws which attach the metal sleeve to the wood blade in accordance with the manufacturer s instructions Inspect and protect the shank areas of composition blades next to the metal sleeve in the same manner as that used for wood blades METAL PROPELLERS AND BLADES These propellers and blades are generally susceptible to fatigue failure resulting from the concentration of stresses at the bottoms of sharp nicks cuts and scratches It is necessary therefore to frequently and carefully inspect them for such injuries Propeller manufacturers publish SB s and instructions which prescrib
286. se fluids polyalphaolefin base and phosphate ester base fluids When servicing a hydraulic system the technician must be certain to use the correct category of replacement fluid Hydraulic fluids are not necessarily compatible For example contamination of the fire resistant fluid MIL H 83282 with MIL H 5606 may render the MIL H 83282 non fire resistant Mineral Base Fluids MIL H 5606 mineral oil based hydraulic fluid is the oldest dating back to the 1940 s It is used in many systems especially where the fire hazard is comparatively low MIL H 6083 is simply a rust inhibited version of MIL H 5606 They completely interchangeable Suppliers generally ship hydraulic components with MIL H 6083 Par 9 25 Page 9 423 Polyalphaolefin Based Fluids MIL H 83282 is a fire resistant hydrogenated polyalphaolefin based fluid developed in the 1960 s to overcome the flammability characteristics of MIL H 5606 MIL H 83282 is significantly more flame resistant than MIL H 5606 but a disadvantage is the high viscosity at low temperature It is generally limited to 40 F However it can be used in the same system and with the same seals gaskets and hoses as MIL H 5606 MIL H 46170 is the rust inhibited version of MIL H 83282 Small aircraft predominantly use MIL H 5606 but some have switched to MIL H 83282 if they can accommodate the high viscosity at low temperature Phosphate Ester Based Fluid Skydrol Hyjet These fluids a
287. se it with clear water To sterilize swab the mask thoroughly with a gauze or sponge soaked in a water merthiolate solution This solution should contain 1 5 teaspoon of merthiolate per 1 quart of water Wipe the mask with a clean cloth and air dry Replace the hose if it shows evidence of deterioration Hoses may be cleaned in the same manner as the mask Observe that each mask breathing tube end is free of nicks and that the tube end will slip into the cabin oxygen receptacle with ease and not leak 9 8 98 FUNCTIONAL TESTING AFTER REPAIR Following repair and before inspection plates cover plates or upholstering are replaced test the entire system Open the cylinder valve slowly and observe the pressure gauge on a high pressure system A pressure of approximately 1 800 psi at 70 F should be indicated on the gauge Cylinder pressure will vary considerably with radical temperature changes Check the system by installing one of the mask hose fittings minus the mask in each of the cabin wall outlets to determine whether there is a flow If a demand mask is used check by breathing through the mask and if appropriate clean the mask according to paragraph 9 49d Check the complete system for leaks in accordance with the procedure outlined in paragraph 9 49b 2 d If leaks are found close the cylinder valve and open an outlet to reduce the pressure in the system to zero The following checks may be made
288. severe electrical storm After lighting strike Whenever a change is made to the electrical system Whenever a change of cargo is likely to affect the compass When an aircraft operation is changed to a different geographic location e g Miami Florida to Fairbanks Alaska with a major change in magnetic deviation Par 12 37 Page 12 610 9 8 98 When flux valves are replaced Compass Swing Procedures The magnetic compass must be checked for accuracy in a location free of steel structures underground pipes or cables or equipment that produces magnetic fields The master compass is a reverse reading compass with a gun sight arrangement mounted on top of it With the aircraft facing North and the person in the cockpit running the engine s at 1000rpm a mechanic standing approximately 30 feet in front of the aircraft facing South shoots or aligns the master compass with the aircraft center line Using hand signals the mechanic signals the person in the cockpit to make additional adjustments to align the aircraft with the master compass Once aligned on the heading the person in the cockpit runs the engine s to approximately 1 700 rpm duplicate the aircraft s magnetic field and then the person reads the compass NOTE For conventional gear aircraft the mechanic will have to position the magnetic compass in the straight and level position or mount the tail of the aircraft on a moveable dolly to simulate a s
289. sistance has not been significantly increased by the loosening of connections or corrosion Wire Size Wires must have sufficient mechanical strength to allow for service conditions Do not exceed allowable voltage drop levels Ensure that the wires are protected by system circuit protection devices and that they meet circuit current carrying requirements If it is desirable to use wire sizes smaller than 20 particular attention should be given to the mechanical strength and installation handling of these wires e g vibration flexing and termination When used in interconnecting airframe application 24 gauge wire must be made of high strength alloy Installation Precautions for Small Wires As a general practice wires smaller than size 20 must be provided with additional clamps grouped with at least three other wires and have additional support at terminations such as connector grommets strain relief clamps shrinkable sleeving or telescoping bushings They should not be used in applications where they will be subjected to excessive vibration repeated bending or frequent disconnection from screw terminations Identification All wire used on aircraft must have its type identification imprinted along its length It is common practice to follow this part number with the five digit letter C A G E code identifying the wire manufacturer Existing installed wire that Page 11 517 needs replacement can thereby be identified as
290. skis If skis that permit attachment to the wheels and tires are used maintain proper tire pressure as under inflated tires may push off the wheels if appreciable side loads are developed in landing or taxiing Repair of Ski Runners Repair limits are found in the applicable manufacturer s manual Fractured wooden ski runners usually require replacement If a split at the rear end of the runner does not exceed 10 percent of the ski length it may be repaired by attaching one or more wooden crosspieces across the top of the runner using glue and bolts Bent or torn metal runners may be straightened if minor bending has taken place and minor tears may 9 8 98 be repaired in accordance with procedures recommended in Chapter 4 Metal Structure Welding and Brazing Ski Pedestals Tubular Pedestals Damaged pedestals made of steel tubing may be repaired by using tube splices as shown in the chapter on welding Cast Pedestals Consult a Federal Aviation Administration FAA representative on the repair of cast pedestals TYPES OF LANDING GEAR PROBLEMS During inspection and before removing any accumulated dirt closely observe the area being inspected while the wingtips are gently rocked up and down Excessive motion between normally close fitting landing gear components may indicate wear cracks or improper adjustment If a crack exists it will generally be indicated by dirt or metallic particles which tend to outline the fault
291. ssible damage in accordance with the propeller manufacturer s prescribed procedures and if necessary repaired according to the manufacturer s instructions If the propeller is damaged beyond the repair limits established by the propeller manufacturer and a replacement is necessary install the same make model approved or alternate as specified in the equipment list applicable FAA Aircraft Specification Type Certificate Data Sheet TCDS or Supplemental Type Certificate STC A sample manufacturer s propeller inspection checklist is shown in table 8 2 It shows the items to be inspected and the inspection intervals WOOD OR COMPOSITION PROPELLERS AND BLADES Wood propellers are usually found on low power reciprocating engines while composition Carbon fiber Kevlar propellers are used on high horsepower reciprocating and turbine engines Due to the nature of wood these propellers should be inspected frequently to assure airworthiness Inspect for defects such as cracks dents warpage glue failure delamination defects in the finish and charring of the wood between the propeller and the flange due to loose propeller mounting bolts Composition propellers should be inspected in accordance with the propeller manufacturer s instructions Par 8 91 Page 8 402 Fixed pitch propellers are normally removed from the engine at engine overhaul periods Whenever the propeller is removed visually inspect the rear surface for any indica
