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1. PA24 180 SN 24 1 to 24 1676 PA24 180 SN 24 1684 andup 9 16 Pa24 250 oe With the barrel held in this position adjust the rod end to allow the attaching bolt to slide into place In order to check and set rudder travel disconnect the rudder cables at the rudder bellcrank Insert a small round dowel into the rear curved corned of the rudder skin extending down sufficiently towards the elevator skin Measure outwards each side of the fuselage center line a distance of 6 1 8 and make 2 small dots approx 6 apart each side on the elevator skin top surface Run two pieces of masking tape outboard of these dots parallel with the fuselage center line Move the rudder left and right and adjust the stops so that the pointer travels no further than the inside edge of the previously installed masking tape You now have the correct 25 degrees travel angle The elevator must be held in the level position to conduct this check Reconnect the rudder cables and adjust their length to position the rudder pointer on the center line and readjust cable tension On those aircraft with interconnected controls adjust the coordinator springs to 1 16 extension with the rudder and ailerons in the neutral position If you have done this correctly your aircraft is in proper ground to flight rigging In the previous article stressed the fact that the nose wheel travel should not exceed the prescribed amounts which are controlled by the installed travel stops
2. NOTE It must be recognized that the three items above are of critical importance to the successful and proper operation of the nose landing gear system Further careful ground handling practices i e during parking etc must be followed to avoid damage to now landing gear components as specified in Items 1 and 2 above 3 Perform a minimum of two 2 gear retraction cycles one with rudder pedals completely depressed full left and another with rudder pedals completely depressed full right During gear cycling observe that the aligner roller is engaged within the gear aligner guide bracket channel reference attached sketch for a pictorial description a Ifthe aligner roller does not engage within the aligner guide bracket during gear cycling as specified above it will be necessary to readjust the nose gear steering travel limits 4 Apply steering limit markings on the nose gear strut housing as denoted on attached sketch ICS TIPS Chapter 7 Landing Gear and Brakes Page 53 of 103 Note Apply steering linut markings red paint on the strut assem Nose Gear Aligner Roller bly as shown N Aligner Guide Bracket Paint SO Above and 38 Below Grease Fitting Housing Assembly E Strut Collar Service Letter No 575 ICS TIPS Chapter 7 Landing Gear and Brakes Page 54 of 103 GEAR CRACKED HOUSING Main Undercarriage Housing Cracks originate from this hole in web propogating from hole inwards and outward
3. Serious damage is incurred if these distances are exceeded At the recent San Diego Convention observed your Comanches being towed with a unit which did not have a turntable fitted which left you at the mercy and intelligence of the operator not to exceed the steering limits If these limits are exceeded several things can happen Firstly the bolts holding the nose gear steering arm can shear off Secondly the bolt holding the pulley cluster in the floor below the pilot s feet can bend and release cable tension Thirdly the rudder stops will contact and if exceeded far enough the bellcrank will crack or break off Having observed this operation conducted a walk around of the airport parking area and inspected each Comanche for broken steering lock stops Of the 95 aircraft only 14 still had the stops in place Only 2 in the Flagship area had their stops intact One twin and one single had taken the precaution of disconnecting and flagging the nose wheel torque links This is a serious problem because once the stops are gone who knows when and by how much the limits have been exceeded in later towings ICS TIPS Chapter 7 Landing Gear and Brakes Page 58 of 103 BRAKES 180 250 wanted to pass on some information concerning old style Comanche brakes These are listed in the Comanche Parts Manual as Cleveland P N 3000 250 and are normally installed on PA 24 s serial 24 1 through 24 3295 They can be identified visually by
4. Usually there are three although some have only two You should be able to put your fingers on them unerringly even in the dark 2 I hear of quite simple things as items getting left on the floor behind the telescopic handle and a frequent one is your Jeppesen manual When you select up and the handle gets to the manual or whatever you left there as a blocking device it will stop and the 30 amp circuit breaker will kick out If this happens to you select down on the gear switch Put the circuit breaker back in When the gear goes down it will release the blocking object Put whatever it is somewhere else Then put the gear back up 3 After take off and you have the gear up and are out of the traffic pattern check the gear up light to determine that the gear went all the way up If it did not most likely the circuit breaker went out just before the gear finished its up travel If you don t check this when you put the gear down nothing is going to happen until you reset the circuit breaker This is far too common an occurrence due to improper or lack of maintenance on the gear ICS TIPS Chapter 7 Landing Gear and Brakes Page 61 of 103 4 For aircraft with the telescopic handle there are three things to tell you if the gear is down In order of importance they are the green light the horn and lastly the position of the red knob on the handle Note where this sits in the normal position For the other aircraft there are two methods th
5. reached down to extend the gear and it only extended about half way After raising the gear and extending it to the same result a couple of times realized that was going to have to manually extend the gear The next day the shop found that the worm gear had cracked completely and was binding when the gear was extended The complete gearbox was shipped to Bob Weber by UPS to be rebuilt figured that it made sense to rebuild the whole box rather than just replace the gear If the worm drive had gone bad who knows what would be next Within a couple of days Bob had rebuilt the box and returned it After installation we swung the gear a number of times and it was smooth as silk Here is the rub The satisfying clunk as the gear swung home was gone What had interpreted as locking into place was probably the worm gear binding So if you have an older Comanche with the Johnson Bar recommended checking it occasionally actually recommend checking it every time you extend the gear If it isn t silky smooth you may have a problem and would recommend a trip to your A amp P to check it ICS TIPS Chapter 7 Landing Gear and Brakes Page 48 of 103 BRAKE LINING FOR STAINLESS STEEL DISCS purchased my Twin Comanche last May and immediately started having brake problems As it turned out had metallic brakes on the left side and non metallic on the right was getting about 25 landings out of the metallics and hundreds out of the non met
6. using my homemade jacks ICS TIPS Chapter 7 Landing Gear and Brakes Page 86 of 103 Several years ago had my first encounter with AD 77 13 21 the one that requires a gear inspection every 1000 hours and a change of bungee cords every 500 hours or three years had just read an article in the Comanche Flyer that told about making a tool for the bungee change and being an avid do it yourselfer became intrigued with the idea of making my own tool and trying the bungee changing procedure myself built the tool and learned from an old pro at my airport about how to stretch the bungee cord for positioning on the tool it s described in Tips Special Then with the blessing of my IA using a set of borrowed jacks and following the procedure prescribed in the maintenance manual did the bungee change myself It was a real accomplishment thought and quite satisfying to learn how it could be done plus got to know my airplane more intimately Then the jacks went back to their owner and knew would again have to locate a set and beg to borrow them for next year s annual It would be so convenient to have my own but knew they were costly at least in those days The idea of having my own jacks became almost an obsession Then one day was in a tool store and saw some long stroke hydraulic jacks that looked like ones I d seen in advertisements for aircraft jacks The price of the ones in the store was reasonable they looked lik
7. Now 10 yrs later vs the originals lasting 10 yrs am going through replacement again Also this represents replacement at 1 2 the flight hours Why In automotive after market items tend to last longer than OEM The answer comes in a couple of things that ICS owners may want to note for the future First any machinist will tell you when installing precision fit bushings bearings that to press fit the holder you must restore bore size by reaming To get the precision bore fit this cannot be done freehand with a hand drill without some sort of custom alignment jig It should be done in a shop with a machine and everything aligned and clamped true Few A amp Ps have this capability unfortunately So the end result tends to be a NEW bushing bearing with slop rivaling the removed one On my AJC the bearings did at home with lathe and or drill press are still good Those done at the airport on the A C are shot So this time they are all being done by alignment jigs Those that practicality requires on site reaming will be done with jigs made to provide reamer alignment found another reason for the bearings wearing out prematurely that failed to notice the first time Some of the parts with bearing inserts are equipped with grease fittings The inserts were press fitted but not drilled to let the grease into the bearing area Hence greasing is not doing any good and may do harm The latter by encouraging the bearing to slip in t
8. We can and should do better It is nearly entirely within our possibilities and reach to reduce this gear accident rate to nearly zero Appendix Here are some pertinent quotes from Part 830 para 830 2 Aircraft accident means an occurrence associated with the operation of an aircraft which takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked and in which any person suffers death or serious injury or in which the aircraft receives substantial damage Incident means an occurrence other than an accident associated with the operation of an aircraft which affects or could affect the safety of operations Substantial damage means damage or failure which adversely affects the structural strength performance or flight characteristics of the aircraft and which would normally require major repair or replacement of the affected component Engine failure or damage limited to an engine if only one engine fails or is damaged bent fairings or cowling dented skin small punctured holes in the skin or fabric ground damage to rotor or propeller blades and damage to landing gear wheels tires flaps engine accessories brakes or wingtips are not considered substantial damage for the purpose of this part R amp R A HOW I DID IT ARTICLE Glen Plymate ICS 02658 For some R amp R means Rest and Recreation But for my Comanche R amp R means Raise and Retract
9. a dental pick or the like and twist and pull it until it is seated 8 Puta washer over the clevis Cut the fishing line loop and carefully insert a cotter key The washer needs to be thick enough to insure that the clevis remains seated and doesn t work backward into the tube 9 Now put the transmission and motor back into the plane Hook them up and cycle the gear ICS TIPS Chapter 7 Landing Gear and Brakes Page 66 of 103 realize the last part of this procedure sounds far fetched but it can be done and will be glad to answer questions about the method and if you really need some help put the whole thing in a box and send it to me and I ll put it back together for you UNDER CARRIAGE PROBLEMS WITH PA 30 J M Bisco ICS 08662 Not long ago had a problem with G AVPS selected down on the under carriage The nose wheel was half down and the circuit breaker popped out and the motor was hot tried to disconnect the red lever on the undercarriage emergency The weight of the undercarriage was holding the red lever in place and could not disconnect it tried the circuit breaker after 5 minutes and still no motor had two choices to turn the rubber motor drive to up or down for under carriage The up seemed less hassle With one finger turned the motor drive rubber until the under carriage up lights came on It was now possible to disconnect the red lever and use the emergency system to lock the under carriage down Thus
10. an out of adjustment situation in the Landing Gear Retraction System Transmission Assembly This overloaded the motor and kicked out the breaker After resetting and kicking the breaker again decided to use the emergency extension system remembered clearly how easy it had been to get the gear down and locked A real thorough check pilot who knew everything about Comanches had demonstrated the system to me twice and each time he raised the gear in the air with the emergency extension lever and locked the release lever back on the actuating screw to return the system to electric operation Thankful that had been so well checked out put the gear switch in the down position took off the cover flipped the release lever up allowing the gear to fall a little further down put the emergency extension lever in the extension socket and ICS TIPS Chapter 7 Landing Gear and Brakes Page 27 of 103 pushed forward to complete the cycle and lock the gear down The assembly moved forward a small amount and the release lever jammed solidly under the torque tube You may say without fear of contradiction from that moment forward 16Y had my full and undivided attention No amount of coaxing would move the gear more than an inch or so The system was simply jammed tried every remedy could imagine was pushing on the extension lever with both feet and pulling the airplane up at the same time Gradually the pull ups got sharper the pushing and grunt
11. and bushing wear tolerances to be checked every 1000 hours and replaced if necessary In addition it requires the bungee cords to be replaced every three years or 500 hours whichever comes first Part of this AD added the second assist spring to the nose gear On C models and PA 39 s there is an additional locking bar in the emergency gear well that does lock the gear down once it has been extended by the emergency procedure Always minimize side loads on the gear and especially if it has been extended by the emergency procedure Always pursue all avenues to get the gear to extend normally prior to using the emergency procedures You can by exerting force on the handle aid the motor in lowering the gear if it tends to overload and pop the gear motor circuit breaker Be sure to allow the breaker to cool prior to resetting and trying to help the motor have used this procedure twice to lower the gear after it would pop the breaker when we selected gear down during training flights This happened because the gear motor was on its last legs and in dire need of an overhaul ICS TIPS Chapter 7 Landing Gear and Brakes Page 74 of 103 have also run into situations where if we lowered the gear at 140 MPH or so the gear motor circuit breaker would pop But if we slowed to 110 MPH the gear would lower normally If your gear won t lower after slowing to 150 MPH get it fixed something is wrong so don t wait for a more serious situation to de
12. and lower the gear as was done on some of the Mooney airplanes The air oil oleo struts on each gear provide the necessary shock absorbing capabilities necessary to minimize the landing loads on the main spar The struts should be maintained at the proper shiny strut spacing which is two and three quarters of an inch on most Comanches The airplane should have a full static load i e full fuel but no baggage or passengers when this measurement is taken Twin hint leave the nose strut a little low 1 4 1 2 inch You don t land on the nose do you And leaving the mains 1 4 to 1 2 inch higher will in conjunction with the small nose tire STC allow the twin to remain on the runway until VMC is reached We talk about the gear being locked down however there are no locks per se as there are on many other airplanes The gear is held down by the over center adjustments of the drag links which allows the weight of the airplane to insure the gear stays down In addition the push pull cables attached to the drive system add some force to insure the gear stays down When the gear is extended by the emergency means i e raising the motor release arm only the over center adjustments with some help from the bungee cords and assist springs on the main gear and two assist springs on the nose gear insure that the gear stays extended while taxiing over expansion joints or cracks in the pavement In light of this we have the gear AD that requires bolts
13. and packed with new grease The actuator motor was a different story had purchased a spare a year ago with the intention of installing when needed and thereby avoid the delay at Piper dealer The old motor was ready to fall The brushes were 70 percent worn carbon soot and particles coated everything the armature was worn but worse were the wires holding the brushes Because they were so worn the wires had to stretch to their limit but in the process they contacted the rotating armature which chewed them off was down to a few strands Maybe 10 to 25 cycles and it would have quit dead The new motor installed just fine Just remember to disconnect and connect only one wire at a time If your aircraft has more than 1 500 hours on it recommend that you invest in a spare actuator motor about 47 This is really cheap insurance and is not difficult to install at all Note that you will have to jack up the aircraft and cycle the gear after this exercise to check everything out Especially the limit switches If you have the time install a sensitive ammeter to check load during extension and retraction or if you do not then an accurate stopwatch will also reveal possible binding or other problems Extension should be about 5 seconds and retraction 6 seconds BRAKE CYLINDER MAINTENANCE Saturday morning at Springbank field just outside of Calgary Canada and the day was bright and clear but cold In fact it was the first real cold snap of