292. support must be provided to prevent chafing Ensure that wires and cables are provided with enough slack to meet the following requirements Permit ease of maintenance Prevent mechanical strain on cables junctions and supports the wires Permit free movement of shock and vibration mounted equipment Par 11 96 Page 11 525 AC 43 13 1B Allow shifting of equipment as necessary to perform alignment servicing tuning removal of dust covers and changing of internal components while installed in aircraft Ensure that unused wires are individually dead ended tied into a bundle and secured to a permanent structure Each wire should have strands cut even with the insulation and a pre insulated closed end connector or a inch piece of insulating tubing placed over the wire with its end folded back and tied Ensure that all wires and cables are identified properly at intervals of not more than 15 inches Coaxial cables are identified at both equipment ends WIRING REPLACEMENT Wiring must be replaced with equivalent wire see paragraph 11 78 when found to have any of the following defects Wiring that has been subjected to chafing or fraying that has been severely damaged or that primary insulation is suspected of being penetrated Wiring on which the outer insulation is brittle to the point that slight flexing causes it to crack Wiring having weather cracked outer insulation Wiring that is known to have b
293. t Apply cement to the surface as outlined in OUTSIDE PATCHES sub paragraph 9 42b 1 a e Roll thoroughly with a roller to ensure that all air pockets are removed and a firm bond is secured Allow to dry and apply talc over the seam as previously outlined Allow to cure for at least 60 hours before performing leak tests and storing LIFE PRESERVERS Inflatable life preservers are subject to general deterioration due to aging Experience has indicated that such equipment may be in need of replacement at the end of 5 years due to porosity of the rubber coated material Wear of such equipment is accelerated when stowed on board aircraft because of vibration which causes chafing of the rubberized fabric This ultimately results in localized leakage Leakage is also likely to occur where the fabric is folded because sharp corners are formed When these corners are in contact with the carrying cases or with adjacent parts of the rubberized fabric they tend to wear through due to vibration NOTE The surface under the patch should be as smooth as possible so that the torn edge of the fabric may be attached to the patch instead of attempting to attach the patch to the fabric Scatter the handful of talc that was placed inside the tube by grasping the sides of the flotation tube and pulling them apart Par 9 42 Page 9 445 9 8 98 Life preservers should be inspected in accordance with the manufacturer s specificat
294. t 10 percent Tubing that has been formed and cut to final length should be deburred to prevent wire insulation damage When installing replacement tube sections with fittings at both ends care should be taken to eliminate mechanical strain TABLE 11 23 Bend radii for rigid conduit Nominal Tube O D Minimum Bend Radii inches inches Par 11 253 9 8 98 FLEXIBLE CONDUIT Flexible aluminum conduit conforming to Specification MIL C 6136 is available in two types Type Bare Flexible Conduit and Type II Rubber Covered Flexible Conduit Flexible brass conduit conforming to Specification MIL C 7931 is available and normally used instead of flexible aluminum where necessary to minimize radio interference Also available is a plastic flexible tubing Reference MIL T 8191A Flexible conduit may be used where it is impractical to use rigid conduit such as areas that have motion between conduit ends or where complex bends are necessary The use of transparent adhesive tape is recommended when cutting flexible tubing with a hacksaw to minimize fraying of the braid The tape should be centered over the cutting reference mark with the saw Page 11 583 AC 43 13 1B cutting through the tape After cutting the flexible conduit the transparent tape should be removed the frayed braid ends trimmed burrs removed from inside the conduit and coupling nut and ferrule installed Minimum acceptable bending radii for flexible condu
295. t be made after a maintenance action on a transponder Refer to Title 14 of the Code of Federal Regulations 14 CFR part 91 sections 91 411 and 91 413 Inspection of the emergency locator transmitter operation condition and date of the battery Perform a function check of the radio by transmitting a request for a radio check Perform a function check on navigation equipment by moving the omni bearing selection OBS and noting the needle swing and the TO FROM flag movement 9 8 98 COMMUNICATION SYSTEMS Ground operation of communication systems in aircraft may be accomplished in accordance with the procedures appropriate for the airport and area in which the test is made and the manufacturer s manuals and procedures Check system s for side tone clarity of transmission squelch operations using head phones speaker s and hand microphone Ifa receiver or transmitter is found to be defective it should be removed from the aircraft and repaired VHF OMNI DIRECTIONAL RANGE VOR VOR operates within the 108 0to 117 9 MHz frequency band The display usually consists of a deviation indicator and a TO FROM indicator The controls consist of a frequency selector for selecting the ground station and an OBS which is used for course selection An ON OFF flag is used to determine adequate field strength and presence of a valid signal There are numerous configurations when integrated into flight directors and or when using a sla
296. t of an aircraft includes all operating equipment that has a fixed location and is actually installed in the aircraft It includes the weight of the airframe powerplant required equipment optional and special equipment fixed ballast full engine coolant hydraulic fluid Page 10 458 residual fuel and oil Additional information regarding fluids that may be contained in the aircraft systems and must be included in the empty weight will be indicated in the pertinent Aircraft Specifications or TCDS Useful Load The useful load is the empty weight subtracted from the maximum weight of the aircraft This load consists of the pilot crew if applicable maximum oil fuel passengers and baggage unless otherwise noted Weight Check The weight check consists of checking the sum of the weights of all items of useful load against the authorized useful load maximum weight less empty weight of the aircraft Datum The datum is an imaginary vertical plane from which all horizontal measurements are taken for balance purposes with the aircraft in level flight attitude The datum is indicated in most Aircraft Specifications or TCDS On some of the older aircraft when the datum is not indicated any convenient datum may be selected Once the datum is selected all moment arms and the location of the permissible c g range must be taken with reference to it Examples of typical locations of the datum are shown in figure 10 1 Arm or Moment
297. t of present generation navigation systems This space based navigation system is based on a 24 satellite system and is highly accurate within 100 meters for establishing position The system is unaffected by weather and provides a world wide common grid reference system Database updating and antenna maintenance are of primary concern to the GPS user NOTE Aircraft must be outside of hangar for ground test of GPS AUTOPILOT SYSTEMS Automatic Flight Control Systems AFCS are the most efficient managers of aircraft performance and control There are three kinds of autopilot two axes three axes and three axes Par 12 16 Page 12 605 AC 43 13 1B with coupled approach capability Attention must be given to the disconnect switch operation aural and visual alerts of automatic and intentional autopilot disconnects override forces and mode annunciation servo operation rigging and bridle cable tension and condition In all cases the manufacturer s inspection and maintenance instructions must be followed ALTIMETERS Aircraft conducting operations in controlled airspace under instrument flight rule IFR are required to have their static system s and each altimeter instrument inspected and tested within the previous 24 calendar months Frequent functional checks of all altimeters and automatic pressure altitude reporting systems are recommended Examine the altimeter face for evidence of needle scrapes or other damage
298. tain the proper algebraic sign or through all balance computations For the sake of uniformity these computations visualize the aircraft with the nose to the left In this position any arm to the left forward of the datum is minus and any arm to the right rearward of the datum is plus Any item of weight added to the aircraft either side of the datum is plus weight any weight item removed is a minus weight When multiplying weights by arms the answer is plus if the signs are the same and minus if the signs are different The following combinations are possible Items added forward of the datum weight x arm moment Items added to the rear of the datum weight x arm moment Items removed forward of the datum weight x arm moment Items removed rear of the datum weight x arm moment The total weight of the airplane is equal to the weight of the empty aircraft plus the weight of the items added minus the weight of the items removed The total moment of the aircraft is the algebraic sum of the empty weight moment of the aircraft and all of the individual moments of the items added and or removed Par 10 16 Page 10 469 AC 43 13 1B WEIGHT AND BALANCE EXTREME CONDITIONS The weight and balance extreme conditions represent the maximum forward and rearward c g position for the aircraft Include the weight and balance data informat
299. tain their durability UV cure inks are cured in line much like dot matrix Ink jet marks the wire on the fly and makes a reasonably durable and legible mark without damaging the insulation Ink jets normally mark wire from 0 030 to 0 25 inch outside diameter Multiconductor cable can also be marked LASER MARKING Of the variety of laser marking machines UV lasers are proving to be the best This method marks into the surface of the wire s insulation without degradation to its performance One common type of UV laser is referred to as an excimer laser marker UV laser produces the most durable marks because it marks into the insulation instead of on the surface However excimer laser will only mark insulation that contain appropriate percentages of titanium dioxide TiO2 The wire can be marked on the fly UV can mark from 0 030 to 0 25 inch outside diameter The UV laser makes only gray marks and they appear more legible on white or pastel colored insulation IDENTIFICATION SLEEVES Flexible sleeving either clear or opaque is satisfactory for general use When color coded or striped component wire is used as part of a cable the identification sleeve should specify which color is associated with each wire identification code Identification sleeves are normally used for identifying the following types of wire or cable Unjacketed shielded wire Thermocouple wire identification is normally accomplished by means of identifica
300. tate of charge and mechanical integrity Age To determine the life and age of the battery record the install date of the battery on the battery During normal battery maintenance battery age must be documented either in the aircraft maintenance log or in the shop maintenance log State of Health Lead acid battery state of health may be determined by duration of service interval in the case of vented batteries by environmental factors such as excessive heat or cold and by observed electrolyte leakage as evidenced by corrosion of Par 11 15 Page 11 487 AC 43 13 1B wiring and connectors or accumulation of powdered salts If the battery needs to be refilled often with no evidence of external leakage this may indicate a poor state of the battery the battery charging system or an over charge condition Use a hydrometer to determine the specific gravity of the battery electrolyte which is the weight of the electrolyte compared to the weight of pure water Take care to ensure the electrolyte is returned to the cell from which it was extracted When a specific gravity difference of 0 050 or more exists between cells of a battery the battery is approaching the end of its useful life and replacement should be considered Electrolyte level may be adjusted by the addition of distilled water State of Charge Battery state of charge will be determined by the cumulative effect of charging and discharging the battery I
301. ted Steel Steel Steel Plated Steel Steel Corrosion Corrosion Resisting Cadmium Plated Corrosion Resisting Cadmium Resisting Steel or Cadmium Steel Steel Plated Steel Plated Steel Avoid connecting copper to magnesium Use washers having a conductive finished treated to prevent corrosion suggest AN960JD10L Par 11 191 Page 11 558 9 8 98 AC 43 13 1B CAD PL STEEL AN 735 CLAMP COPPER TERMINAL ALUMINUM CYLINDRICAL WASHERS SURFACE CAD PL STEEL LOCKWASHER CAD PL STEEL LOCKNUT FIGURE 11 20 Copper jumper connector to tubular structure CAD PL STEEL SCREW ALUMINUM P di WASHER STRUCTURE A M MM ALUMINUM ALUMINUM ALLOY WASHER OR CORROSION RESISTING STEEL CAD PL STEEL CONDUIT LOCKWASHER CAD PL STEEL LOCKNUT FIGURE 11 21 Bonding conduit to structure CAD PL STEEL SCREW AN 735 CLAMP ALUMINUM WASHER BARE ALUMINUM TERMINAL CYLINDRICAL A SURF ACE uon ya CAD PL STEEL LOCKWASHER FIGURE 11 22 Aluminum jumper connection to tubular structure Par 11 190 Page 11 559 9 8 98 FUEL SYSTEMS Small metallic objects within an aircraft fuel tank that are not part of the tank structure should be electrically bonded to the structure so as to dissipate static charges that may otherwise accumulate on these objects A practical bonding design would use a flexible braided jumper wire or riveted bracket In such situations a DC resistance of 1 ohm or less should
302. the aircraft is operated at its cruise speed See figure 12 1 Vacuum Pump Systems In order to overcome the major drawback of the venturi tube that is its susceptibility to ice aircraft were equipped with engine driven vacuum pumps and the gyro instruments were driven by air pulled through the instrument by the suction produced by these pumps A suction relief valve maintained the desired pressure usually about four inches of mercury on the attitude gyro instruments and a needle valve between one of the attitude indicators and the turn and slip indicator restricted the airflow to maintain the desired 2 inches of suction in its case Most of the early instruments used only paper filters in each of the instrument cases but in some installations a central air filter was used to remove contaminants from the cabin air before it entered the instrument case The early vacuum pumps were vane type pumps of what is called the wet Page 12 612 9 8 98 TWO INCH VENTURI TURN AND SLIP INDICATOR AC 43 13 1B FOUR INCH VENTURI ENTRAL AIR FILTER SUCTION DIRECTIONAL GYRO FIGURE 12 1 Venturi system for providing airflow through gyro instruments type one with a cast iron housing and steel vanes Engine oil was metered into the pump to provide sealing lubrication and cooling and then this oil along with the air was blown through an oil separator where the oil collected on baffles and was returned to the engine cra
303. the tube with 5 or 10 psi and let the air out to re seat the tube Install the valve core and fill the tire to the recommended pressure SLIPPAGE To reduce the possibility of tire and tube failure due to slippage and to provide a means of detecting tire slippage tires should be marked and indexed with the wheel rim Paint a mark one inch wide and two inches long across the tire side wall and wheel rim Use a permanent type paint in a contrasting color such as white red or orange Pre flight inspection must include a check of slippage marks for alignment If the Par 9 25 Page 9 421 9 8 98 AC 43 13 1B slippage marks are not in alignment a detailed inspection must be made the reason determined and if necessary the condition corrected before the next flight NOTE Mechanics should be aware that retread tires can be diametrically bigger than a new tire While this does not pose a problem on fixed landing gear aircraft it may pose a problem on retractable gear aircraft Due to a 5 to 8 percent expansion of the tire caused by the ambient temperature if a retread tire is installed on a retractable gear aircraft it is strongly recommended that a retraction test be performed This is to ensure the tire will not become wedged in the wheel well during take off and landing operation 9 20 9 24 RESERVED Par 9 25 Page 9 422 9 8 98 AC 43 13 1B SECTION 2 HYDRAULIC SYSTEMS GENERAL Hydraulic systems in aircraft provide a