14. and resetting the transmission and she was again just like a bought one TOE BRAKES Q As a new member of ICS am sure would enjoy the society and my Comanche better if had toe brakes Our local mechanic knows of no conversion kit or STC Do you sure hope so A An STC for PA 24 series was awarded to Atlas Aviation Inc 8505 Montview Blvd Denver CO Its number is SA891WE GEAR TRANSMISSION LOOSE MOTOR A member wrote of an incident with his 250 On an attempted landing the gear jammed one half way out Finally they were able to manually extend it Examination revealed that the gear transmission motor assembly had broken loose from its mounts and allowed the assembly to ride on the jack screw in the compartment below the floor The bulkhead is the one at the rear of the compartment viewable through the Man Emergency extension opening and the channel goes from the rear of this bulkhead to the next bulkhead aft ICS TIPS Chapter 7 Landing Gear and Brakes Page 12 of 103 hence is NOT viewable The channel has lightening holes on both sides which leave only narrow side strips of aluminum sheet to carry the load In my opinion the failure began there and when the channel was sufficiently weakened the bulkhead began to flex tear and fail around the heavy rigid mounting plates Finally they both failed completely freeing the motor transmission assembly Both these center floorboard pieces ARE removable Problem is
15. any gear is the clean up After the gear has been removed and disassembled it must be impeccably cleaned in the solvent bath If there s paint to be removed use paint remover and or MEK as necessary Care must be used to prevent the loss of any bushings from the individual pads use a piece of safety wire loosely twisted through the hole and bushing to prevent the loss or misplacement of the bushings At this point let me suggest that you as owner get personally involved in the project along with your A amp P This is an outstanding opportunity to clean and repaint your wheel wells Also at this point it s not difficult to remove the strut for cleaning resealing if needed inspection and to gain access for your wheel well work Of course the AD doesn t specifically require this but it s a heck of a lot cheaper to do this yourself with A amp P supervision as opposed to paying him to do it for you And you ll be SO proud of your nice clean wheel wells The same goes for the gear motor If there s any doubt in your A amp P s mind about it s condition pull it out for a trip to Webco for overhaul Wiring also falls into this category If your wiring is like mine was i e lots of splices cracked plastic tubing that s spelled original for heavens sake call Matt Kurke and order a new set of marked made to order wiring for your gear He also has switches if you need them Is this starting to sound like a complete gear overhaul Is there a
16. been learning a lot this year about what is happening to the landing gear on our COMANCHES In many cases it reminds me of what the sergeant said IF IT S POSSIBLE TO PUT IT ON BACKWARDS SOMEBODY WILL This certainly is taking place with the gear from what I m hearing from the members lately Let s just take for example the bungee systems How many of you know what position the bungee arms should be in with the aircraft sitting on the ground Better yet do your A amp P and IA know Also do they have the service manual It is required that they have it to work on your aircraft and return it to service The bungee arms have 4 different positions that the bungees will go on to ONLY ONE is correct Plus the arms from the left side will go on the right side with this condition you still have 4 positions NONE of them are correct When you have them on correctly the left side arm will be at approximately at the 4 30 position the right side arm will be at approximately the 7 30 position have learned from at least one case where the arms were put on the wrong side Then the same person completed several annuals and returned the aircraft to service Although the gear worked without any problem for some time it s my opinion that when you have things put together backwards you are never right You have an unairworthy condition This aircraft was sold and the new owner was unable to get the gear down From what have learned don t know why can easil
17. before with my mechanic and briefly with the folks at WEBCO didn t give much in the way of clues spent six hours or more trying several different methods none of which worked The following steps finally allowed removal of the dreaded stuck bungee arm 1 Behind the arm to which the bungee cord attaches there is a hole through which the bungee arm bearing and retaining ring can be seen If you reach in with a pair of snap ring pliers the retaining ring can be removed 2 Check that the hole is large enough for the bearing to pass through In my case had to remove the bolts holding the bearing support to get it to move forward a bit providing room to allow enlarging the hole slightly 3 Support the area around the bearing cut a piece of plywood to fit up in the cavity and around the bungee arm and two 2 x 4 s to brace against the floor and the plywood Place something against the end of the 2 x 4 s on the floor to keep pressure on the surface around the bearing My results from Step 4 indicate that the sharp blow provided to the arm may make all this support unnecessary took what considered to be the safest course 4 Reach into your tool bag and get your biggest slide hammer with the gripping jaws mine came from Sears Clamp the jaws on the bungee arm as near to the center as possible not at the outer end where the bungee cord attaches Hammer away with the slide and you should be rewarded with the bungee arm and bearing both comi
18. by the emergency procedure Be sure your gear warning system is operating properly and that the horn is LOUD It should be loud enough that even with noise canceling headsets on you can hear the horn without it being connected to your audio system Try to check it on every landing by reducing the throttle s enough to activate the horn while slowing down then adding power to silence the horn The switch s should be adjusted so that it is impossible to slow enough for landing without sounding the horn Of course this assumes that you did not EVER lower your flaps until the gear was down or you could very easily slow to landing speed with the gear up and not activate the horn You twin drivers must be very careful if making a single engine landing as you will generally not reduce the power on the good engine enough to activate the horn prior to the flare Thus you must remember to lower the gear as the warning system probably won t warn you in time to correct the situation am a firm believer that the gear flap interconnect warning system offered by Knots 2U LTD should be considered by all Comanche drivers In addition to its main purpose telling you that the gear is not down if you use flaps first it puts a large red light directly in your line of vision a back up to your gear horn in case it has failed Probably at least half of the single and twin Comanches that have flown while conducting my classes have either a horn that does n
19. cross wind heard a loud bang during the gear retraction sequence got a gear up light and flew to Brunswick GA approximately a 15 minute flight As entered the pattern slowed to 140 mph and lowered the landing gear The gear extended approximately half way and the gear motor breakers popped recycled the gear again with the same result That left me with the emergency gear extension procedure followed through with the normal emergency procedure however was not able to lock the gear in the down position contacted Brunswick Radio and notified them of the problem found as worked the emergency gear extension lever that something was stopping the gear from locking into position was quite concerned about breaking the gear extension lever it looked so fragile However kept throwing the lever forward to try to dislodge whatever was stopping the gear from locking After approximately 6 tries something broke loose and to our relief the gear locked into place Green light no horn It was a feeling of relief to feel the mains and nose wheel contact the runway We taxied to the FBO and found after a short inspection that the guide roller for the nose wheel was missing Also the track that the roller rides in was bent up against the cross bar on the engine mount ICS TIPS Chapter 7 Landing Gear and Brakes Page 26 of 103 GEAR FAILURE BENT EXTENSION RETRACTION ROD We unfortunately had to file an accident incident re
20. foot on the emergency gear handle and hold it firmly against the wheel well ED If the gear is properly adjusted and the downlock springs are installed per specification the gear should remain locked ICS TIPS Chapter 7 Landing Gear and Brakes Page 7 of 103 GEAR DOWN LIGHTS flew for a long time with an intermittent gear down light problem and finally found a broken wire in the nose gear switch wiring harness The safe way to live with the problem think is as follows John s description is for his twin We are researching the comparable method for the single Retard both throttles until you get a gear warning horn Put the gear switch in the down position Watch nose wheel in the mirror or watch the mechanism in the cockpit If the horn stops when the motor stops and the wheels look down your gear is down and locked he The reason this works is that the light and horn have separate wiring circuits through all three wheel down limit switches at least for the Twin Comanche A check of the wiring diagram for the single would confirm whether it also has the same arrangement ED It does GEAR DOWN LIGHT A recent frustrating bout with gear position lights on my beautiful PA24 260B might be of interest to other members Over a period of weeks had experienced occasions where the green gear position light would either 1 Not come on or 2 Come on after 5 10 second delay or 3 Flicker after coming on h
21. forward during roll out By yourself Can you do it Co pilot aboard If we cannot extend all gears you have won the 12 000 first prize for a belly landing or the 4 000 second prize for a partial gear landing We had hoped to avoid that Gear up Landing Our first suggestion on a gear up landing is to declare an emergency and accept all the help you can get ICS member Gordon Graham reports on Tips page 344 a belly landing slide of almost double normal length followed by a fire caused by grinding the belly fuel drain A long landing surface minimum fuel and emergency equipment is therefore recommended Grass would most likely cause less belly damage but what grass field has emergency equipment Long enough The Piper handbook recommends landing with flaps up to minimize flap damage but the airplane floats considerably with zero flap and previous practice is recommended If you have passengers they are most likely apprehensive and some reassurance is indicated The airline bracing position of leaning forward with head in lap holding onto the lower front seat supports is possibly best for rear seat passengers We do not anticipate serious injury but you might save some teeth Brace in the direction of flight not backwards If two gears are inoperative step 2 recommends retracting the third due to loss of nose wheel steering loss of both main gears is deemed impossible At 20 feet we left you with only 3 things on your mind fuel selecto
22. have done in this situation Yep off came the emergency gear lever door and the emergency gear extension procedure was executed all to no avail The Landing Gear Was Stuck Halfway Up or halfway down There was nothing left to do but to declare an emergency and bend the bird s belly the prop got bent too It cost a bunch to fix the whole mess up again An expense that was not really necessary What had caused the mishap It seems that the aligner assembly was misaligned so that the aligner did not align In other words the roller which was supposed to ride down the inside of the Y had jumped out of the Y altogether and once out it could not find its way back in Hence the gear came up crooked and would not return to the down position because the roller was caught outside the Y How can one detect the misaligned aligner assembly It s relatively easy if the plane is parked in the bright sunlight or there is a good flashlight handy The aligner Y is usually dirty oily or slightly rusty however the track made by the roller can be plainly seen as a bright shiny line on the inside of each arm of the Y This track is kept clean and shiny by rolling action of the roller as it does its straightening job when the gear comes up Check very carefully to see if the shiny track is very near the edge of the Y or if it extends near the edge during part of its track If this is ICS TIPS Chapter 7 Landing Gear and Brakes Page 5 of 103 the case the poss
23. in this type of NDT The other was obvious but the first just wasn t there for me About that time read Maurice s article on whether the dye pen procedure is really good enough for this application and it got me wondering so as was doing the 1 000 hr gear bushing AD sent the studs from Harley s airplane to Hadco for Magnaflux They came back defect free but still wondered about the dye pen process so called Hadco and asked if they would re inspect the defective studs from the 250 with both Magnaflux and Type Fluorescent to compare results These people were great taking me through the whole process explaining step by step and showing me the hairline crack couldn t find After Magnaflux the parts were cleaned then checked with dye penetrant Mr Haddad owner did warn me that possibly some of the Penetrant from the Magnaflux would remain in the cracks giving a not quite true dye pen test The hairline crack was barely visible using dye pen not nearly as plain as with the Magnaflux procedures Mr Haddad gave me a thorough explanation on the merits of both procedures bottom line being if at all possible use Magnaflux as it will find defects that dye pen will miss Another caution is when cleaning parts for testing DO NOT wire brush or bead blast as this may cover cracks to the point being undetectable Use a good solvent and soft brush use 1 1 1 Trichloroethane with good results If anyone is interested in the different metho
24. information is basically the same for all of our aircraft both single and twin models Piper service letter 575 follows for your information ELE SERVICE Customer Services L E T T E R Piper Aircraft Corporation Lock Hoven Pennsylvanio USA March 10 1972 Subject Nose Landing Gear System Inspection Models Affected PA 30 and PA 39 Twin Comanche Serial Numbers Affected 30 2 to 30 2000 incl 39 1 and up Compliance Time Recommended at the next 100 hour inspection and each 100 hour inspection thereafter Purpose Product serviceability information received at the factory indicates a that the nose landing gear system is possibly not being inspected and or maintained at a level necessary for proper operation of the system It is therefore recommended that the following specific areas of the nose landing gear system be carefully inspected at each 10 how inspection ICS TIPS Chapter 7 Landing Gear and Brakes Page 52 of 103 Instructions With the aircraft on jacks 1 Inspect the nose gear aligner roller for indications of excessive wear and improper function and impact the aligner roller mount for security 2 Impact the nose gear oleo strut housing assembly and the strut housing collar for the following condition a Cracked stops b Broken and or missing stops c Nonconformity with nose gear steering travel information contained in the current issue PA 30 39 Service Manual Section VII paragraph 7 13
25. is its 38 BUNGEE CORD TOO sr ds 39 PUMPED UR SS TROD ti A ie e bis 40 GEAR DOWN Li A Tari 41 TWIN GEAR SIDE LINK BRACE 30 ccconos cronicas daa despedida Aa eaaa r oa nieee TE Ap dedicada 41 GEAR POSITION INDICATIONS cit ata ias 41 GEAR TRANSMISSION aora crio 42 AD 77 13 21 PREVENT GEAR COLLAPSE soriana Demis eidihedeveats 42 GEAR TRANSMISSION cuna A A AA 43 GEAR WARNING HORN SYSTEM scooter A Ena 44 GEAR WARNING HORN MODIFICATION coccconcccccononnccccccnanccnonannn nono nnnann cnn rra n nn cn rnna nn nc nnnannc nro 44 TRE TUBES tia ad EOS E E ius 45 GEAR TRANSMISSION MOTOR urinaria 45 GEAR BUNGEE ARMS disinari iieii teie ieda A iD AREA A 46 SHIMMY DAMPENER REPLACEMENT vices inccncsdscnccewncsatencareasarenvvagudeesunaeunessnoseubeciabancattanessneetsns 46 GEAR FAILURE LOOSE GEAR LINKAGE yes ccnsauccseknanetedesiaiaetinasiunnnarasonmieanenennerueiereanas nena 47 GEAR ST STEM A A E oa E E A A ET 47 GEAR WIRING sinat raa ae Ae 48 GEAR TRANSMISSION BROKEN WORM SCREW 000o oe ee cess ee eeeeeeeeeeaaeeeeeeaaaeees 48 BRAKE LINING FOR STAINLESS STEEL DISCS vc cicccictcstssnttveensinceasvesscccurddenessorseteeeestonetioease 49 GEAR BUNGEE ARMS dis 49 GEAR DOOR CONNECTING ROD arhantina ger a an ardana aea daa aaa ada da date ideada 50 GEAR UPPER DRAG LINK BOL Tiara dd 50 CRACKED SIDE BRACES PUD adidas 51 NOSE GEAR DAMAGE contaras ari AAA AAA 52 GEAR CRACKED HOUSING wii creat ii E tos 55 LANDING GEAR TES Vrscsciicncedsts chasicsneteauta
26. leg wired in series so that all three had to be made to illuminate the green light My first thought was that there was an internal short in the nose limit switch Thanks to the diligent crew at Airtech who tracked down the real culprits The gear limit switches were mis wired to such an extent that you only needed one main gear down ICS TIPS Chapter 7 Landing Gear and Brakes Page 62 of 103 to get a green light in effect bypassing the other main and the nose They also found a minor glitch in the service manual s wiring diagram that had the green and orange lights in series BUNGEE TOOL MauriceTaylor ICS 00775 The Bungee Tool can be made easily from almost any wood hardwood being preferred used white ash for mine With a 24 x 2 x 3 4 piece of wood mark out a center line Locate from the drawing the two points and using a fly cutter drill a 7 8 hole at one end and a 5 8 hole at the other end Saw to length as per the drawing and saw out notch as shown on end with 7 8 hole With saw or plane taper as shown The smaller end now is shaped by a modified 18081 00 roller With a three cornered file file saw teeth on roller and these need to be quite deep down to center radius to shape the center portion of the tool This can be done freehand as it does not matter if the teeth are not quite even Now with a 5 16 AN bolt 2 long thread it down so that a nut will grip the roller This leaves about 1 of bolt to mount in a drill
27. liner had broken off and wedged itself between the wheel frame and the tire thereby preventing the gear from extending either by normal or emergency methods It was also found that the landing gear motor release handle was incorrectly adjusted and did not permit motor disengagement ED If the motor could not be disengaged then emergency extension was impossible The main accident causal factor attributed was improper maintenance GEAR TRANSMISSION When gave Charlie s landing gear an inspection after this aircraft had recently had its annual found bungees so weak that could have pulled them off the rollers by hand although did use my tool to remove them The bungee tubes were OK because those bungees were too weak to put enough load on the bungee arms to cause any cracks Our inspection also revealed several dry bushings and hinge points especially where grease fittings were hard to get at Upon taking out the Dura landing transmission and opening the transmission housing found just what expected to see grease that had hardened over many years to the point that it had to be picked out piece by piece The gears had run dry for so long the teeth especially those of the driven gear had worn so thin they looked like knife blades recommended to Ken and Shirley that they should either replace that transmission or have it rebuilt soon as itis only a matter of time before those teeth will strip In the meantime after cleaning t
28. new ones as they are issued plus a yearly checklist to provide to your mechanic The FAA website site has a list of all AD s issued on all aircraft It is extremely time consuming to attempt to locate all AD s applying to your aircraft engine and accessories One of our members in Canada passed along the tip that the Canadian Transportation Ministry has a website www tc gc aviation continaw ad html that lists all AD s plus many SB s and SL s by aircraft registration number Canadian C numbers and by aircraft manufacturer and model All of the AD s are listed by number and can be downloaded to your printer The web site appears to be very popular and is occasionally overloaded Your mechanic probably subscribes to a commercial service that provides him with updates on a CID on a regular basis Try asking him to give you the next to last CD They generally discard them What do you do now that you have this list of AD s and the above Service Letters and Service Bulletins Find a little quiet time and sit down with your logbooks and check to see if you have any that have not been complied with If you find any that have not been complied with please have them done now Not at the next annual We all know that no one that sets out on a car trip or airplane trip expects to have an accident We all expect the gear to operate properly every time that we activate the switch Your chances of that being the case on every flight will be enhanced by prope
29. of accidents excluding gear related ones is hence 41 compared to 23 during my survey A meaningful comparison also requires the number of hours flown as the accepted factor is the number of accidents for 100 000 flying hours which don t have cannot jump to the conclusion that the safety record of the Comanches gear set aside improved In general though the AOPA ASF observed and reported a continuous decrease in the General Aviation accident rate during the last years The surprise is however in the landing gear accident figures An annual average of 3 for the AOPA survey compared to 31 during my survey a factor of ten Further conversations with the AOPA ASF enabled to conclude that this remarkable difference is not due to a sudden decay in the flying qualities and maintenance procedures of the fleet but to different definitions The AOPAASF study is based on the NTSB database which includes nearly only accidents see appendix As most gear related accidents are defined by the NTSB as incidents the NTSB neither investigates nor includes them it its data Therefore there is no contradiction between the two studies However the NTSB definition may have contributed to concealing the real magnitude of the gear problem As far as the affected owner is concerned am sure he or she does not care whether the case is called accident or incident but is more concerned with the consequences new prop teardown of the engine and more
30. or Nulon A35 STP and Nulon are brand names but consist of P T F E compounds manufactured by Dupont Another additive you can use is collodial graphite in powdered or liquid form Other control cables can be lubricated this way using the same style of operation with a longer piece of tubing for greater fluid capacity The throttle mixture and propeller cables on the PA30 due to their length may have to be approached from both ends This operation is a very messy job as oil will exude from areas along the cable and penetrate the fuselage area involving extensive cleaning up Therefore do not wear your best white shirt and tie After reassembly and adjustments for some time afterwards particularly after each landing the cable slide tubes in the wheel well area has to be wiped clean as lubrication will continue to be expelled at each gear cycle Failure to do this will result in the lubricant collecting dust and you will soon be back to the same old drag again ICS TIPS Chapter 7 Landing Gear and Brakes Page 100 of 103 GEAR DOWN LIGHT The gear mechanism works great but the green light doesn t work in flight This problem occurred recently on Tres and Janice Renniess PA30 After much head scratching and work we discovered a way to trouble shoot and fix the system The following is a sketch of the green light circuit This is a simplified sketch In order to understand the total system one should locate a schematic from the servi
31. or any Comanche owner The 1000 hour inspection is required by AD 77 13 21 and the details of the inspection criteria are contained in Service Letter 782B dated December 1 1977 This inspection if religiously completed is the foundation of a properly operating landing gear It s only when our gear is abused by the operator and not maintained at acceptable standards that we re likely to encounter problems As an aside in my rather limited experience as an A amp P have seen many 1000 hour inspections that have been signed off with nothing done other than the installation of bungees if needed My own aircraft never had the full inspection completed until nearly 3000 hours had passed and the AD 77 13 21 was signed off only when new bungees were installed Needless to say this was before got serious about my own maintenance To do the inspection there are a few specialized tools required They consist of a micrometer a set of go no go gages and a multimeter for checking the switches The ICS has a set of gages test bars available for loan from Maurice Taylor but had a set made for my own use They re great time savers So let s get on with it ICS TIPS Chapter 7 Landing Gear and Brakes Page 78 of 103 First we jack up the bird and remove the wheels and bungees and then come the removal and disassembly phase of the gear itself make it a point to keep all the parts from one gear isolated from any other One of the big jobs on most
32. point Mark a chalk line on the floor using the plumb lines as references You now have the true center line With the rudder pedals clamped in the neutral position adjust the steering push rods to align the nose wheel by sighting down the chalk line Do not adjust one rod end but divide the adjustments amongst all four ends ensuring that the threads do not extend beyond the check holes in the rods When you have the nose wheel aligned adjust the pedal bar angles to 13 aft of vertical Measure 20 either side of the chalk line a line intersecting with the nose wheel contact center point on the floor Check that the nose gear turns 20 left and right but not more than 25 If it turns more than 25 check for broken steering lock stops on the nose gear housing Allowing travel of more than 25 causes the rudder stops to contact and strains the cables and pulley attachments Having done this the rudder cables will have to be re tensioned RUDDER ALIGNMENT Following on from the previous article and whilst the aircraft is still on the jacks we can continue on to the rudder alignment With the rudder pedals clamped in the neutral position and the nose wheel aligned on the center line disconnect the rudder trim rod at the steering arm Adjust the trim indicator to read neutral ICS TIPS Chapter 7 Landing Gear and Brakes Page 57 of 103 Turn the trim barrel in the engine compartment to maintain the following distance from the barrel to the firewall
33. pressed into a hole in the middle of the brake cylinder You should not be able to move this bushing by hand pressure It does have to be set to its starting position use a 3 C clamp for this Laying something flat and stiff across the back of the brake cylinder the C clamp can be centered and tightened in order to push the retract cylinder back flush with the same surface that the pistons are flush with The retract cylinder should move fairly easy this way Now the new pads can be riveted on and everything can be reassembled although there is an adjustment that has to be made the spring amp sleeves and the nut amp washer The nut should be self locking If it moves too easily it should be replaced with a new all metal self locking nut Now tighten the nut down so that the washer doesn t quite touch the exposed end of the retract cylinder about 1 32 space is good This setting is how much the brake pads will be pulled away from the brake disc after brake application See diagram 1 When tightening the back plates down make sure the tire can roll freely at all times The back plates have pads mounted on them with three rivets each and are tightened down with 1 4 bolts that have 7 16 heads If the brakes lock look for this possible situation See diagram 2 Now that everything is tightened down go inside the plane and push on the brake pedal several times After the second or third push the pedal should get noticeably harder T
34. spot in the wiring in the left well caused by contact with the wheel during retraction in flight B Ihad this problem with my 1962 Comanche found the problem to be corroded contacts in the gear down switch itself The way the switch is wired one portion can fail light indication while the other continues to work motor down limit and gear horn To remedy the situation changed all of the micro switches including the squat switch presuming if one is bad they probably all are bad When disassembling the switch from its mounting would suggest replacing the rubber washer located between the switch and the housing Attention should also be given to the boot over the plunger The switch can be purchased from most local wholesale electrical supply houses It is Microswitch DT 2R A7 TWIN GEAR SIDE LINK BRACE Had an experience with the Love of my Life 66 Twin which hope may be of value to someone else out there During the annual my trusty mechanic in whom have great faith discovered that the right main gear side link brace had a very sloppy fit with the rod end into which it threads There was so much end play that it looked as if a good hard jerk might pull the two pieces apart in spite of the threads It s pretty hard to visualize how this could be a result of wear even after countless cyclings of the gear over 21 years mean threads just don t wear that much unless they re screwed and unscrewed There was no appearanc
35. the mating pin on the torque tube B The clevis pins A much rarer situation occurs if you find one of the clevis pins has lost its cotter key and the clevis has fallen back into the tube If you have worked the gear motor by now you have ground up the clevis in the worm drive Don t despair This can be fixed 1 First of all you must remove the gear transmission and gear motor 2 Remove the cotter key on me opposite side of the assembly and push that clevis pin back inside the tube You can now remove the red arm release tube assembly and the bushing it attaches to You can see two holes approx 3 16 inch diam on the sides of the tubular drive shaft These serve as a recess for the clevis heads to rest in so that they don t interfere with the transmission screw inside 3 Twist the transmission screw up to the bottom of the holes and holding the whole apparatus motor end down tap lightly on the side of the drive shaft tube and see if you can fish any metal debris as well as the good clevis you just pushed in out from inside the tube If you can easily screw by hand the drive shaft tube up and down the shaft chances are you don t have any metal left inside 4 assume that eventually you will want to put all this back together and here s how Get two new clevis pins and cotter keys The clevis pins must be identical to the old ones not just close If you have studied the reassembly of this drive shaft bushing arm you realize that i
36. the proper entries are made in the logbooks The FAA and Piper work together to correct problems as they are recognized When the problem results in catastrophic or frequent failures the FAA issues an Airworthiness Directive These directives are mandatory and generally have a compliance time It is the pilot s responsibility to see that the requirements are accomplished within the designated time period The pilot also is responsible to see that the proper entries are made in the appropriate logbooks The A amp P has the responsibility to enter and sign off the work that he she does The pilot has the final responsibility to see that this is done Piper issues Service Bulletins and Service Letters as situations are identified as problem areas They may contain recommendations to install certain kits to resolve the problem They may recommend changes in inspection intervals or lubrication intervals or procedures In many instances the problem is first identified in a Bulletin or Letter and then when the AD is issued it refers back to the Service Letter or Bulletin for the proper corrective action The point needs to be made that a Service Bulletin or Letter is only issued after a problem area is identified When they are issued you need to be concerned Apparently some mechanics and some owners rationalize that AD s have to be complied with while Service Letters and Bulletins do not carry a FAA mandate and are therefore optional This rationale
37. the seats inboard tracks floor to spar fairings fuel selector trim etc must come out first have made a modification of the center aft floorboard and its mounting system to allow either removal of the entire section without seat track removal by installation of mounting angles on inboard side of the fuselage beams to take PK screws and Tinnermans or an inspection plate over the area to the left of the fuel selector This would require FAA approval Then checking this area could become part of Annual inspection procedure Seats come out and fuel selector trim off in less than 20 minutes so no appreciable increase in Annual costs Every so often since 61 purchase with mechanics setting up the gear on jacks so that in flight they try to come up too far and blow the motor C B This feel is the primary reason for the over stressing and failure of these parts Other owners who have had retract C B popping problems would do well to have that channel checked visually at the next downtime Replacement once access gained is quick and easy The channel is easily fabricated locally and suggest forgetting the lightening holes Comparable A C with no previous up problems C B popping or trans failure would probably not have any damage to the channel or bulkhead think the extra nose gear springs are not helping this situation but it would take time for this extra load on the retract cycle to cause this sort of fa
38. the winter My 250 C GCRM fired up after some coaxing and taxied out behind C FMFB a 260 owned by Joe Chomany We had no particular destination in mind but we planned to look at the mountains and perhaps stir up a little air and maybe even visit some friends at a local field applied brakes as approached the button and lo and behold nothing at all happened they were frozen solid felt betrayed and disappointed but there was no alternative but to do a quick 180 and return to the tie down The mechanic at Arrowhead Aero was not busy so he warmed the old dear in the hangar and then drained the brake fluid Sure enough there was moisture evident He then suggested that we had better look at both wheel cylinders as he explained the drain on these is not at the bottom but rather at the side of the unit and water can collect in the lower portion of the wheel cylinder ICS TIPS Chapter 7 Landing Gear and Brakes Page 15 of 103 We removed both and was shocked to find the bottom half of each unit to be filled with a gooey emulsion of oil and water What a mess Further inspection revealed that one cylinder had been corroded by this guck and would have to be replaced We cleaned everything replaced the seals flushed the system and had everything functioning in a couple of hours have no idea how the water entered but we suspect condensation as we know that it seldom rains in Sunny Alberta For those of you who have not inspected these
39. they are not trying to force the aircraft in one direction whilst the pilot is trying to steer the aircraft in a straight line down the runway The first step in ground rigging the aircraft is to jack the aircraft and get it horizontally and laterally level We start by getting the nose wheel to run a true line with the center line of the fuselage The important thing to note is that the nose wheel of the Comanche does not set on the true center line but sets to the right hand side somewhat There are two methods of aligning the nose wheel One is to use a Jig especially fabricated for the purpose the other is by the chalk line and plumb bob method As many of you would not have access to the aligning Jig will deal with the latter method here With no load on the nose wheel check the clearance of the steering rollers to the steering bellcrank These bushes should rotate with a slight drag and have very little clearance If clearance is excessive correct it by fitting the appropriate oversize roller These are available in sizes 0 625 D 0 687 D 0 750 D 0 812 D and 1 D Place a suitable length of bar across the nose wheel tunnel resting on the forward edge of the fuselage skin below the nose wheel drag link hinges Measure from the inside lower wall of the nose wheel well on the right hand side 5 and tie a plumb bob weight to the bar at this point Measure 0 5 to the right of the rear tie down point and attach a plumb bob weight at this
40. you ve done everything correctly this step is really a waste of time You can feel the gear with the emergency release handle and tell if there are any restrictions or binding If there is any binding go no further until it s fixed So you ve got it all back together and your A amp P says its right You reconnect the motor and cycle it a time or two Make sure you have a charger on the battery so you don t drain it Go down and wiggle anything moveable and make sure that the lights are appropriate You may want to adjust the up limit switch at this point to insure that the gear fully retracts to the rubber bumpers When you re happy with everything try an emergency extension Play particular attention to the amount of force required to disconnect the motor Be sure to restrict the gear from falling full down If force required is excessive you have your up limit switch too tight too much pressure upward against the rubber bumpers So adjust it a bit Then check the safety switch squat switch for proper operation Now you re finished Right Wrong You haven t completed the paper work Make sure the log entry includes the reference to AD 77 13 21 to SL 782B and the fact that it s a 1000 hour inspection When you re both totally satisfied with your work it s time the TWO of you took the bird up for a test flight Is everything up to speed Of course it is It s up to speed because you and your mechanic have done a quality job Check normal