304. their cooling properties 9 8 98 Static power converters often emit unacceptable levels of EMI that may disrupt communication equipment and navigation instruments Properly shielded connectors terminal blocks and wires may be required with all shields well grounded to the air frame CAUTION Do not load converters beyond their rated capacity ACCEPTABLE MEANS OF CONTROLLING OR MONITORING THE ELECTRICAL LOAD The use of placards is recommended to inform the pilot and or crew members of the combination s of loads that may be connected to each power source Installation of warning lights can be installed that will be triggered if the battery bus voltage drops below 13 volts on a 14 volt system or 26 volts on a 28 volt system For installations where the ammeter is in the battery lead and the regulator system limits the maximum current that the generator or alternator can deliver a voltmeter can be installed on the system bus As long as the ammeter never reads discharge except for short intermittent loads such as operating the gear and flaps and the voltmeter remains at system voltage the generator or alternator will not be overloaded In installations where the ammeter is in the generator or alternator lead and the regulator system does not limit the maximum current that the generator or alternator can deliver the ammeter can be redlined at 100 percent of the generator or alternator rating If the ammeter read
305. thods A or B in figure 8 29 or by use of aircraft standard bolts 1 16 inch larger than the original bolts Make the repairs in accordance with the recommendations of the propeller metal hub manufacturer or the engine manufacturer as applicable Obtain from the engine or propeller hub manufacturer suitable flange bushings with threaded or smooth bores as illustrated in methods A or B of figure 8 29 Drill the flange and insert the bushings as recommended by the propeller to accommodate the bushings and protect the holes with 2 coats of aluminum paint or other high moisture resistant coating Use bolts of the same size as those originally used Any of the following combinations may be used Par 8 74 Page 8 399 1 drilled head bolt and castellated nut 2 drilled head bolt and threaded bushing or 3 undrilled bolt and self locking nut Where it is desirable to use oversized bolts obtain suitable aircraft standard bolts 1 16 inch larger than the original bolts Enlarge the crankshaft propeller flange holes and the propeller hub holes sufficiently to accommodate the new bolts without more than 0 005 inch clearance Such reboring will be permitted only once Further repairs of bolt holes may be in accordance with the methods listed in A or B of figure 8 29 NOTE Method A or B is preferred over the oversized bolt method because a propeller hub flange re drilled in accordance with this latter 9 8 98 AC 43 13 1B
306. tion flare forming tool for the size of tubing and type of fitting A double flare is used on soft aluminum tubing 3 8 inch outside diameter and under and a single flare on all other tubing In making the connections use hydraulic fluid as a lubricant and then tighten Over tightening will damage the tube or fitting which may cause a failure Under tightening may cause leakage which could result in a system failure CAUTION Mistaken use of 45 degree automotive flare forming tools may result in improper tubing flare shape and angle causing misfit stress and strain and probable system failure Repair of Metal Tube Lines Minor dents and scratches in tubing may be repaired Scratches or nicks not deeper than 10 percent of the wall thickness in aluminum alloy tubing that are not in the heel of a bend may be repaired by burnishing with hand tools Replace lines with severe die marks seams or splits in the tube Any crack or deformity in a flare is unacceptable and cause for rejection A dent less than 10 percent of the tube diameter is not objectionable unless it is in the heel of a bend A severely damaged line should be replaced however it may be repaired by cutting out the damaged section and inserting a tube section of the same size and material Flare both ends of the undamaged and replacement tube sections and make the connection by using standard unions sleeves and tube nuts If the damaged portion is short enough omit the i
307. tion of cracks When any defects are found disassemble the metal hub from the propeller Inspect the hub bolts for wear and cracks at the head and threads and if cracked or worn replace with new equivalent bolts Inspect for elongated bolt holes enlarged hub bore and for cracks inside the bore or anywhere on the propeller Repair propellers found with any of these defects If no defects are found the propeller may be reinstalled on the engine Before installation touch up with varnish all places where the finish is worn thin scratched or nicked Track and balance the propeller and coat the hub bore and bolt holes with some moisture preventive such as asphalt varnish In case the hub flange is integral with the crankshaft of the engine final track the propeller after it is installed on the engine In all cases where a separate metal hub is used make a final balance and track with the hub installed on the propeller On new fixed pitch propeller installations inspect the bolts for proper torque after the first flight and after the first 25 hours of flying Thereafter inspect and check the bolts for proper torque at least every 50 hours No definite time interval can be specified since a bolt s proper torque is affected by changes in the wood caused by the moisture content of the air where the airplane is flown and stored During wet weather some moisture is apt to enter the propeller wood through the holes drilled in the hub The wo
308. tion sleeves As the thermocouple wire is usually of the duplex type two insulated wires within the same casing each wire at the termination point bears the full name of the conductor Thermocouple conductors are alumel Page 11 565 9 8 98 chromel iron constantan and copper constantan Coaxial cable should not be hot stamped directly When marking coaxial cable care should be taken not to deform the cable as this may change the electrical characteristics of the cable When cables cannot be printed directly they should be identified by printing the identification code and individual wire color where applicable on a nonmetallic material placed externally to the outer covering at the terminating end and at each junction or pressure bulkhead Cables not enclosed in conduit or a common jacket should be identified with printed sleeves at each end and at intervals not longer than 3 feet Individual wires within a cable should be identified within 3 inches from their termination Multiconductor cable normally use identification sleeves for identifying unshielded unjacketed cable High temperature wire with insulation is difficult to mark such as Teflon and fiberglass IDENTIFICATION TAPE Identification tape can be used in place of sleeving in most cases i e polyvinylfluoride OPERATING CONDITIONS For sleeving exposed to high temperatures over 400 F materials such as silicone fiberglass should be used INSTALL
309. tioned so that moisture will drain out of them when unmated Wires exiting connectors must be routed so that moisture drains away from them Page 11 527 9 8 98 JUNCTION BOXES PANELS SHIELDS AND MICROSWITCH HOUSINGS Examine housing assemblies to ascertain the following Verify that one or more suitable holes about 3 8 inch diameter but not less than 1 8 inch diameter are provided at the lowest point of the box except vapor tight boxes to allow for drainage with the aircraft on the ground or in level flight Verify that vapor tight or explosion proof boxes are externally labeled VAPOR TIGHT or EXPLOSION PROOF Verify that boxes are securely mounted Verify that boxes are clean internally and free of foreign objects Verify that safety wiring is installed on all lid fasteners on J boxes panels shields or microswitch housings which are installed in areas not accessible for inspection in flight unless the fasteners incorporate self locking devices Verify that box wiring is properly aligned Verify that there are no unplugged unused holes except drainage holes in boxes CONDUIT RIGID METALLIC FLEXIBLE METALLIC AND RIGID NONMETALLIC Inspection of conduit assemblies should ascertain that Conduit is relieved of strain and flexing of ferrules Conduit is not collapsed or flattened from excessive bending Par 11 99 Page 11 528 AC 43 13 1B Conduits will not trap fluids or condensed moisture Su
310. tip until strap is snug around cable Page 11 567 9 8 98 AC 43 13 1B TIEDOWN STRAP FIGURE 11 29 Tie down strap installation BEFORE INSTALLATION FIGURE 11 28 Cable markers TABLE 11 18 Selection table for standard sleeves Wire or Cable Markable Installed Installed As supplied Diameter Range Length Sleeve Wall Inside inches Length nom Thickness Diameter Min Max i max inches min inches Based on 12 characters per inch TABLE 11 19 Selection table for thin wall sleeves Wire or Cable Markable Installed Installed Wall As supplied Diameter Range Length Sleeve Thickness Inside inches inches Length nom max inches Diameter Min Max inches min inches 0 085 0 080 0 075 0 110 0 100 0 150 0 135 0 225 Based on 12 characters per inch Par 11 218 Page 11 568 9 8 98 AC 43 13 1B TABLE 11 20 Selection table for high temperature sleeves Wire or Cable Markable Installed Installed As supplied Diameter Range Length Sleeve Wall Inside inches Length Thickness Diameter min Min Max inches nom max inches inches inches Based on 12 characters per inch TABLE 11 21 Selection table for cable markers Cable Diameter Type of Cable Marker Number of Number Marker Range Attachment of Lines Thickness inches Holes of Type nom inches 0 25 0 50 Standard 135 C 0 25 0 50 High Temperature 200 C 0 25 0 50 Nuclear 135 C 0 50 up Standard 135 C 0 50 up Standa
311. tive loads and motor loads and must be replaced with identical make and model switches Proximity Switches These switches are usually solid state devices that detect the presence of a predetermined target without physical contact and are usually rated 0 5 amps or less Switch Rating The nominal current rating of the conventional aircraft switch is usually stamped on the switch housing and represents the continuous current rating with the contacts closed Switches should be derated from their nominal current rating for the following types of circuits Circuits containing incandescent lamps can draw an initial current that is 15 times greater than the continuous current Contact burning or welding may occur when the switch is closed Inductive circuits have magnetic energy stored in solenoid or relay coils that is released when the control switch is opened and may appear as an arc Direct current motors will draw several times their rated current during starting and magnetic energy stored in their 9 8 98 armature and field coils is released when the control switch is opened Switch Selection Switches for aircraft use should be selected with extreme caution The contact ratings should be adequate for all load conditions and applicable voltages at both sea level and the operational altitude Consideration should be given to the variation in the electrical power characteristics using MIL STD 704 as a guide Derating Fact
312. tly since it is more susceptible to personnel abuse than a permanently installed system INSPECTION Hands clothing and tools must be free of oil grease and dirt when working with oxygen equipment Traces of these organic materials near compressed oxygen may result in spontaneous combustion explosions and or fire Oxygen Tanks and Cylinders Inspect the entire exterior surface of the cylinder for indication of abuse dents bulges and strap chafing Examine the neck of cylinder for cracks distortion or damaged threads 9 8 98 Check the cylinder to determine if the markings are legible Check the date of the last hydrostatic test If the periodic retest date is past do not return the cylinder to service until the test has been accomplished Inspect the cylinder mounting bracket bracket hold down bolts and cylinder holding straps for cracks deformation cleanliness and security of attachment In the immediate area where the cylinder is stored or secured check for evidence of any types of interference chafing deformation or deterioration Lines and Fittings Inspect oxygen lines for chafing corrosion flat spots and irregularities i e sharp bends kinks and inadequate security Check fittings for corrosion around the threaded area where lines joined Pressurize the system and check for leaks See paragraph 9 49b 2 d CAUTION In pressurizing the system actuate the valve slowly to
313. to its performance capabilities and the inadvertent use of a lower performance and unsuitable replacement wire avoided In addition to the type identification imprinted by the original wire manufacturer aircraft wire also contains its unique circuit identification coding that is put on at the time of harness assembly The traditional Hot Stamp method has not been totally satisfactory in recent years when used on modern ultra thin walled installations Fracture of the insulation wall and penetration to the conductor of these materials by the stamping dies have occurred Later in service when these openings have been wetted by various fluids serious arcing and surface tracking have damaged wire bundles Extreme care must be taken during circuit identification by a hot stamp machine on wire with a 10 mil wall or thinner Alternative identification methods such as Laser Printing and Ink Jet are coming into increasing use by the industry When such modern equipment is not available the use of stamped identification sleeving should be considered on thin walled wire especially when insulation wall thickness falls below 10 mils AIRCRAFT WIRE MATERIALS Only wire specifically designed for airborne use must be installed in aircraft Authentic Aircraft Wire Most aircraft wire designs are to specifications that require manufacturers to pass rigorous testing of wires before being added to a Qualified Products List QP
314. tor electrically transponder an airborne receiver transmitter designed to aid air traffic control personnel in tracking aircraft during flight unbonding adhesive or cohesive failure between laminates Compare definitions of adhesive cohesive debond and disbond AC 43 13 1B Appendix 1 very high frequency VHF a frequency between 30 and 300 MHz VHF omnirange electronic air navigation system that provides accurate direction information in relation to a certain ground station videoscope a type of borescope visible light electromagnetic radiation that has a wavelength in the range from about 3 900 to 7 700 angstroms and that may be seen by the unaided human eye visual check utilizing acceptable methods techniques and practices to determine physical condition and safety item volt unit of potential potential difference or electrical pressure voltage regulator device used in connection with generators to keep the voltage constant as load or speed is changed warp threads in a fabric that run the length of the woven material as it comes from the mill watt ihe unit of power equal to a joule per second wattmeter an instrument for measuring electrical power waveguide a hollow typically rectangular metallic tube designed to carry electromagnetic energy at extremely high frequencies wavy grained wood wood in which the fibers collectively take the form of wav
315. tors installed in pressurized areas with Teflon sealing plugs or rods Installation of spare contacts is optional except for future wiring addition requirements See paragraph 11 234 9 8 98 AC 43 13 1B TABLE 11 25 Contact cavity sealing quick reference Connector Installation Types Unpressurized Area Firewall Non Firewall fee ee Teflon Sealing Rods No Yes Stub Wires Note 2 Yes Spare Contacts NOTE 1 Sealing plugs may be included with the spare connector and may be used for sealing unused contacts Sealing rods are procured from stock by the foot See table 11 26 for sealing rod dimensions NOTE 2 Stub wires must be of the same type as the other wires of the bundle HIGH TEMP LACING CORD DIMENSIONS ARE IN INCHES 1 8 FIGURE 11 39 Stub wire installation TABLE 11 26 Sealing rod dimensions CONTACT SIZE DIAMETER ROD LENGTH INCHES AWG INCHES MIN MAX MAX 1 16 5 8 3 32 7 8 1 8 78 SEALING PLUG OR ROD BACK OF CONNECTOR SPARE CONTACT INSTALLED UNWIRED SPARE CONTACT FIGURE 11 40 Sealing unused contact cavities unpressurized areas cut away view 11 264 11 270 RESERVED Par 11 271 Page 11 585 9 8 98 AC 43 13 1B SECTION 20 ELECTRICAL AND ELECTRONIC SYMBOLS GENERAL The electrical and electronic SYMBOLS Only those symbols associated symbols shown here are those that are likely with aircraft electrical and electronic wiring to be encountered by the av