41. 0 250 you would automatically get a heavy walled bungee arm as Piper no longer made thin walled ones If your 180 250 still has the thin walled arm they should be checked every time you change the bungees If the arm is in good shape see no harm in putting it back If you find it cracked it must be replaced Replace it with the heavy walled unit as that is the only approved replacement part We have talked about these arms in the past but obviously the problem still exists ICS TIPS Chapter 7 Landing Gear and Brakes Page 60 of 103 Bungee Arm showing position of Cracking PROBLEMS WITH GEAR Maurice Taylor Technical Director You may be saying to yourself oh no not another article on the landing gear Yes indeed and obviously needed with the calls have had recently about gear up landings In almost every case lack of knowledge about the gear and its workings was at least partly to blame for what happened Possibly neither the horn or the light was working and perhaps the check list wasn t used Sounds all too familiar Fortunately for those owners have talked to in the last couple weeks they were lucky as their airplanes are repairable If for any reason the gear does not go down by the normal method do not be too quick to disconnect it and use the emergency extension This should be the last item on your check list and used only when you have proved nothing else will work 1 Know where the circuit breakers are
42. 0846 01 for the right The tube of this arm which supports one side of the main gear has a wall thickness which is thinner than the bungee arms on the 260 s the 400 s and the twins These have been no problem The arms on your 180 or 250 have to be removed to check them for damage and if this has not been done on your aircraft in some time it would be wise to attend to it PLEASE NOTE There are three positions these arms will go on but only one right way 1 The left one will go on the right side the arm then is in the wrong position The arm can be rotated approximately 180 and it will go on Again the arm is in the wrong position 3 The right way When viewed from behind through the opening where the bungee is housed and with the left gear in the full down position the bungee arm should be approximately at a 4 30 to 5 00 position On the right gear the arm should be at approximately 7 00 to 7 30 These arms can be obtained from Av Pac by calling 800 228 1836 Bob Weber of Webco Aircraft Services also has these parts available If you order a replacement arm you will get 20846 06 for the left and 20846 07 for the right These will be the heavy walled ones that are on the 260 s the 400 s and the twins SHIMMY DAMPENER REPLACEMENT In mid 1987 ICS called me on one of his many tireless parts hunting rounds looking for a new Maeco Shimmy Dampener that just might happen to be left over from the great flood or maybe a
43. 15 NOSE GEAR SUPPORIT CORROSION asistan bid 16 GEAR CIRCUIT BREAKER minn nenat thas enter a a e ar i a daea i 16 TWIN GEAR MICROSWITCH WIRING Sui 16 GEAR BUNGEE ARM D ae aa a a a r ae e Eea aa ADEs aa Aaa EAA AA iiA NEn aded Aia TARANEE ESATA 18 GEAR TRANSMISSION a AS 21 AD 713 21 PREVENT GEAR COLLAPSE tear ontario 21 GEAR WARNING HORN ADJUSTMENT occciorciiniinra ci d cc 23 LOW BATTERY EFFECT ON LANDING GEAR icicciscccincetestersnvenececnendcuesecbeudddecetenssbinessversaterende 23 MAIN GEAR BOLT PREEZEUP nuca pain 24 LOW BATTERY EFFECT ON LANDING GEAR c cccccocccccccccccnncccnonnnccnonannnnncnnnnanoncnnanan cnn nranna cnn 24 GEAR MAINTENANCE a e e a a r a a dobtnetuaeases mhtsannacp tadusadtthonsuetedeesndestencavencceens 25 GEAR TRANSMISSION reagan a a a a aei 25 NOSE GEAR DOOR WORN HINGES 6 vec stecics cacne deeds cra da dicte 25 JAMMED GEAR EXTENSION cora Maine 26 GEAR FAILURE BENT EXTENSION RETRACTION ROD ccccccnccccccconononononononcnonanncconanacannnn 27 GEAR FAILURE MISSING SPRING AND COTTER PlN ooocccccccnnccnnccnonannnncnonano conocia ncnncnanancnos 27 NOSE GEAR WORN BELLCRANK AND BUSHINGS oocococccccococnncnonanononnnnnano nono nanan cnc ncnnnnnnannnns 30 GEAR BUNGEE ARM Sissi a iia 32 ICS TIPS Chapter 7 Landing Gear and Brakes Page 1 of 103 GEAR FAILURE JAMMED WHEEL WELL LINER cece eeee ee eeeae settee eeeneeneeee 35 GEAR TRANSMISSION taaan cinta caia Rate e ea iatea acacia nadia diaria 35 STRUT MAINTENANGE Sri
44. 2 and Misused emergency gear system 1 PREVENTION The AC recommends Have a condensed checklist mounted in full view for easy reference Periodically review the landing gear emergency extension procedures Be familiar with the landing gear warning horn and warning light systems Review the procedure for replacing light bulbs in the landing gear warning lights and carry spare bulbs Have known landing gear deficiencies corrected before flight Complete your landing gear checklist on the downwind leg or at the final approach fix inbound to ensure that action is taken to lower the gear and recheck geardown indicators before landing Do not touch any levers or switches until you complete your landing roll and clear the runway MECANICAL FACTORS Of the 39 accidents attributed to mechanical failures most were caused by improper rigging and adjustment lack of lubrication or inadequate corrosion control Factors that would pertain to Comanches included Metal fatigue failure Improper installation or improperly secured parts Use of non standard parts Failure of electrical wire connections relays contactors and or actuators Malfunctions of warning systems Inoperative limit and safety switches Failures of downlocks Wheels jammed or hung up in wheelwells Cables fouled Glide tubes bound due to contamination and corrosion and Torque tubes and drag struts bent due to excessive loads MAINTENANCE The AC recommend
45. Brakes Page 29 of 103 gear go down and locked Not caring to further improve the situation at that time landed the airplane without making further engineering changes in the geometry of the gear extension Soon after landing found time to read the PA 30 Service Manual on Landing Gear and the ICS Tips on problems other people have had with getting all three wheels in the best position to land on find that our opinion of the cause is different than we have learned of others Hoping it will help someone avoid the indignity which came near to facing enclose a copy of Fig 7 14 from the PA 30 Service Manual and a suggestion of some adjustments you can check for yourself just by taking the cover off the gear mechanism well You should have 10 875 between the center of the transmission mounting pin and the center of the through bolt 13 connecting the lower part of the torque arms This adjustment should allow approximately a minimum of 0 125 measured along the actuator screw 14 between the roll pin stop 16 and the screw nut 15 The above paragraph is quoted from 7 36 of the Piper Service Manual You can take the top cover off and check the adjustments with no more than a 12 rule Popping a breaker is small irritation but it is no big deal as long as the emergency extension system works The transmission motor and actuating screw is spring loaded by the retracting spring 23 When the release lever is released the retracting spr
46. Do not continue with remaining items of the present section Double failures are not considered ABNORMAL GEAR OPERATION CHECKLIST If Green Gear Light Not On 1 Do not recycle gear Move gear switch to OFF and then DOWN at least twice If green light obtained or at anytime hereafter proceed with normal landing 2 If green light not obtained depart traffic area to 3000 ft AGL set power and monitor fuel Fly the airplane ICS TIPS Chapter 7 Landing Gear and Brakes Page 93 of 103 9 10 11 Remove transmission cover Inspect transmission for security and blockage Inspect for broken gear train components Check gear alignment stripes If transmission unsecured or jammed gear switch OFF Clear blockage if appropriate Proceed to manual extension If gear train components broken and one gear in op proceed to appropriate partial gear landing checklist If both nose gear and right main in op left torque arm proceed to Gear up landing If gear stripes matched but not aligned full travel proceed to next section on Gear stripes not full travel If all stripes aligned full travel and components not broken recycle gear at least twice in an effort to obtain green light If unable green light and stripes still aligned full travel reset all breakers amp test gear warning circuits a Cycle light dimmer to detent several times b Cycle gear indicator light CB several times c Test warning horn at retarded throttle to
47. EMS David R Clark ICS 8592 Most of us have enough sense to know if our gear motor and transmission are not working smoothly or sounding right If they aren t we repair them immediately because we don t want to be at the mercy of the emergency gear extension mechanism even though theoretically it is designed to get the gear down no matter what A problem arises when our backup system doesn t work i e the release arm doesn t uncouple the landing gear from the motor drive shaft Many of us may be vaguely aware of how this system works and a few may have even pulled the handle when the plane was up on jacks at annual inspection Maurice Taylor encourages us to familiarize ourselves with this system while on the ground and to learn how to reattach the extension mechanism to the gear motor so that we might eventually be able to practice lowering the gear by the emergency system while in flight and then be able to reattach the gear to the motor again prior to landing Note Piper advises us that if we utilize the emergency gear extension system while in the air the proper technique is to land the airplane and put it up on jacks and reattach the gear motor torque tube to the landing gear drive shaft You can judge for yourself what you are comfortable with but not being knowledgeable about this system may unnecessarily distract you at a time when other things demand your full attention Don t try activating the emergency system in the air for practic
48. It took two men with shoulders against the back seat using their feet to get the gear down with a full blown airport alert at Burbank in my case The other two were less fortunate and made wheels up landings At Lockheed we would impression stamp these parts to assure correct installation during routine maintenance procedures and even this would not prevent Murphy s Law but it would help The FAA should revise their AD s to simplify inspection procedures to the fore and aft and transverse play criteria and require tagging of bungee roller cranks as left or right when they are removed for maintenance and all these so called problems would go away ICS TIPS Chapter 7 Landing Gear and Brakes Page 20 of 103 GEAR TRANSMISSION Recently had occasion to help out with a Comanche Transmission for lifting and dropping the retractable gear The old fuse pop problem that many of us are familiar with First replaced the motor which had indeed burnt one of the strands in the armature winding was black and was not able to get a motor replacement for an associate of mine Also there was excessive play in the gear box itself and a 57 thou shim did wonders to take out the play Had to install the shim between the ball bearing and the ball bearing case right in the transmission itself a real simple task since we have our own machine shop and an excellent machinist Wouldn t you know it still have a fuse pop problem Stripped it down aga
49. Page 99 of 103 LEGEND 1 Inflation Valve 2 Hose Clamp 3 End Plug 4 Clear plastic Tubing Heavy Wall Nylex or Tygon Place the aircraft up on jacks and disconnect the gear cables at the outer ends of the cables in the wheel well area Disconnect the nose gear push pull rod Remove the rod ends from the main gear cables at the wheel well end Remove the rubber dust cover from the swivel joint on the cable Remove the spider bracket from the wing spar Remove the castle nuts from the outer cable and slide the spider bracket from the cable This leaves the cable free to be moved around when attaching the lubrication tool With badly stuck cables it is preferable to force a cleaning medium through the cable first to remove all of the old gunk With the cable held in a downward position approximately 2 3 fill the tool with cleaning fluid and slide off the cable and attach as depicted Hold the cable upwards as far as you can and apply air pressure to the inflation valve approx 5 psi and whilst holding in this position have an assistant move the gear mechanism manually up and down to facilitate the progress of the cleaning medium use kerosene or paraffin When the level of fluid falls below half re instigate the process until a clear fluid issues from the other end of the cable Having accomplished this repeat the operation using lubrication fluid make up a mixture of light oil and friction proofing compound such as STP
50. TER RESISTOR ON FLASHER BOX GREEN LIGHT From the diagram one can see if a wire were to be used to jump from A to B briefly the light should go out and the circuit breaker will pop If we jumped from A to B briefly with a wire the light would come back on if the system was spiked with the master switch or the instrument light switch Using the jumper we induced the problem encountered in flight If the above trick caused the malfunction great If not don t despair If only flight will induce the problem put the aircraft on jacks cycle the gear and make sure the gear is functioning properly At this time it is a good idea to open up the emergency gear access cover and put a mark below the push pull cable ends in the full down position This mark will enable one to determine if the motor and transmission has moved to full travel in flight Alignment will not guarantee that the gear is locked but malfunctions past this point in the system are fairly rare While the aircraft is on jacks check the gear limit switch adjustment and the general condition of the wiring Careful attention should be paid to the butt splices corrosion fit etc Next cause the malfunction with the jumper wire or by flying the aircraft if you must Run a jumper from the seat track to the light socket housing If the light comes on the problem is in the limit switches and associated wiring If the light remains off the problem is in the other half of the system o
51. TIPS Chapter Seven Landing Gear and Brakes Table of Contents GEAR WARNING HORN caia aaa coca dines E A nites ued 4 GEAR FAILURE MISSING COTTER PIN ussrarataa in drid droit is 4 GEARMAINTENANGE rintasi aaa e AE A adrede 4 AD 77 13 21 PREVENT GEAR COLLAPSE arimea ana e aee a eA do 4 GEAR FAILURE MISALIGNED ALIGNER visteccisccccccivesctentendecendensdelendeeesstceveveqrsverasvbennsededcvetndidtes 5 BRARE Sr E E A E 6 JAMMED GEAR RETRACTION asnan teangannan A AI a 6 SINGLE FORK MODIFICATION e ee aaeain ane ida eeeh uiid maad a LELE daha isapa EE aaoi a a Taidat depi ia 6 POPPED GEAR CIRCUIT BREARE Soria a a a a a a A a tate 7 GEAR DOWN LIGHT Sisi A A AA A cad 8 GEAR DOWN LIGH Fosrricn i A A A 8 PUMPED UP STRUTS prre aeie p a a a a aa 8 GEAR CIRCUIT BREAKER e a aa ana a ra aaa crac ata nadien Rc daa 9 GEAR FAILURE GEAR COLLAPSE vns ar 9 HAND BRAKE SUPPORT BRACKET ririri eaan a a a aa aa 9 GEAR DOWN LIGHT ioien a a a a a a eed en eias 10 SLOW GEAR OPERATIONS sevi o 11 SYNG THE GEAR vna ea ae aaae N EEEa Seance wa eaa EAEE a 11 NOSE GEAR DOOR INCORRECTLY INSTALLED cocononccccnnccnncccnnancnccnnanncnccnaaannnoranannnnnnnns 12 TOR BRAKES oca A aa 12 GEAR TRANSMISSION LOOSE MOTOR sarita ies 12 OBSERVATION Su A o da 13 GEAR OPERATION Sci ae 14 JAMMED GEAR EXTENSION cs ii 14 GEAR TRANSMISSION ASSEMBLY a vccctiosisnnsdssjncceiwasetnecuredsctsagcasaevenadsdsncdeensdaasedeesndensieneedancboreg 15 BRAKE CYLINDER MAINTENANGE ina iio
52. The Comanche must be on jacks 2 Unhook gear at the transmission 3 Get under Comanche and visually determine that the main gear retract links come over center at the same time Adjust as necessary 4 Determine that the preload in the down position is about the same on both main gears Do this by pushing upward on the center of the retract link The important point here is not the number of pounds required to break the retract link over center but the fact that the values on both gears are about the same Adjust to get equal tension 5 Repeat steps 3 and 4 for the nose gear Remember that a Comanche gear is mechanical Therefore all three gears should come over the center at the same time and the tension ICS TIPS Chapter 7 Landing Gear and Brakes Page 11 of 103 should be approximately equal on all three gears John Dean looks for about 20 pounds pressure to break each individual gear over center It can be higher A lower value means out of rig and or worn gears Adjust nose gear Down Preload 6 Re hook the gear 7 Check for excessive play in the transmission bearing i e is it tight in the transmission housing There should be no more than 0 015 inches play in a fore aft motion If it is greater the worm gear will ride up on the ring gear and cause excessive friction If your gear passes these tests it is in sync Assuming that it is properly rigged and meets the over center limits it should continue to provide many years of t
53. ad the microswitches checked on all gear legs and had the gear system checked for proper adjustment of throw of all gear legs All checked out OK but still had the green light problem on occasion The gear motor always shutdown normally after the selector was in the down position At no time did pop a circuit breaker but the light problem was hard on the nerves even though I always had confidence that all 3 legs were down and locked and never had to land without finally getting a steady down indication after numerous gear cyclings The problem turned out to be a broken wire in the light circuit The break was inside a plastic sheath on the left main gear leg and was found by simply my jiggling the wiring on each leg while the plane was on the ground master switch on and a friend sitting in the cabin to monitor the light Perhaps someone else is having this problem or will encounter it and can save some time money and aggravation by checking in this fashion for broken wires PUMPED UP STRUTS Heavy landings are most undesirable any time but this is particularly so with the struts pumped up as you have less shock absorption capability So be very careful to avoid these If you lower the nose strut check your prop clearance This may be a problem if you operate over any grass areas since the clearance is reduced by several inches you will also find that the step up to the wing is much larger with the longer legs so mounting and dismou
54. allic Having gone through four sets of metallic brakes knew there was a problem A call to ICS got me to look at the disks Guess what we had stainless steel brake disks A call to ICS confirmed that metallic brake pads and stainless steel disks are a no no My TIP is simple if you have stainless steel disks don t use the metallic brakes GEAR BUNGEE ARMS After reading about the possibility of cracked bungee arms in the Flyer figured that annual time would be a good time to check this out To put it mildly am very glad that checked read over the description in the article consulted with my A amp P mentor and proceeded to remove the right bungee arm Well at least proceeded to try to remove the right bungee arm Contrary to my expectations the arm would not come out After trying to pull the right one for thirty minutes or so decided to try the left side Piece of cake It came out easily just as promised by the manual and article It was not cracked but a rather significant looking groove was present where the shims ride This to me seemed worse than the cracks shown in the article since the tube could split at the crack possibly letting the gear collapse Upon further investigation of the right side it was almost certain that the tube portion of the bungee arm was bent The pivot action when retracting the gear or turning the bungee arm was slightly eccentric Discussing what to do next and have you seen this