316. traight and level cruise configuration If the aircraft compass is not in alignment with the magnetic North with the master compass then the mechanic can correct the error by making small adjustments to the North South brass adjustment screw with a nonmetallic screw driver This screw driver can be made out of brass stock or stainless steel welding rod The aircraft should be positioned facing South and aligned with the Par 12 37 Page 12 611 AC 43 13 1B 9 8 98 master compass Using the same procedures correct any error in the compass reading using the check for errors on the East West heading using the same procedures for the North South check except the corrections should be made using the East West correction brass screw Check the compass reading on all cardinal headings Record the last reading and prepare a compass correction card The maximum deviation plus or minus is 10 degrees on any one heading If the compass cannot be adjusted to meet the requirements install another one NOTE A common error that affects the compass s accuracy is the mounting of a compass on or in the instrument panel using steel machine screws nuts rather than brass hardware If the aircraft has an electrical system it is recommended that two complete compass checks be performed one with minimum electrical equipment operating and the other with all electrical accessories on e g radios navigation radar and lights If the co
317. tructure rather than through other bonded parts Bonds must be installed to ensure that the structure and equipment are electrically stable and free from the hazards of lightning static discharge electrical shock etc To EQUIPMENT SURFACE 28VDC SOURCE o AC 43 13 1B ensure proper operation and suppression of radio interference from hazards electrical bonding of equipment must conform to the manufacturer s specifications Use of bonding testers is strongly recommended Measurements should be performed after the grounding and bonding mechanical connections are complete to determine if the measured resistance values meet the basic requirements A high quality test instrument AN AN USM 21A or equivalent is required to accurately measure the very low resistance values specified in this document Another method of measurement is the millivolt drop test as shown in figure 11 19 Use appropriate washers when bonding aluminum or copper to dissimilar metallic structures so that any corrosion that may occur will be on the washer AIRCRAFT STRUCTURE SURFACE Adjust R1 rheostat for 10 amperes on ammeter Record the millivolt reading Example Millivolt reading is 30 MVS 30 MVS 10 AMPS Figure 11 19 Millivolt drop test Par 11 186 3 MILLIOHMS RESISTANCE Page 11 554 9 8 98 BONDING JUMPER INSTALLATIONS Bonding jumpers should be made as short as practicable and installed in such a manner that the res
318. ucture must provide adequate conductivity to 9 8 98 accommodate normal and fault currents of the system without creating excessive voltage drop or damage to the structure At least three fasteners located in a triangular or rectangular pattern must be used to secure such brackets in order to minimize susceptibility to loosening under vibration If the structure is fabricated of a material such as carbon fiber composite CFC which has a higher resistivity than aluminum or copper it will be necessary to provide an alternative ground path s for power return current Current Return Paths for Internally Grounded Equipment Power return or fault current ground connections within flammable vapor areas must be avoided If they must be made make sure these connections will not arc spark or overheat under all possible current flow or mechanical failure conditions including induced lightning currents Criteria for inspection and maintenance to ensure continued airworthiness throughout the expected life of the aircraft should be established Power return fault currents are normally the highest currents flowing in a structure These can be the full generator current capacity If full generator fault current flows through a localized region of the carbon fiber structure major heating and failure can occur CFC and other similar low resistive materials must not be used in power return paths Additional voltage drops in the return path can cause
319. ue links the actual time of switch closing or opening can be checked by removing all air from the strut and then collapsing the strut In every case the adjustment should be such that the gear control cannot be placed in the UP position or that the system cannot operate until the shock strut is at the full extended position EMERGENCY SYSTEMS Exercise emergency landing gear systems periodically to ensure proper operation and to prevent inactivity dirt and corrosion from rendering the system inoperative when needed Most emergency systems employ either mechanical pressure bottle or free fall extension capabilities Check for the proper safeties on triggering mechanisms and for the presence of required placards and necessary accessories such as cranks levers handles etc Emergency blow down bottles should be checked for corrosion damage and then weighed to see if the bottle is still retaining the charge 9 8 98 LANDING GEAR COMPONENTS The following items are susceptible to difficulties and should be inspected service Shock Absorbers Inspect the entire shock strut for evidence of leaks cracks and possible bottoming of the piston as this condition causes overloading of landing gear components and contributes to fatigue cracks Check all bolts bolt holes pins and bushings for condition lubrication and proper torque values Grease fitting holes pressure type are especially vulnerable to cracks and cross threadi
320. ule as follows GALLONS OF FUEL NUMBER OF PASSENGERS POUNDS OF BAGGAGE 100 Only two passengers are listed to prevent the maximum weight of 2100 Ibs from being exceeded FIGURE 10 12 Loading conditions determination of the number of passengers and baggage permissible with full fuel Par 10 20 Page 10 473 9 8 98 AC 43 13 1B EXAMPLE OF THE DETERMINATION OF THE POUNDS OF FUEL AND BAGGAGE PERMISSIBLE WITH MAXIMUM PASSENGERS po Weight xAm Moment Do 6 aw Baggage pere T Baggage 2100 38466 Divide the TM total moment by the TW total weight to obtain the loaded center of gravity TM 38466 18 6 TW 2100 The above computations show that with the maximum number of passengers 39 gallons of fuel and zero pounds of baggage may be carried in this aircraft without exceeding either the maximum weight or the approved C G range This condition may be entered in the loading schedule as follows GALLONS OF FUEL NUMBER OF PASSENGERS POUNDS OF BAGGAGE 2 Conditions as entered from Figure 10 12 F Front seat R Rear seat FIGURE 10 13 Loading conditions determination of the fuel and baggage permissible with maximum passengers Par 10 20 Page 10 474 9 8 98 AC 43 13 1B EXAMPLE OF THE DETERMINATION OF THE FUEL AND THE NUMBER AND LOCATION OF PASSENGERS PERMISSIBLE WITH MAXIMUM BAGGAGE Weih Am O Moment H o
321. upplemental Type Certificate SW switch SYM GEN symbol generator T R transformer rectifier TA T 4rue air temperature TBDP tie bus differential protection TC Type Certificate TCAS traffic alert and collision avoidance system TCDS Type Certificate Data Sheets Structural Inspection AC 43 13 1B Appendix 2 TDC top dead center TFR transfer TIG tungsten inert gas TMC thrust management computer TMS terminal marking sleeve TMS thrust management system TMSP thrust mode select panel TRU transformer rectifier unit TSO Technical Standard Order TXPDR transponder u micro UBR atility bus relay F underfrequency HF ultrahigh frequency 300 MHz to 3 GHz NDF underfrequency NDV undervoltage S underspeed SB us Uupper sideband SEC nicroseconds V uundervoltage UV utraviolet V ac Vac or VAC volts alternating current V dc Vdc or VDC volts direct current V volts voltage vertical valve VA volt amperes VAR volt ampere reactive VFR visual flight rules VHF vhf very high frequency 30 TO 300 MHz VLSIvery large scale integration VOR VHF omnirange visual omnirange VORTAC VOR tactical air navigation VR voltage regulator VRMS volts root means square W watts WARN warning WCP weather radar control panel WEA weather WEU warning electronics unit power supply WPT waypoint WX WXR weather radar XCVR transceiver XDCR transducer XFMR tra
322. urface and the reflector lanyard for defective conditions and security of attachment Emergency Rations Check the food ration cans for obvious damage severe dents and an expiration date Replace items when severely damaged dented or when the date is expired Ensure that the opening key is attached Par 9 49 Page 9 439 AC 43 13 1B Tarpaulins Spread out and check for tears mildew corroded grommets and general condition Fishing Kit Check for damaged container or for tampering Replace if damaged or incomplete Raft Knife Check for corrosion and ease of opening and security of the knife lanyard to the raft Compass condition Check for proper operation and Protective Ointment Sunburn Check the sunburn ointment containers for cracks or crushed condition Install the ointment in a 6 inch mailing tube and tape the ends to prevent crushing Stow it where it will be subjected to the least amount of pressure in the kit Oars Check for serviceability Wrap the oars separately in craft paper and seal with tape Stencil inspected in letters not less than 1 2 inch high on each package Emergency Water Containers Check for open seams holes etc Replace defective containers Repair Kit Check for proper wrapping and missing items Four plugs are wrapped in a single container This container and the pliers are wrapped in waterproof paper and sealed 9 8 98 AC 43 13 1B with waterproof tape Th