55. annual time that have overflown required inspections Several AD inspections on the Comanche series require 100 hour re inspection to comply with the AD text It is not acceptable to fly beyond the 100 hour re inspection just because your annual inspection is due next month An aircraft with good clean documentation is a joy to work on and shows the owner s knowledge and understanding of what is required to keep his Comanche airworthy and legal to fly Overflying an inspection or improper record keeping could come back to haunt you should there ever be an accident or insurance claim or heaven forbid an FAA ramp check EMERGENCY GEAR EXTENSION Maurice Taylor How do you get the gear down using the emergency method The very best method that have found is to work with a good flight instructor who can take you through the proper steps enough times so that you feel confident about it If you cannot find a flight instructor that is able and willing to do this for you although it is not as good you can practice it with the aircraft on good solid jacks but DO NOT DO THIS WITH THE GEAR ALL THE WAY UP as the gear will fall with a very hard crash and maybe damage the gear ICS TIPS Chapter 7 Landing Gear and Brakes Page 68 of 103 To do this properly see the LANDING GEAR VIDEO 8 for a step by step procedure You need to practice it enough so that you can do this in the dark One of our members lost the electrical system at night he had no pr
56. ar in August 1988 Upon removal discovered that the stem was one third of the way cracked from the tube pulled the stem the remainder of the way off with little effort dug out my old receipt and called Desser Joe answered and informed me that the warranty was expired and that tubes have a 1 year shelf life and that they recommend changing tubes every 1 to 2 years He said that might send the tube back and if they determined that it was defective they would probably send a new one sent the tube back and did a survey of 3 mechanics and several pilots who said they never changed tubes that often for weekend type flyers Meanwhile met a gentleman with a career in aviation tires and tubes who knew of thousands of tubes that should not be sold as they have valve stems in them which had been manufactured to the wrong specs The brass tube inside stops about 1 4 short of going all the way into the tube making a weak area was also told of an accident in which both mains blew on first flight and that these defective tubes could be identified by the name Bridgeport molded at the base of the valve stem I think Desser knows this same information too got goosy again and took the other tires back off and they said Schrader which is supposed to be okay so reinstalled the second time getting good at changing tires GEAR TRANSMISSION MOTOR might share an experience with the gear A new Bosch motor was installed On approac
57. arently over the past 34 years the shims have worn enough to relax the torque and cause looseness in this connection Another thin shim was fabricated and added to make the connection tight and restore the nose gear to a relatively safe condition From now on checking for looseness in the drag link clevis will be a standard part of my annual inspection by watching for it as the gear retracts Since finding my loose clevis I ve heard of others One shop that regularly sees Comanche gear estimates up to 80 percent are bad Mine was How is yours WIRING TO LIMIT SWITCH COMANCHE LANDING GEAR Pat Barry ICS 02198 During my recent extensive annual on N7523Y a 1964 PA30 observed a separated wire on the right side between the pivot attachment and the limit switch on the right landing gear During the work found another wire which had separated inside the plastic wire sleeve without having shown through which meant that the wire was touching intermittently clearly a double candidate for a problematic failure On closer inspection saw the wiring harness had been patched decades before and that the wire had broken due to the harness being secured on the pivot attachment and being tweaked every time the gear would retract and extend The original system on Pipers is not good in this regard The design is for the harness to be immobile on the pivot point held by an Adel clamp and the wire is bent in an S bend every retraction Eventua
58. at the nose wheel micro switch the gear horn the throttle switches and all associated wiring are not broken GEAR FAILURE MISSING COTTER PIN A couple of years ago had total electrical failure at night coming home from Massachusetts on IFR plan had three flashlights flew to Bangor International 11 400 by 300 to land Read the cover over the emergency release carefully and followed instructions and the gear lever came up 45 and stuck put a 30 degree bend in the lever to no avail so had to belly land Later was told that there is a cotter pin which supports the worm gear arm that had broken allowing the arm to drop enough to make it jam See article on Emergency Gear Extension Problems GEAR MAINTENANCE The secret have discovered to keeping the landing gear in top condition is to grease all the fittings frequently every oil change and to use high quality lithium grease on the worm drive gear The way to do this is carry a small tube in the plane and while in the air open the emergency gear cover plate and apply the grease it s the only time you can cover the worm drive completely AD 77 13 21 PREVENT GEAR COLLAPSE 21 Nov 78 Keith Blythe Chief Eng amp Mfg Branch FAA Atlanta Georgia Re AD 77 13 21 Dear Mr Blythe Reference Part B of this AD May I as pilot owner perform the repetitive inspection of the bungee cords on my PA 24 260 since this is one of the preventive maintenance items granted t
59. ave measured voltages had recharged our battery during the annual This made it possible that we were working with a higher voltage after the mod than before A higher voltage would give less current and faster action But we were not impressed that it was any faster this was what brought our attention to the precise timing need Another possible factor was the bearing surfaces without grease fittings which were not well lubricated Another factor was Pete s careful readjustment of the limit switches for up limit on retraction Something else caught my eye as saw Pete double checking each gear when all was reassembled He was sitting there on the floor with both hands on the right main gear trying to shake it side to side and fore and aft asked what he was doing and he said This gives me a feel for the total sideshake in the system now that it is in operational condition My reply was Well why don t we measure it So we did This was our method Pulling on the fish scale 5 lbs outboard we set the indicator to zero then pulled 5 Ibs inboard and the indicator read 0 020 The corresponding measurement on the right main was 0 030 This gave us a concise repeatable measurement of the accumulated tolerances in the whole operational system It is only an index reading because in with this is a certain amount of bending and a small amount of resistance due to lubricant in the bearing spaces did sufficient other measurements to de
60. back of the nose wheel well when the gear is extended Based on a tip from the Comanche Tips book always apply light pressure by pushing the bar every time extend the gear By assisting the gear have the opportunity to feel if any part of the mechanism is binding When the gear extends into locked down position there is a tactile thump as the gear reaches full extension In addition the position of the lever arm against the wheel well also can be used as a rough indication that the gear is completely extended then turned the gear switch back on and selected Gear Up and when the gear had retracted selected Gear Down again With the same result The gear froze half way through the extension This time immediately turned the gear switch to Off It was surprising that the circuit breaker did not pop There are two probable reasons that it didn t pop First both times selected Down at the first sign of the gear stopping immediately switched the gear switch to Off or Up so that the motor wasn t running against a jam Second later checked and found that the circuit breakers were very old most were original and might not have been usable or effective So had my A amp P replace all the circuit breakers Fly The Airplane First then notified the tower that had a landing gear problem and turned east away from the airport My intent was to find a safe place to sort out the problem flew away from the approach and departure pat
61. better time to do all this than when the entire landing gear is disassembled With the gear parts all cleaned and lying on your shop table it s a fairly simple procedure to check all wearing surfaces for unacceptable wear The go no go gages have the minimum diameter on one end and the maximum diameter on the other end The small end should drop right in the hole but the large end shouldn t If it does the wear is unacceptable and the bushing needs to be replaced All bolts are measured with the micrometer in the conventional manner and are replaced if wear is beyond limits These tolerances are all listed in SL 782B It goes without saying that the gages should NEVER be forced into a hole The main gear side brace stud commonly called swivel pin deserves some special attention Due to some failures in other Piper products it has its own AD to direct its inspection procedures The effective AD is 07 01 01 R1 which replaced AD 95 20 07 The name of the game on this little gem is to take it to your local FAA approved Magnaflux facility for checking If it has cracks it must be replaced There s no generalization that s accurate with regard to what parts are most likely to need replacing Having said that you should ALWAYS replace the over center springs and the bungees The most likely bushings to need replacement are in the nose gear drag links I ve found most of the swivel pins acceptable although in one case had to replace both of t
62. ccidentally filed away in the wrong parts bin Of course Maeco s had not been built for over ten years and finding a new one was like discovering teeth in a hen s mouth When one was found they brought up to 200 a piece Used Maeco s have been selling for 90 to 150 each ICS TIPS Chapter 7 Landing Gear and Brakes Page 46 of 103 Anyway to make a long story short ICS asked me if we d try to come up with a new shimmy dampener for the Comanche family one that could be repaired if it ever went bad said I d look into it Well two years later 20 000 poorer and countless hours of agonizing stress has finally produced the results asked for Airparts of Lock Haven has received two separate STC s from the FAA covering all Comanche and Twin Comanche models We have currently available kit FALH 001 for the singles and kit FALH 002 for the twins And as promised have kit ALH 1995 for repair of both above kits Kits though costing 33 higher than the last new Maeco s are better stronger prettier and come with a complete change of hardware including rod end and clamp for 297 50 Repair kit 22 50 Same Price Jr Airparts of Lockhaven Inc GEAR FAILURE LOOSE GEAR LINKAGE recently had a problem with the landing gear that my mechanic said he never heard of and that the odds were 100 to 1 that it would happen But it did To make it short and to the point was coming in for a landing and while on the downwind lowered
63. ce manual This will also enable you to use the wire number codes on the schematic to identify specific wires in the circuit The circuit is fairly simple Power for the green light comes from the cylinder head temperature and oil temperature circuit breaker This enables the green light to function with the gear motor circuit breaker popped The next item in the chain is the green light dimmer portion of the instrument light rheostat and switch With the instrument light switch on the resistor R1 is in series with the green light then the green light is dimmed for night operation R2 is a resistor that is in parallel with the green light The resistor provides current flow through the circuit when the light bulb is burnt out The resistor R2 is located in the center of the flasher box under the nose cowl PA 30 39 on the member where the voltage regulators are attached R2 is the center resistor The green light socket is insulated from the instrument paned with insulating washers If these break down the light will burn any time the master switch is on A chain of gear limit switches provides the ground for the green light ICS TIPS Chapter 7 Landing Gear and Brakes Page 101 of 103 BATTERY A A CYLINDER AND OIL TEMPERATURE NOSE WHEEL CIRCUIT BREAKER LIMIT SWITCH RIGHT GEAR DOWN LIGHT GEAR Es LIMIT SWITCH DIMMER CIRCUIT _ LEFT GEAR LIMIT SWITCH INSTRUMENT LIGHT REOSTAT SWITCH CEN
64. d out or pushed in Problem Open circuit breaker Solution replace Trouble shooting hint When gear fails to operate and circuit breaker is not popped put gear position lever in position opposite to the position of the gear and cycle the circuit breaker If motor runs momentarily probability is high that circuit breaker is bad If motor does not run at all probability is high that circuit breaker is OK TWIN GEAR MICROSWITCH WIRING I ve wanted to send you a note on the PA 30 landing gear microswitch wiring we had a broken wire on left main where the 4 wire bundle had to bend due to gear retraction VIZ ICS TIPS Chapter 7 Landing Gear and Brakes Page 16 of 103 EXTEAED REAR yen LEWN TEO L it Ama Burdi E lt enen o siku uwor a ee ABA Sum E IW SLAPA AE Go BENO IN yave BWUDLS My diagnosis of the basic problem The cable clamp at pivot arm if factory positioned holding cable about 1 1 2 away radius from pivot point The result has to be a large transverse motion of the bundle as the gear retracts My solution Reverse the position of the 4 bundle clamp on pivot arm as follows This reduces the transverse distance the clamp ergo bundle has to travel to about 1 4 more less Basically the clamp now rotates only instead of rotating and traveling installed all new micro switch wiring in new spaghetti splicing onto old wiring just inboard the wheel wells The new wires
65. d plane parked extend the manual gear arm and note where it is relative to the instrument panel On the earlier models with gear handle on top of the floor the distance will be less than 2 On the later models and twins it may be as much as 10 Don t take my word for it check your own plane If the gear is down but not locked it may land beautifully and collapse when you turn off of the runway Hope this prevents at least one gear up landing GEAR TRANSMISSION am writing this letter as a result of some recent experiences which we have had with our Comanche and its landing gear problems We have flown the plane for about 10 years and about 1 000 hours with no gear problems all of the time reading in the Flyer about people who were not so fortunate About nine months ago we began to experience occasional gear problems which we overcame by resetting the circuit breaker As the problem occurred more frequently we took the plane to our two nearest Piper dealer FBO s for repair Each installed a new motor and new bungees and a few other parts charged us between 400 and 500 and sent us on our way with no improvement in the situation In the meantime the problem became increasingly more difficult to handle and finally to the place where the gear wouldn t work at all In desperation we called ICS who advised us to take the problem to Bob Weber at Newton KS operating as Webco Aircraft To make a long story short we flew the airplane
66. d the outboard fixed roller Turn the adjusting nut to put some tension on the bungee Adjust as required to allow easy removal of the bungee roller retaining bolt on the gear arm Note the position of the washers for reinstallation Grasp the bungee and tool by the conduit and unscrew the fixed roller assembly Before taking the old bungee off the tool measure from one roller center to the other roller center Measurement needed for installation of the new bungee Turn the adjusting nut to relieve tension on the bungee and remove the tool Disassemble the fixed roller and reassemble with the new bungee Insert the tool in the bungee with the fixed roller on the conduit end and the pivot roller on the bolt end Now turn the adjusting nut so that the roller to roller measurement is the same as before removing the old bungee Now cut a hole in a piece of duct tape and insert the bolt of the fixed roller through the tape folding the tape back over the roller and bracket This holds the bolt in line with the tool to facilitate installation ICS TIPS Chapter 7 Landing Gear and Brakes Page 39 of 103 Le j3 la Threaded Rad Adjusting Nut Nut c w Washer TIM MLE Lat sth en Top View i TE Ya Conduit J hy a J i Side View You are now ready for the installation While looking outboard from the wheel well insert the bungee and tool into the wing The mounting hole for the fixed roller should be clearly
67. determine if nose gear down d Trade amber amp green light bulbs as bulb test If unable green light have tower visually inspect gear If any gear up or partially up anticipate collapse of malfunctioning gear Proceed to partial gear landing If gear stripes full travel and all gears appear down consider landing on centerline without attempting manual extension Avoid crosswinds Be alert for possible gear collapse If Gear Stripes Not Full Travel 1 Za 3 4 5 6 7 Reduce to 1 3Vsf with full flap Power for level flight Check Master switch NO and generator charging Reset breakers if necessary Reduce electrical load Check Landing gear motor and solenoid circuit breakers If either or both breakers popped move gear selector to OFF reset breakers and attempt gear down electrically while pushing on emergency extension handle to assist motor If unable stripes full travel consider placing gear selector down and forcibly holding breakers in not to exceed 8 seconds If available have co pilot push extension handle forward at the same time Repeat procedure if required after five minute cooling If stripes now full travel but no green light backtrack to Item 8 of first checklist and complete remainder If unable stripes full travel proceed with manual extension Manual Gear Extension Last Resort 1 2 3 4 Maintain 1 3Vsf Landing gear switch OFF Remove transmission cover amp pull motor releas
68. diately check their emergency gear release recently had a new gear motor and transmission installed When the electric system failed found the manual release to be impossible to use We even popped the rivets without moving the release The problem was eventually traced to defective parts furnished by Piper am surprised that no service bulletin or AD has been issued for this condition ED The slot that the motor release arm locks into was not true and once engaged it could not be removed He didn t mess up his Comanche The gear finally lowered electrically If you have ICS TIPS Chapter 7 Landing Gear and Brakes Page 14 of 103 replaced a transmission lately check it closely He tells me that you must see both parts together before you can notice the difference GEAR TRANSMISSION ASSEMBLY After a recent manual landing gear extension as a result of a discharged battery thought it was as well to take the entire motor and actuator assembly out for a closer look The log book never showed this item to be replaced or even worked on in the 2 000 hours of its existence And assume it has gone through at least 2 000 landing gear cycles in that time Once disassembled several things were readily apparent The main ball screw shaft was badly in need of new lubrication The worm gear reduction had grease but it had dried out and was caked on the sides and actually was doing little lubrication The actuator assembly was thoroughly washed
69. ds used to check the studs please call me Otherwise won t bore everyone with tedious details Another thing found during this was that one of the bushings did not have a chamfer to match the radius of the stud This is easily fixed but just one more thing to watch for Very special thanks to George Haddad owner and Loraine Fowler office manager of Hadco Inc 2420 Arnsler Street Torrance CA 90505 for all of their time and patience Another good shop for our members to deal with Tammy s Aviation Shop 310 635 1984 can take care of having parts tested if you wish ICS TIPS Chapter 7 Landing Gear and Brakes Page 71 of 103 GEAR WARNINGS Maurice Taylor When was the last time that you heard your gear warning horn If it isn t somewhat bothersome in the traffic patterns then it isn t adjusted properly or isn t working at all Testing this is required by your IA at annual inspection It s item 19 in the gear section for both the single and the twin Please believe me in too many cases this is not getting done Ask your IA at what MP the horn is set to blow You can be the best one to check this When in the air with the gear up ease the throttle or throttles back to 12 14 In Hg to be sure that horn blows remember that with the twin you have to have both throttles back have sent a device that made to a reliable company that when they get approval from the FAA that will have a warning in the head set and a flashing r
70. dvertises in the Flyer that they rebuild them Their phone number is 316 283 7929 NOSE GEAR DOOR WORN HINGES recently wrote you telling tribes people about all Jim Kinney my local FBO and fellow Comanche owner had done to improve our 5585P Little did know that a week or so later would be struggling to get my gear down by hand and seriously looking at the possibility of having to bring her in on the grass of my destination airport After almost 20 minutes of working the emergency lever back and forth with all my strength gear stuck half down and keeping the old bird in slow flight was able to break things loose and she popped down solidly with a big sigh of relief When landed it didn t take long to see that the front gear door was hanging loose from its front hinge and had jammed up against the gear the gear hub evidently having caught on the top edge of the door The picture below shows how the hinge had worn through over the years If you haven t had your hinges checked recently during your annuals oh yes we usually wiggle them around a bit you might want to take a look As you know the hinges curve up into a cowl channel where it is impossible to see their condition Piper still manufactures the hinges but with a steel bushing pressed into the hole Check Those Gear Door Hinges ICS TIPS Chapter 7 Landing Gear and Brakes Page 25 of 103 JAMMED GEAR EXTENSION Recently on departing Hinesville GA in a strong
71. e arm up and forward through full travel Extend insert on some models emergency handle and push forward full travel If unable extend lift gear by pulling rearward on handle Then push forward as hard and rapidly as possible Repeat procedure If unable extend push handle forward using all available force Use foot and leg pressure Bend handle if necessary If gears extend but no green light conduct gear warning circuitry check in Item 8 of first section If unable green light after circuitry check request tower visual inspection If all gears appear down and both rod end stripes are full travel proceed with landing Avoid cross winds Hold extension handle firmly forward with foot to prevent possible collapse on landing roll Disregard this item if Safety lock installed If unable extend all gears see Gear up or Partial gear landing procedures below ICS TIPS Chapter 7 Landing Gear and Brakes Page 94 of 103 Gear Up Landing 1 Declare emergency Fly to airport with emergency equipment and long runway into the wind Consider excess fuel burn off Declare souls on board Request emergency equipment Consider zero flaps landing at higher approach speed if runway permits Plan idle power touchdown Brief passengers on bracing positions and rapid exit 2 If two gears in op retract operative gear if possible Have tower confirm gear positions 3 Just before flare Fuel selector amp Master Switch OFF 4 At touchdown Ig
72. e green light and the horn Be sure you know at what power setting the horn blows and it should be 12 to 14 In Hg If it doesn t blow get it fixed DON T fly the aircraft if the horn is not working and adjusted properly If it doesn t annoy you when it comes on as you are slowing down in the traffic pattern then it isn t adjusted properly Most maintenance shops are far too casual in their attitude toward the horn adjustment If you land gear up it is your hard earned dollars which will go in the repairs 5 If the gear doesn t go down a Check all circuit breakers b With emergency door open select down Take note whether or not the transmission is trying to put the gear down If it is and you have a model with the exposed handle try helping it c If itis not trying at all and doesn t kick the circuit breaker back out then it will have to be put down with the emergency system 6 Todo this you must fly the airplane all the time Piper says the airspeed is not to be above 100 mph would reduce it to approximately 90 mph With the gear in the near full up position on a properly maintained Comanche it will fall to the full down position with the airspeed not above 90 mph But to be sure check for your green light and no horn For those with the exposed handle the red knob should be in the right place 7 Always keep in mind that with the gear disconnected there is NO down lock An exception to this is if you have the emergency extension s
73. e longer time Also in retrospect we should have measured battery voltage Next year will try for these extras to get a more precise working baseline During our disassembly and inspection process we found only one bushing and bolt in the nose gear out of tolerance and needing replacing We thought that pretty good for an airplane manufactured in December 1964 with 2 300 hours on the airframe During the reassembly we noted that there are several bearing surfaces which are not provided with grease fittings for on going lubrication On all of these we used a silicone based grease This material has several outstanding characteristics it is very slippery it absolutely protects against moisture and does not evaporate It is an ideal material for corrosion protection and maintains its lubricity to very low temperatures in addition to having about the best over all useful temperature range of any grease General Electric manufactures such a grease under the designation G 341 which complies with MIS 13041 Needless to say we were surprised and delighted to find our current drain lower after the gear mod than it had been before It was just about two amps lower all the way around except for the brief peak near the end of retraction where it was 15 amps lower This was a substantial improvement Our gear was not stiff In trying to account for this fortuitous development we had several thoughts It was at this point that we realized we should h
74. e of fatigue deformation stretching of the part either A call to ICS elicited this advice 1 They were all somewhat loose when they came from the factory and 2 don t place any part orders until you ve checked all the threads with an ANSI gauge We never got as far as the thread gauge An enterprising young mechanic had the idea to swap the left side link brace with the right one The left one was slightly loose too but serviceable Lo and behold when interchanged they both fit perfectly No side play no end play nothing Now this might not be worth taking up space in the Flyer if it were not for the cost of the part 553 Yup better than a half a thousand for a 61 long casting with threads on one end and a few holes on the other GEAR POSITION INDICATIONS am a registered Mechanical Engineer with an A amp P License enjoyed P K Roberts article on Comanche Landing Gear incidents believe that he failed to address one point that is left out of owner s manuals and even the AD on Comanche gear The point is How does the pilot know when the gear is down and locked if he has had an electrical failure ICS TIPS Chapter 7 Landing Gear and Brakes Page 41 of 103 believe that every Comanche driver should try a manual gear extension while on jacks This procedure should be repeated several times or until he or she is sure what it feels like when the gear locks down Also if you haven t done so with the gear down an
75. e they d fit under a Comanche wing and thought Why couldn t build my own So bought a pair and conjured up a simple way for me to construct an aircraft jack using materials was familiar with calling on my carpentry mentality started with a plywood base and figured I d brace the jack with four legs made of 3 4 electrical conduit fastened to a collar around the jack The collar would be fashioned from a steel fence part found at a building supply store while buying the plywood and conduit needed Warning The next part is dry technical stuff Skip the next four paragraphs if making your own jacks is not your cup of tea took the jacks to a machine shop and had the tops cut flush and machined with a recess to fit the jack points under the wings Now was ready to see if my concoction would go together cut the plywood into two 22 squares and drilled 1 4 holes in the corners 17 3 4 apart Then cut the conduit into 24 1 2 lengths 8 pieces and flattened each end in a vise The ends were then drilled with 1 4 holes and bent to fit between the base and the collar Each collar was drilled with four 1 4 holes spaced 90 degrees apart For each jack the conduit legs were fastened to the base using flat head 1 4 bolts through large washers on the bottom Next the jack was placed in position with the base of the jack in the center of the plywood base Flat head 1 4 bolts were inserted in the collar with the threads stick
76. e time GEAR SYSTEM TESTS It seems to me that articles have read give the impression to those unfamiliar with this fine airplane that there are serious faults in the design or construction of the landing gear system The basis for this is the frequent accident reports in which the landing gear has failed to extend or collapsed A number of accidents have been experienced by extending the landing gear at the limit speed or over In most of these cases the pilot may have noticed the nose gear in the mirror on the left engine cowling and assumed it to be fully extended A warning gear horn should have been ICS TIPS Chapter 7 Landing Gear and Brakes Page 47 of 103 sounding and no green light would have been obtained The reason the gear did not fully extend was that the wind load on the nose gear was greater than the electrical circuit breaker protection on the landing gear motor If such as the above is experienced first check the circuit breaker of the landing gear motor second check the green light for operation by exchanging the gear up light and third check for horn operation There should by no horn but an in air check can be obtained by throttle closing with gear up The horn is found not to be operating on a lot of aircraft that have worked on and most of the time the horn is at fault due to age dirt lack of use etc It is important and there is an easy way to check it while on the ground First pull the circui
77. e unless you are really adept at doing this task on the ground with the plane on jacks Although realize that other things can go wrong with this mechanism have encountered two particular problems in my twin Comanche emergency gear release that think ICS members should be aware of have found both situations bent links and a missing cotter key clevis pin on the emergency release arm ICS TIPS Chapter 7 Landing Gear and Brakes Page 64 of 103 Clevis amp Cotter Key Release Tube INSPECTION 1 The next time you get in your Comanche pull up the emergency gear extension door in the floor and look at two things the links attached to the red emergency gear release arm and the clevis pins which hold the release arm assembly on the drive shaft Inspect the release arm assembly carefully This assembly rides on a bushing that encircles the tubular drive shaft and is held on by means of two small clevis pins There should be a small flat washer and a cotter key on both of the pins If either cotter key is missing carefully replace the washer and insert a new cotter key without pushing on the clevis If you push it into the tube it will cause you great inconvenience If the gear is operated with the cotter key missing the clevis pin can fall into the tube and jam the landing gear in any position Next inspect the two links attached to the red arm to see if they are parallel and straight when viewed from above If they are bo
78. ecurity system either factory installed some did or added later Gear will stay down because it is over center and this is so only when your gear has been properly adjusted Putting the gear down by this method is an emergency method and always treat it as such And there is one other point which still crops up at regular intervals after all these years do remember to put the gear down in the first place FAILED NOSE GEAR PUSH PULL ROD ASSEMBLY Hubert Wren ICS 08002 Out at Peterborough Airport the preflight went smoothly Level at 2 600 ft we decided to head for Lindsay which was only 22 miles to the northwest When we arrived in the traffic pattern couldn t get the gear down no matter what did and was forced to land gear up The actual cause lay in the forward belly of the airframe One of the end fittings on the push pull rod assembly part 21109 00 had separated because of a poor weld effectively disconnecting the nose gear from the extension retraction mechanism Thanks to Maurice Taylor we found out that a Piper Service Letter SL 546A March 1970 addressed the problem and prescribed a simple solution Using this information Airtech remanufactured the rod to the later design That still left the puzzle as to why had a green light in the cockpit to indicate gear down and locked Most retracts have a green light for each gear leg but Piper chose to use only one on the Comanche with the limit switches for each gear
79. ed help help is as close as a phone call away especially with a cell phone on board It is funny after my initial reaction didn t feel pressure at all knew had a problem but also had two hours of fuel remaining a number of very long runways nearby and someone to help me resolve the problem Follow Your Check List slowed the aircraft down to the recommended speed executed the check list exactly as stated with my passenger s help pushing on the gear extension bar the gear fell easily into position had a green gear down light indicating a successful extension But now there was a question Green light or not was the gear actually locked down called the tower again and asked for a flyby to verify that the gear looked extended Was a flyby worth the risk One theory is that no one on the ground will really be able to tell if the gear is actually locked down and the risk of low and slow flight isn t worth it Because the three gear switches are wired in series on the Comanche if all three switches are working correctly then a green light indicates that all three gear are down But if you are careful as was there is nothing that can be hurt by a flyby But maybe nothing gained After the flyby the tower responded that the gear all looked down and cleared me to land on runway 12L At this point believe showed real common sense First knew didn t need to rush to get on the ground and second felt that landing on
80. ed in flight during retraction and even extension Three days later found a totally dead battery and replaced it Result No gear problems In the course of the problem at one point attempted to lower the gear manually and could not though followed the procedures in the manual later discovered while using the manual system with the airplane on jacks that it is necessary to press the lever as though trying to further raise the gear to release tension before releasing the gear for lowering When encountering a popping gear circuit breaker check for a bad battery This may be the real problem since low voltage apparently increases amperage I am told MAIN GEAR BOLT FREEZE UP In spite of supposedly oilite bushings in hinge end of scissor link had a main gear bolt freeze up and shear Had to use hammer to free the bolt noticed pull on takeoff from paved surface but nothing else Due to short distance to next landing did not retract gear Next landing and takeoff on turf were both normal Apparently gear turned and did not retract on second take off as found breaker popped before next landing Gear went down OK after breaker pushed in but on rollout on turf did a 135 degree ground loop but suffered no damage LOW BATTERY EFFECT ON LANDING GEAR was interested in your recent account describing gear problems related to a weak battery and particularly the remark that low voltage apparently increases amperage While it
81. ed light on the instrument panel along with the regular gear horn when the MP is lowered to 12 14 In Hg Remember that the horn is the back up or second method to tell if the gear is down and over center As have said so many times before if either the horn or green light is not working properly don t fly the airplane until both are working ELIMINATING THE POPPING OF THE GEAR MOTOR CIRCUIT BREAKER Warren Cermak ICS 01686 For several years had been having trouble popping the circuit breaker on my 250 Comanche when retracting the gear during cold weather Living in the northern cold wintry climate resetting the CB every time raised the gear was not a thing that had wanted to do The problem only occurred when the gear was being raised at the end of the gear up travel developed the habit of assisting the gear up by using the emergency extension handle This usually avoided popping the breaker To make a long story short a lot of time and effort and new parts went into the quest to try to eliminate this problem It was finally solved by Bob Weber at Webco who replaced the push pull cables These cables had passed a torque test earlier but this was done with the aircraft on jacks and without the air resistance one would encounter in flight This resistance in addition to cables that were marginally sticking was enough to cause the circuit breaker to pop when the gear were lowered P S Regarding Mr Cermak s gear problems we beli