323. usable type a replacement hose may be 9 8 98 fabricated as described in figure 9 8 When a hose assembly is removed the ends should be tied as shown in figure 9 11 so that the preformed shape will be maintained Refer to figure 9 10 for minimum bend radii All flexible hose installations should be supported at least every 24 inches Closer supports are preferred They should be carefully routed and securely clamped to avoid abrasion kinking or excessive flexing Excessive flexing may cause weakening of the hose or loosening at the fittings O Ring Seals An understanding of O ring seal applications is necessary to determine when replacement should be made The simplest application is where the O ring merely serves as a gasket when it is compressed within a recessed area by applying pressure with a packing nut or screw cap Leakage is not normally acceptable in this type of installation In other installations the O ring seals depend primarily upon their resiliency to accomplish their sealing action When moving parts are involved minor seepage may be normal and acceptable A moist surface found on moving parts of hydraulic units is an indication the seal is being properly lubricated When systems are static seepage past the seals is not normally acceptable Par 9 30 Page 9 430 AC 43 13 1B During inspection consider the following to determine whether seal replacement is necessary How much fluid is permitted to seep
324. use a cleaner recommended by manufacturers of oxygen equipment Replace lines and fittings that cannot be cleaned The high pressure lines which are located between the oxygen bottle outside the oxygen service filler and the regulator are normally fabricated from stainless steel or thick wall seamless copper alloy tubing The fittings on high pressure lines are normally silver brazed NOTE Use silver alloys free of cadmium when silver brazing The use of silver brazing alloys which contain cadmium will emit a poisonous gas when heated to a molten state This gas is extremely hazardous to health if inhaled 9 8 98 The low pressure lines extend from the pressure regulator to each passenger and crew oxygen outlet These lines are fabricated from seamless aluminum alloy copper or flexible hose Normally flare or flange type connections are used CAUTION Do not allow oil grease flammable solvent or other combustibles such as lint or dust to come in contact with threads or any parts that will be exposed to pressurized oxygen It is advisable to purge the oxygen system any time work has been accomplished on any of the lines and fittings Use dry nitrogen or dry air for purging the system All open lines should capped immediately after purging When oxygen is being lost from a system through leakage a sequence of steps may be necessary to locate the opening Leakage may often be detected by listening for the
325. using soapy water In order to eliminate pressure variations due to temperature differences at the time the initial and final reading are taken test the raft in a room where the temperature is fairly constant If the pressure drop is satisfactory the raft should be considered as being in an airworthy condition and returned to service after being fitted with correctly charged CO bottles as determined by weighing them Rafts more than 5 years old are likely to be unairworthy due to deterioration It is suggested that serviceable rafts be marked to indicate the date of inspection and that soapstone be used when folding them preparatory to insertion into the carrying case Take care to see that all of the raft s required equipment is on board and properly stowed If the raft lanyard used to prevent the raft from floating away from the airplane is in need of 9 8 98 replacement use a lanyard not less than 20 feet long and having a breaking strength of about 75 pounds It is recommended that the aforementioned procedure be repeated every 18 months using the CO bottle s for inflation If a single bottle is used for inflating both compartments it should be noted whether the inflation is proceeding equally to both compartments Occasionally the formation of carbon dioxide snow may occur in one passage of the distribution manifold and divert a larger volume of gas to one compartment which may burst if the mattress valve is not open to r
326. ust not revert to liquid or become gummy or sticky due to high humidity or contact with chemical fluids Potting compounds meeting Specification MIL S 8516 are prepared in ready to use tube type dispensers and in the unmixed state consisting of the base compound and an accelerator packed in paired containers To obtain the proper results it is important that the manufacturer s instructions be closely followed Potting compounds normally cure at temperatures of 70 F to 76 F If the mixed compound is not used at once the working pot life normally 90 minutes can be prolonged by storing in a deep freeze at 20 F for a maximum of 36 hours The time factor starts from the instant the accelerator is added to the base compound and includes the time expended during the mixing and application processes Mixed compounds that are not to be used immediately should be cooled and thawed quickly to avoid wasting the short working life Chilled compounds should be thawed by blowing compressed air over the outside of the container Normally the compound will be ready for use in 5 to 10 minutes CAUTION Do not use heat or blow compressed air into the container when restoring the compound to the working temperature POTTING CONNECTORS Connectors that have been potted primarily offer protection against concentration of Page 11 579 and 11 96 9 8 98 moisture in the connectors A secondary benefit of potting is the reduced possibility
327. ve The following checks and inspections should be completed Check for abrasions chafing and soiling across folded cell areas and around metal parts Condemn the life preserver when unsuitable conditions are found Par 9 43 Page 9 446 AC 43 13 1B Check for separation of cell fabric and loose attachments along the edges of patches and sealing tapes Repair if practicable Check for deterioration in areas where oil and grease are noted Condemn deteriorated cells If deterioration is not noted clean the areas with mild soap and water and rinse with clear water Inspect the snaps and or buckles to ensure proper operation Inspect the instruction panel for readability Inspect all stitching for gaps pulls and tears Visually inspect the cell containers for snags cuts loose stitching and oil and grease spots Repair or replace as necessary Inspect the hardware for rusted or broken parts and cotter pins for damage Ensure that pins are smooth and free of burrs Check the inflator discharge lever for proper operation Move the inflator discharge lever slowly through a normal cycle of operation to ensure freedom of operation and to make certain that the piercing pin has sufficient movement to discharge the cylinder The point of the pin should move past the surface of the gasket in the inflator In the unoperated position the end point should be slightly below the gasket surface Check the installation of th
328. ved compass system which uses an additional indicator that points continually to the selected omni station regardless of OBS selection In order to determine the accuracy specified in a functional check a ground test set must be used in accordance with the manufacturer s specifications For the purpose of this inspection maintenance activity the following operational check can be accomplished to determine if the equipment has the accuracy required for operation in instrument flight rules environment Verify audio identification OBS operation flag operation radio magnetic indicator RMI interface and applicable navigation NAV switching functions The operational check is also published in the AIM section 1 1 4 This check is required by 14 CFR part 91 section 91 171 before instrument flight operations Par 12 10 Page 12 603 AC 43 13 1B DISTANCE MEASURING EQUIP MENT DME The operation of DME consists of paired pulses at a specific spacing sent out from the aircraft this is what is called interrogation and are received by the ground station which then responds with paired pulses at the specific spacing sent by the aircraft but at a different frequency The aircraft unit measures the time it takes to transmit and then receive the signal which then is translated into distance DME operates on frequencies from 962 MHz to 1213 MHz Because of the curvature of earth this line of sight signal is reliable up to 1