82. er 688 have more expensive switches and cost more as for the singles recommend every Comanche owner call Matt Kurke toll free at 877 643 6944 or look at his WebSite at www comanchegear com and learn about this improvement would combine his system with the Webco holdout brackets and you will enjoy safety and peace of mind This is a real improvement over the Piper design THE CASE OF THE WOBBLING COUPLING Al Bieck ICS 02171 Shortly after we bought our 1960 PA24 250 in 1975 discovered that the landing gear motor had a tendency to get quite hot Closer inspection of the Dura transmission revealed excessive endplay and badly worn teeth on the driven gear inside So replaced the motor and installed a new Dukes transmission A new coupling Piper part number 751 517 was also installed between motor and transmission ICS TIPS Chapter 7 Landing Gear and Brakes Page 90 of 103 During the intervening years the transmission was repacked with Dukes 4 lubricant at regular intervals while the motor and motor brake were inspected and checked for proper operation during and between annual inspections Two weeks ago as retracted the gear after takeoff the amber UP light illuminated then extinguished came on again went off came on again staying illuminated for about two seconds each time until placed the landing gear selector switch in the center OFF position While returning to the airport thought that the UP limit switch
83. er 7 Landing Gear and Brakes Page 37 of 103 i 2 3 4 s 4 b RELEASE anu MELCASE TUBL TRANSMISSION SCREW NUT TRANSMISSION SCREW ROLL Pin STOP TRANS 98100 TAANSMISSION COVER TRANSMISSION GASKET SCREW OCARING COUPLING BEARING RETAINER PLATE DURA TRANS ONLY scatw LINE TAANSMISSION RETRACT SPRING PA 14 100 AND PA 14 230 SERIAL NOS 24 1 TO 24 3337 TRANSMISSION RETRACT SPRING PA 14 180 AMD PA 24 230 SERIAL BLS 24 3538 And UP PA 14 260 ANN PA 24 800 16 7 18 hi 11 12 23 Mu MOTOR BRAKE ASSEMOLY CARL YI BRAKE SOLENOIO MOTOR BRAKE DISC TENSION SPRING MOTOR BRAKE ASSEMOLY LATE RAKE SOLENOID DRAKT SUPPORT ARM TRANSMISSION MOTOR TRANSMISSION ORIVE SHAFT RETRACT SPRINGA BRACKET These notes appear in the Handling and Service section of the maintenance manual Since removal disassembly etc of the transmission should be performed by qualified maintenance personnel make sure your mechanic or shop is aware of these notes STRUT MAINTENANCE Keep your struts clean The enemy of strut seals is dirt When you check the fuel sumps for water save the gas you drained out and use it to clean the struts with a soft rag then spray ICS TIPS Chapter 7 Landing Gear and Brakes Page 38 of 103 Teflon or silicon on them and rub it around all over the strut Of course jacking the aircraft will let you do the full strut length Also take a strip of old T shirt materia
84. er to get the gear down by the emergency method and then to turn the transmission coupling by hand until the release mechanism on the jack screw has moved back far enough to be hooked up again This would provide the down lock protection of a normal gear extension and avoid depending on the drag links to remain in the over center position after landing and when taxiing The February Flyer was very informative After reading the article by Glen Plymate A Weak Link checked the torque of the clevis in our aircraft With the torque wrench set to 30 ft lbs the clevis did not budge Thanks for the tip MAKING THE LANDING GEAR ADJUSTMENTS Cecil Wachsman ICS 02041 just finished reading the Special Edition of the February Comanche FLYER for the Landing Gear All articles were very worthwhile and very knowledgeable myself being an A amp P mechanic found the articles extremely interesting However found a couple of items missing however It seems that not many mechanics know about the gear adjustments The adjustments are never mentioned and this is so important to the maintenance of our Comanche Airplanes What is not mentioned is the up limits adjustment of the gear and the door They go hand in hand The reason it is so important If done by the book the gear and doors won t move up and down while in flight and encountering turbulence therefore wearing the bushings and affected parts ICS TIPS Chapter 7 Landing Gear and Bra
85. ere listening closely and hearing about many people having troubles after the gear mod had been done This made us more apprehensive then ever So when our turn came we had made arrangements to work with an excellent A amp P Al mechanic His name is Peter V Wolfe have a degree in Mechanical Engineering and am a Registered Engineer Pete and got our heads together about this gear mod and came up with a couple of new ideas which we with Piper Aircraft Corporation The first idea was to monitor the total energy flow in the gear system both before and after the mod This arose from Bill Black s information that it sounded like many people were having a stiff system after the mod was done and tripping circuit breakers So the first thing Pete and did was to jack up the plane and put a DC ammeter at the battery turn off everything else and operate the gear The current drain shown on the ammeter is a direct measure of the total energy required to operate the system stiffness included Here is what we found ICS TIPS Chapter 7 Landing Gear and Brakes Page 21 of 103 Note that the time is approximate In retrospect wish we had had a recording ammeter then the time scale would be precise With an accurate time we would have one additional factor measuring total energy For instance with a stiff gear the gear motor will be more heavily loaded and for a given battery voltage the motor will run more slowly and the operations will tak
86. es Page 70 of 103 learned a long time ago that if you don t know very much about something go ahead very carefully so here go Regarding the landing gear studs inspection of we had a few reports of the studs being inspected using Type fluorescent liquid Penetrant to check for cracks then for whatever reason had them checked again using the magnetic particle inspection method This indicated a crack where the first method did not What have learned from a technician for a major airline and from an Aeronautical University is if the part to be tested had been bead blasted or wire brushed this will probably prevent you from finding a crack using the liquid Penetrant Clean the part using something like Varsol then inspect it MORE ON THE LANDING GEAR SIDE BRACE STUD Bill Farmer ICS 08995 On the advice of Maurice Taylor long before the AD was published had inspected the studs in Harley s PA 30 using the Dye Penetrant Type Fluorescent and Type 2 Dye Penetrant procedures Neither showed any signs of cracking then or when did it again for the AD A friend had the studs from his 250 Magnafluxed by Hadco Inc a local FAA approved test facility and both were rejected for cracks This will make a good test piece thought and proceeded to give them the works with everything have access to which is almost all field test equipment To my dismay could not find the crack in one of the reject studs I have a level one certification
87. eve that the angle of the main gear door when in transition and its combination with the air pressure at the higher gear extension speed range is causing up pressure on the main gear conduit even as it is being extended or pushed down This is putting the inner cable of the conduit in compression and pushing it against the back side of the inner casing Since this is not the normal path any dirt or grime which has built up over the years or a bad area which normally is not contacted is causing the excessive drag In Mr Cermak s situation we were thrown at first because it passed the torque test as described in the service manual when on jacks Everything appeared fine We realized that the only thing missing was the air pressure on the aircraft Without the air pressure of flight the weight of the gear is helping to pull the gear conduit inner wire down After removing the conduits we found that when placed in the same position as in the aircraft they were very difficult to move FROM THE TOOL BOX OF MAURICE TAYLOR Just another reminder is the gear down It is my belief that the check list is not being used every time Does the gear horn work properly and at the proper M P 12 to 14 In Hg If the horn ICS TIPS Chapter 7 Landing Gear and Brakes Page 72 of 103 doesn t bother you when you are getting slowed down in the pattern then it s most likely not adjusted properly Does the green light work properly Remember the horn is a back up fo
88. f 103 mounting bolts When the gear is retracted the housing will be in the clear inside the wheel well The change was made about three or four years ago and probably took about 3 to 4 hours all together The results You will notice lots less drag when the gear is lowered for landing so assume there is less drag on takeoff With the gear retracted and the brake housing on the inside there should be less drag in level flight Since the brake housing stuck straight out into the airstream can only conclude that there is some real benefit there From the appearance standpoint it does make the gear look more uptown and less like a part from the bicycle store but how many people go around looking at the main gear of the Comanche feel that the changeover has helped top speed in level flight some 2 to 3 mph perhaps but wouldn t want to argue that point with some sharpshooter Another benefit is that you end up with two used forks They clean up nicely and can be stored out of the way and can be used on the nose gear some day after those holes you put the tow bar in wear out In fact you will have a lifetime supply Don t count on selling them ED Make sure that the modification is properly documented and signed off POPPED GEAR CIRCUIT BREAKERS Several different causes have been described for landing gear retraction problems Most of the problems manifest themselves by the gear motor breaker popping just as the gear reaches the f
89. feeling for any roughness Better yet disassemble unit and visually check the screw and balls ICS TIPS Chapter 7 Landing Gear and Brakes Page 43 of 103 GEAR WARNING HORN SYSTEM From what am hearing at the seminars as well as the calls receive there are just too many gear up landings There are certain items in your aircraft which can be a Go No Go situation If any part of the landing gear warning system is not working in my opinion this is a No Go situation There are certain things you must know are in working condition 1 Does the gear warning horn work properly 2 Can you hear it 3 Is the throttle switch es adjusted correctly to actuate the horn at approximately 12 to 14 In Hg 4 Does the green light work properly Your Al at the annual inspection should not return the aircraft to service until these items have been checked and found to be in working order and properly adjusted know that this is not being done in too many cases In regard to item 2 many of you are now using the large headset to effectively block out the engine noise Just remember it also blocks out the noise of the horn Correct this potential hazard by getting the horn into the audio system or install a light on the panel in a conspicuous position to come on or to flash when the horn is activated at 12 to 14 In Hg This won t help if the throttle switch es are not adjusted properly The warning system is well designed The horn and ligh
90. g checklist We should remember that the left torque arm controls both the right main gear and the nose gear and the right torque arm controls the left main gear We do not believe landing on the left main gear alone is feasible due to loss of nose wheel steering and that gear should be retracted if possible and the aircraft landed gear up If the stripes are not full travel then we have a different problem and item 6 directs us to proceed directly to Gear stripes not full travel That checklist is an optional insert and you may be directed to return to this section For now we will assume that item 6 does not apply Assuming the motor drive shaft moved normally and the transmission appeared normal we believe it is now safe to recycle the gear in step 7 in an attempt to get the light green followed by a gear warning circuitry check in step 8 A silent horn is confirmation even without a green light that the nose gear is locked and gives us useful information as to what to expect on landing Swapping bulbs on some aircraft isn t easy If you have a plywood cover on the panel it must be removed which requires a midget alien wrench for the DG knobs and a Phillips screwdriver for the panel itself Got those on board We strongly recommend a tower inspection anytime we do not have a green light Gear down probability is extremely high if the stripes are full travel but there is an exception If a rod end gear cable breaks at the gear during ex
91. h B shows the bungee roller crank in the correct position when the gear is up with an arrow showing the direction of rotation when the gear is cycled down PiveTs FIXED e TO STRUCTURE Fixeo Rouer SUNGEE TELEMLEX Drive CADLE LR A eK S N At AC E yo 5 gt get ta Bu NG EE Rewer CRANK D RAG St RUT CENTIRE Assy DRAG LINK AvovstaBie SKETCH A Looking Forward Left Wing Gear Down Bungee Crank Correctly Installed Notice in sketches A and B that the bungee tension is increased until it goes over geometric center approximately 45 point of travel then it begins to assist the gear in its direction of travel either up or down ICS TIPS Chapter 7 Landing Gear and Brakes Page 19 of 103 SKETCH B Looking Forward Left Wing Gear Up Bungee Crank Correctly Installed Sketch C Looking Forward Left Wing Gear Down Bungee Crank Incorrectly Installed Now recommend that Dick remove the under wing bungee cord access cover of his Comanche and check to see that the bungee roller crank is positioned as shown in Sketch A If it is positioned as shown in Sketch C he should get it into his favorite Comanche mechanic without delay because when new bungees are installed he may get an open circuit breaker when he tries to cycle the gear down on the first landing attempt after new bungees are installed know of three such incidents including my own little sweetheart N6734P
92. h to Memphis the gear failed to extend electrically From experience manual extension does not work above 95 MPH slowed to 85 and got it down On the jacks ran the gear five times with no problems After a thorough inspection decided to fly home After takeoff the gear almost completed the up cycle before the breaker popped After a few minutes in the air reset the breaker and the gear completed the cycle On lowering the gear at Murfreesboro it worked fine put the aircraft on jacks and totally went through the system including a rebuilt gear transmission from very cooperative Bob Weber at Newton KS Although the motor was new decided to go through it As separated the motor a piece of metal fell out Upon close examination it was evident that the small chunk of metal would get between the armature and field jamming the motor Also the bearings were totally without lubrication Since that experience my gear really works fine I ve also re rigged the gear as per the maintenance manual which think a thorough re rigging job is highly recommended It s time consuming but worth it for peace of mind and especially the limits on the transmission ICS TIPS Chapter 7 Landing Gear and Brakes Page 45 of 103 GEAR BUNGEE ARMS Headquarters has advised me that they have received several inquiries about the bungee arms cracking or breaking The bungee arms which are in the 180 s and 250 s are part 20846 00 for the left and 2
93. had a natural curl to them as they had come off the supply reel took advantage of this and flowed the new bundle in an appropriate way to minimize bending In actual operation the wires now curl they don t bend at all have looked at the wiring on many Comanches and all seem to have a definite kink in the bundle at the bend point am convinced that this is the definitive fix for eliminating the possibility of broken wiring due to gear retraction ICS TIPS Chapter 7 Landing Gear and Brakes Page 17 of 103 Raveextev Met WING gt SAN w aino SAL cueu TO GH BVVWP_rd NRE yin FeoKine FROM w Ec WELL TOWA O0KHAAAKA GEAR BUNGEE ARMS Had the March 1981 issue in my briefcase when left Lockheed Burbank on a business trip last week would have read Piper Comanche Landing Gear Inspections The first two paragraphs were right on He recognizes a bunch of bureaucratic paper work issued to presumably cure a non existent problem When he said it took both he and his wife to manually extend the gear with their feet against the handle an alarm bell went off in my mind it s time for this supportive old engineer to open up First let s clear up some key points i 2 The toggles are not toggles They are called drag struts in our trade The drag struts on the mains of a Comanche are assisted to both the full up and down and locked positions by the bungee cords in the wings The nose gear d
94. had been installed 34 years ago in compliance with AD ICS TIPS Chapter 7 Landing Gear and Brakes Page 88 of 103 65 25 03 and Piper Service Letter No 445 dated April 21 1965 An earlier Service Letter No 336 also done called for a heat treated clevis marked HT The 1000 hour gear inspection only recently done does not call for the clevis torque to be checked It looked okay at that time and the AD for the clevis had been complied with and was not recurring Everything was legal But the drag link clevis was loose and it was difficult to detect It was an unsafe condition How long had it been loose don t have a clue I ve had the airplane for 21 years and as far as know the clevis torque had never been checked A more important question is how long would it have gone before breaking Thoughts raced through my mind about what could happen to my brand new prop and having to tear into my freshly rebuilt O 540 if the clevis broke not to mention the sheet metal repairs But perish the thoughts We had to get on with fixing that loose clevis The clevis is shimmed with one or more shims between the clevis and drag link to give it the proper spacing for connection with the push pull rod On the early PA 24 s the clevis is threaded into the drag link and must have a torque of 13 to 40 foot pounds when it is aligned with the drag link It is then held in place by a drag link clevis reinforcement bracket as shown in SL 445 App