329. vice relay GSSR ground service select relay GSTR ground service transfer relay GTAW eas tungsten arc welding GWPC ground proximity warning computer H L Ahigh low HEA high frequency radio antenna HF hf high frequency 3 to 30 MHz HFCP high frequency radio control panel HI Z high impedance HZ hertz F F F F G G G G G G 9 8 98 I D inner diameter 1 O input output IAPS integrated avionics processor system IAS indicated airspeed IDG integrated drive generator IF intermediate frequency IFR instrument flight rules IGN ignition IIS integrated instrument system ILS 3 nstrument landing system INDL indicator light INST anstrument INSTR instrument INTCON interconnect INTEC ainterface INTER interrogation INTPH interphone INV nverter IR ILS teceiver kHz kilohertz KSI thousands of pounds per square inch kV kilovolts kVA kilovoltamperes kVAR kKilovoltampere reactive L Band tadio frequency band 390 to 1550 MHz LCD iiquid crystal display LD Joad LED iight emitting diode LF If low frequency 30 to 300 kHz LO Z low impedance LOC ocalizer LRU line replaceable unit LS loudspeaker LSB lower sideband LSPTM iimit switch position transmitter module LT iight LTS lights MAC nmean aerodynamic chord MAN ELEC 3nanual electric MBA marker beacon antenna MCDP aumaintenance control a
330. ween an electrical wire and a metallic flammable fluid line may puncture the line and result in a fire Every effort must be made to avoid this hazard by physical separation of the wire from lines and equipment containing oxygen oil fuel hydraulic fluid or alcohol Wiring must be routed above these lines and equipment with a minimum separation of 6 inches or more whenever possible When such an arrangement is not practicable wiring must be routed so that it does not run parallel to the fluid lines A minimum of 2 inches must be maintained between wiring and such lines and equipment except when the wiring is positively clamped to maintain at least 1 2 inch separation or when it must be connected 9 8 98 AC 43 13 1B directly to the fluid carrying equipment Install clamps as shown in figure 11 10 These clamps should not be used as a means of supporting the wire bundle Additional clamps should be installed to support the wire bundle and the clamps fastened to the same structure used to support the fluid line s to prevent relative motion FIGURE 11 10 Separation of wires from plumbing lines 11 127 11 134 RESERVED Par 11 135 Page 11 535 Par 11 135 9 8 98 AC 43 13 1B SECTION 10 SERVICE LOOP HARNESSES Plastic Tie Strips GENERAL The primary function of a service loop harness is to provide ease of maintenance The components mounted in the instrument panel and on the lower console and other equipment that must
331. ween front and rear seats 2 Main wheel weighing point is located FORWARD 3 AFT of datum Actual measured distance from the main weight point centerline to the tail or nose point centerline 222 Oil over and above ZERO tank reading a _ Gals _ Lbs c In ACTUAL EMPTY WEIGHT Scale Reading Net Weight 5 Right 54 o 564 6 Let Tooo o 5 0 55 J Boere MEN NMNQ MEME ee CENTER OF GRAVITY AS WEIGHED 10 relative to main wheel weighing point a Tail wheel airc Item 3 222 x Item 7 40 Item 9 1169 b Nose wheel airc Item 3 x Item 8 Item 9 11 relative to datum a Tail wheel airc Item 10 7 6 addedto Item 2 3 b Nose wheel airc Item 10b addedto Item2 COMPUTE IF AIRCRAFT WITH OIL Item 4 x X Am Moment T o I mL Less Oil 4b 4c EmpyToas X 5 J Empty weight C G REPAIR AGENCY FIGURE 10 17 Sample weight and balance report to determine empty weight center of gravity Par 10 22 Page 10 478 9 8 98 AC 43 13 1B EQUIPMENT LIST Required or Optional Item Numbers as Shown in Aircraft Specification 105 106 303 401 a Ap s oe ee Special Equipment Item Arm 105 EA Enter above those items included in the empty weight WEIGHT AND BALANCE EXTREME CONDITIONS Approved fwd limit 8 5 Approved max weight
332. with the other recommendations mentioned for retractable landing gear systems Sheet metal floats should be repaired using approved practices however the seams Par 9 10 Page 9 416 AC 43 13 1B between sections of sheet metal should be waterproofed with suitable fabric and sealing compound A float that has undergone hull repairs should be tested by filling it with water and allowing it to stand for at least 24 hours to see if any leaks develop Skis and Ski Installation Skis should be inspected for general condition of the skis cables bungees and fuselage attachments If retractable skis are used checks in accordance with the general practices for retractable gear should be followed Ski manufacturers usually furnish acceptable repair procedures It is advisable to examine ski installations frequently to keep them maintained in airworthy condition If shock cord is used to keep the ski runner in proper trim periodically examine to ensure that the cord has enough elasticity to keep the runner in its required attitude and the cord is not becoming loose or badly frayed Replace old or weak shock cords When other means of restraint are provided examine for excessive wear and binding and replace or repair as required Examine the points of cable attachment both on the ski and the aircraft structure for bent lugs due to excessive loads that have been imposed while taxiing over rugged terrain or by trying to break loose frozen
333. xtent practicable These steps can reduce an aircraft s susceptibility to incidents that might result from connector failures Adjacent Locations Mating of adjacent connectors should not be possible In order to ensure this adjacent connector pairs must be different in shell size coupling means insert arrangement or keying arrangement When such means are impractical wires should be routed and clamped so that incorrectly mated pairs cannot reach each other Reliance on markings or color stripes is not recommended as they are likely to deteriorate with age Par 11 233 Page 11 578 AC 43 13 1B Sealing Connectors must be of a type that exclude moisture entry through the use of peripheral and interfacial seal that are compressed when the connector is mated Moisture entry through the rear of the connector must be avoided by correctly matching the wire s outside diameter with the connector s rear grommet sealing range It is recommended that no more than one wire be terminated in any crimp style contact The use of heat shrinkable tubing to build up the wire diameter or the application of potting to the wire entry area as additional means of providing a rear compatibility with the rear grommet is recommended These extra means have inherent penalties and should be considered only where other means cannot be used Unwired spare contacts should have a correctly sized plastic plug installed See section 19 Drainage Connector
334. zing points State of Charge SOC for sealed Specific Freeze point lead acid batteries at 70 Gravity C F SOC 12 volt 24 volt 1 300 70 95 100 12 9 25 8 1 275 62 80 75 12 7 25 4 1 250 52 62 50 12 4 24 8 1 225 37 35 25 12 0 24 0 1 200 26 16 1 175 20 4 1 150 15 5 1 125 10 13 1 100 8 19 TEMPERATURE CORRECTION U S manufactured lead acid batteries are considered fully charged when the specific gravity reading is between 1 275 and 1 300 A 1 3 discharged battery reads about 1 240 and a 2 3 discharged battery will show a specific gravity reading of about 1 200 when tested by a hydrometer and the electrolyte temperature is 80 F However to determine precise specific gravity readings a temperature correction see table 11 2 should be applied to the 9 8 98 hydrometer indication As an example a hydrometer reading of 1 260 and the temperature of the electrolyte at 40 F the corrected specific gravity reading of the electrolyte is 1 244 TABLE 11 2 Sulfuric acid temperature correction Electrolyte Temperature Points to be subtracted or added to specific gravity readings BATTERY MAINTENANCE Battery inspection and maintenance procedures vary with the type of chemical technology and the type of physical construction Always follow the battery manufacturer s approved procedures Battery performance at any time in a given application will depend upon the battery s age state of health s

AC 43.13-1B - Basco Group, LLC

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