95. haneteninas ueinanaua AE e aa iaa A 83 ICS TIPS Chapter 7 Landing Gear and Brakes Page 2 of 103 COMANCHE ACCIDENT INCIDENTS STATISTICS May 1 1987 to Dec 31 1999 85 RoR A HOWA DIDAIT ARTO E tinct chcodaichtinegabencteaeaatnateans doit 86 AM AK EIN aiii 88 WIRING TO LIMIT SWITCH COMANCHE LANDING GEAR oo eee cence eeeeeeeeeeneneeees 89 THE CASE OF THE WOBBLING COUPLING c omoreianoninna irc 90 MAKING THE LANDING GEAR ADJUSTMENTS 0 eee e een e ee rteee eee enneeeeeee 91 JAMMED GEAR EXTENSION aa caia ninio siiedueinatsteetedenccoantust A TA La Ae danger dada caos 92 ABNORMAL GEAR OPERATION ona iia 93 ABNORMAL GEAR OPERATION CHECKLIST sectiroriassoocatrnee rat 93 ABNORMAL GEAR OPERATION i iii di cc 95 GEAR DOWN LIGHT sisi A a AA E AAA 101 ICS TIPS Chapter 7 Landing Gear and Brakes Page 3 of 103 GEAR WARNING HORN Here is a bit of trivia for your next hangar flying session with a bunch of PA 30 drivers discovered it one day while examining the landing gear schematic Assume you extend the landing gear It appears to go down but you do not get a green light If you retard both throttles to idle and the gear horn does not blow it means that the nose wheel is down and locked However no information on the state of the mains is conveyed Conversely if the horn does blow it indicates that the nose wheel is not locked and the mains are still in an unknown state All of this obviously assumes th
96. he as posted by the FAA It soon became evident that the majority of accidents are related to the landing gear Descriptions like aircraft landed gear up gear collapsed on landing and the like kept appearing at an alarming rate therefore stretched my classification of the accidents incidents to Gear and others with fatal as a sub classification included in the above Now to the figures During the 32 month period from May 1st 1997 to December 31st 1999 there were 143 Comanche accidents incidents in the USA of which 83 58 were related to the landing gear and 60 42 to other causes 13 9 were fatal The annual average number of accident is hence 54 out of which 31 are related to the gear and 23 are due to other causes The obvious observation is that by far and large the inappropriate operation and or maintenance of the gear are the major causes of accidents incidents of the Comanche fleet In order to corroborate this conclusion looked again in the Comanche Safety Review conducted for the ICS by the AOPA Air Safety Foundation This document cited 440 accidents for the 11 ICS TIPS Chapter 7 Landing Gear and Brakes Page 85 of 103 years period of 1982 1992 or a yearly average of 44 During the 32 months of my survey we seem to be above this average but it is not so A further study of the AOPA ASF document shows that during the period of 11 years it counts 33 gear related accidents The average annual rate
97. he all consuming period piece that bought to fly and maintain as a hobby Thanks to years of oversight and neglect had to remove the abused pieces and suffer an inordinate assault on my cash flow for the machinists spent five hours setting up the bellcrank and five minutes to do the actual cutting because of the need for the bushing rollers to follow ICS TIPS Chapter 7 Landing Gear and Brakes Page 31 of 103 both cam profiles simultaneously without binding Also spent a couple hours on a lathe cutting out new oversize bushings from 4130 steel bar stock Considering the need for repeated removal and installation of the offending pieces and the time consumed obtaining a field approval of the repair from the FAA felt this whole exercise could have been much less expensive had a whole series of mechanics more carefully inspected the nose steering parts over the years How much simpler it would have been had the bushings been routinely inspected and replaced for the steering bellcrank itself would not have been damaged necessitating expensive repair or replacement 1 would guess that more than half the Comanches and Twin Comanches still in service have suffered similar wear and neglect These parts incidentally are common to all PA 24 PA 30 and PA 39 airplanes Curiously the steering bellcrank was stamped Piper 21687 while the parts book calls out P N 21768 00 A Malfunction or Defect Report FAA Form 8010 4 has bee
98. he arms in stock due to the number we are finding that are cracked The condition could get so bad that it could release the gear and let it dangle as the shaft of this arm is what the gear rides on The newer arms have thicker walls even though they carry the same Piper part number ICS TIPS Chapter 7 Landing Gear and Brakes Page 33 of 103 really question the FAA s decision of bushings being the culprit of gear up problems rather suspect the gear transmission and this gear arm to be the main problem ICS TIPS Chapter 7 Landing Gear and Brakes Page 34 of 103 GEAR FAILURE JAMMED WHEEL WELL LINER The enclosed excerpt from the Transport Canada circular Maintainer may be of interest A few years ago during an inspection found that one of the attachment screws holding the starboard wheel well liner in place was missing causing the liner to vibrate and crack Checking the liners at least once in a while might be a good item to add to the walk around making it a crawl around It was a beautiful weekend ideal for a fishing trip but they never got there En route the pilot found he couldn t lower his gear by normal or emergency methods After several attempts and reference to the emergency checklist he elected to return to his point of departure at a major airport On the return flight he made several more unsuccessful attempts to lower the gear and then made a wheels up landing A section of the wheel well
99. he cylinder pistons are moving out and the retract cylinder is being pulled into position The tires should roll easily when the brakes are released this is the reason for the space between the washer and the end of the retract cylinder hope this procedure will help some Comanche owners who have always had sticky brakes ICS TIPS Chapter 7 Landing Gear and Brakes Page 59 of 103 1 BRAKE ASSEMBLY 10 WASHER 2 BACK PLATE 21 NUT 3 BACK PLATE LINING 22 BOLT 4 RIVET 23 WASHER s i 5 SPACER 24 NUT s n an 6 PRESSURE PLATE LINING 25 WASHER k a 3 PLATE u a CYLINDER u i 4 a Diagram 1 7 Interface here Preventing Pad from Contacting Disc Squarely FIGURE 6 28 BRAKE ASSEMBLY CLEVELAND PA24 180 and PA24 250 Serial Numbers 24 1 to 24 3295 BUNGEE ARM CRACKS Maurice Taylor Technical Director In the list of FAA Malfunction and Defect reports which Headquarters sends on to me one of them pertained to the bungee arms A mechanic had removed thin walled bungee arms and found them cracked and these were replaced with new thin walled arms assume the crack was at the point shown in the drawing below The thin walled arms were found only in the 180 s and 250 s The thin walled is 0 062 and the heavy walled is 0 125 as found in the rest of the Comanche fleet am puzzled about the thin wall replacement as back in the mid 80 s if you ordered the proper part number from the parts book for a 18
100. he part The part being aluminum protected by the insert bearing can be easily ruined by this occurrence As usual an AD can do more harm than good than was originally present Next came the realization that for some reason Piper did not see fit to provide a grease fitting for the Bolt bearing that attaches the draglink to the side brace support fitting This joint both rotates and swivels during gear operation and would seem to be as important a point to maintain lube as any of those with grease fittings Perhaps Maurice and or Piper can say why it was omitted Activity provides plenty of clearance for a fitting ED ICS advises that PN 20829 00 new production now has the extra grease fitting At any rate owners would do well to insure any bearing bushing replacement is done with the required lube hole and correctly reamed GEAR TRANSMISSION Here is an item have never seen addressed in the Flyer or Tips When servicing the gear box and actuating ball screw check the 1 8 steel balls have found the balls rough and some of them flat or broken in half On one plane that had just been repaired after a gear up landing and checked out on jacks it failed on the test flight necessitating the use of the emergency system The cause was found to be a damaged ball on the ball screw have checked the steel balls on a N6286P and found the same problem beginning to develop This problem can be checked by rotating the sleeve by hand
101. he pilot under Part 43 If so would appreciate your authorization so that can make reference to same in making log entries in continuing compliance with Part B of this AD Reply from Chief Engineering amp Manufacturing Branch AEA 210 We have reviewed your subject inquiry which was forwarded to us by our Southern Region for reply It will be acceptable for you as a pilot to perform the yearly repetitive inspections of the bungee cords called for by the subject AD and make the required logbook entries However the 500 hour inspection can be performed by an appropriately certificated person or shop ICS TIPS Chapter 7 Landing Gear and Brakes Page 4 of 103 Raymond J Borowski ED The last sentence should read can only be performed by an appropriately certified person or shop GEAR FAILURE MISALIGNED ALIGNER When was the last time you checked your aligner assembly If you ve been flying around in your beautiful Comanche and don t even know what one is now is the time to find out and check it out If you are planning to buy that creampuff Comanche that s been hangared since new and only been flown on Sundays by that little ole person in tennis shoes please disregard the beer cans in the luggage compartment then you ought to check out the aligner assembly The aligner assembly is a Y shaped channel about six inches long on the rear side of the nose gear oleo up near the top where the oleo is pumped up If you fo
102. he transmission thoroughly repacked it with MIL G 21387 grease Aeroshell No 7 meets this spec According to the maintenance manual this grease and grease meeting MIL G 7118 are the only approved lubricants for the Dura transmission DURA transmission with cover removed and old grease washed away ICS TIPS Chapter 7 Landing Gear and Brakes Page 35 of 103 Only Dukes No 4 grease is approved for the transmission manufactured by Dukes Again no substitutes are permitted Ten years ago when we bought our 250 C FZZV one of the first things did was to place the aircraft on jacks to check the landing gear wiring emergency release squat switch etc and to lubricate in accordance with the maintenance manual also pulled out the transmission and opened it up found exactly the same condition as that encountered recently replaced the transmission in our 250 back in 1977 with a Dukes unit which think is a better engineered transmission Are you depending on worn teeth like this to raise and lower your landing gear Note the irregular stepped appearance of the teeth My point is that am convinced that there are a lot of Comanches flying around with a transmission that hasn t been serviced for years possibly running dry and wearing out those teeth which could eventually strip think we all have gotten the message about the importance of changing bungees regularly and it is time to pay more attention to another
103. hem on a 250 due to cracks A good philosophy at this point is to replace anything that s even questionable We re fortunate to have Bob Weber s WEBCO for support He has just about any pan including bushings and bolts that you re likely to need for this operation OK so we ve got all the parts cleaned necessary bushings replaced and new parts ready to be re assembled and installed into your nice clean freshly painted wheel well Essentially this operation is a reversal of what you just finished do the assembly very carefully hand lubricating each movable part and then filling the lube channel with the lube gun They go together nice and smoothly now that they re clean and lubed If you removed the strut it needs to be replaced first followed by the drag links swivel pins and over center springs Then comes the new wiring you did order it in didn t you and adjustment ICS TIPS Chapter 7 Landing Gear and Brakes Page 79 of 103 The gear adjustment is naturally very critical that it be done correctly in accordance with the manual First check the preload on the push pull cables Then make sure that you hear one clunk when the gear is lowered with the emergency extension handle Following this head for the electrical Hook up your new wiring you did order it in didn t you and mount and adjust your switches Recheck for proper light indications and check retraction force with a torque wrench as described in the shop manual If
104. his appears to be a simple logical and low cost solution to the problem To duplicate this system one wire is run from the gear horn switch on the throttle up through the left windshield corner post into the overhead panel containing the cabin speaker and overhead lights ICS TIPS Chapter 7 Landing Gear and Brakes Page 44 of 103 Radio Shack sells a solid state Piezo type horn for just under ten dollars that operates on 12 volts weights about 1 1 2 ounces and is small enough to fit into the plastic shroud that covers the cabin speaker The wire from the throttle gear horn switch is attached to the red wire on the horn and the black wire on the horn is attached to ground The horn has two mounting holes and can be mounted directly to the plastic shroud This small lightweight horn puts out in excess of 100 decibels of sound A slotted cover allows you to reduce the sound level if needed With your best headset on and with the tower talking to you you will not miss the sound of the gear horn left the original horn as installed and consider the new horn as a redundant system The current drain is negligible the weight is negligible and the cost is very reasonable The installation took approximately one hour of labor The result is a gear warning horn that does the job TIRE TUBES Look out for bad tubes bought new tires tubes from Desser Tire and Rubber Company in California in July 1986 The left main went flat while parked in hang
105. hs and began circling Since there were high mountains only a few miles to the east devoted 80 of my time to flying the aircraft and 20 to resolving the problem Had been on an instrument approach in IMC would have notified the controller of the problem and asked for a clearance to depart to VFR conditions or to a holding pattern where could take as much time as necessary to resolve the problem ICS TIPS Chapter 7 Landing Gear and Brakes Page 83 of 103 Use Your Resources Luckily was not alone Although not a pilot my passenger Jon was an experienced Navy Air crewman and isn t prone to nerves verbally set the priorities would fly the aircraft as my primary responsibility and Jon would hold a flashlight and read the emergency gear extension check list With Jon s assistance would execute the checklist one step at a time Had been alone would have done exactly the same thing The only difference is that it would have taken me longer to fly read the check list and execute the items on the check list was over fairly dark landscape and the only outside references were the lights of San Jose to the west knew that was in a situation where could either lose outside reference when turning to the east or even accidentally fly into the mountains had another card up my sleeve Then as now carry both Maurice Taylor s phone number and the number of my A amp P with me when fly On the oft chance that ever ne
106. ibility exists for the roller to jump over the edge of the aligner Y at some unexpected time during simultaneous heavy rudder peddle pressure and gear retraction At your next annual inspection you can watch the aligner at work but it s not too healthy to try to watch the action while in flight it s kinda windy and you might catch pneumonia Checkout your aligner assembly and have it straightened if necessary It might save you some loot Notable Quote There s nothing as useless to a pilot as the runway behind or the altitude above ED Or air in your fuel tank BRAKES After much work on brakes with no luck called Lock Haven and found somebody there who knew what was the matter On early models S N 3295 and below the brakes have a self adjust feature which works on a single screw on each brake When the bushing gets corroded it seizes within the housing Clean it thoroughly and oil it and it will work much better JAMMED GEAR RETRACTION The tribe may be interested in my solution to a gear malfunction problem My Comanche experienced gear up malfunction in cold weather On jacks in a heated hanger it worked perfectly My local dealer s prognosis was 600 in a new gear motor and transmission Before taking the 600 route jacked up the plane outside for a gear cycle on a sub zero We solved our 600 problem with fifteen cents worth of electrician s tape Cold weather stiffened the brake hose on the left main As the whee
107. ice manual gear extensions to your heart s content reconnect your gear transmission even do a 1000 hour inspection under the watchful eye of a supervising IA of course If you really want to know your airplane up close and personal a set of jacks can help A WEAK LINK Glen Plymate ICS 02658 With a 1000 hour gear check done on my 1959 PA 24 only a year ago thought this year s annual inspection would be a snap Everything went well The engine and airframe were all o k and it was time for the gear check The plane was on jacks for the IA to have a look So into the cockpit went Master on and up went the gear with the IA under the plane watching how everything worked Then he asked for gear down Then up Then down and said there was something unusual he wanted me to see With the gear half down got under the nose so he could show me He pointed to the clevis at the end of the left drag link on the nose gear and showed how it would move if pressure was put on the nose wheel He wanted me to see what he had observed with the gear in motion so we traded places him in the cockpit and me under the plane Sure enough as the gear retracted there was movement on the end of the drag link as the gear neared the up position and stopped could actually see a slight movement in the clevis We discovered the drag link clevis had no torque It was loose in spite of being held in place by an updated reinforcement bracket that
108. ilure One item you could do to help all of us in this gear situation is Get together with your technical reps and print up 1 A detailed gear inspection sheet A detailed gear setting up procedure for an A C on jacks to insure any mechanic can do it without ending up with the gear trying to overreact in flight Make these papers available to the membership by mail at the cost of your creating and mailing them The manual Piper apparently doesn t do the job OBSERVATIONS The condition you describe has not been a problem with these aircraft The bulkhead cracking could be attributable to several things One is a possible gear up landing sometime in the past when the weight of the aircraft was put on the gear with the gear part way up The push retraction cables are very strong and have been known under such conditions to badly damage the area you speak of with no damage to the cables Another possibility is if the attachment to the bulkhead was loose for a long period each time the gear went up or down it would work on this area Another thing we have found is that if the gear is improperly rigged and allowed to go too far in either direction this can result in high stress on all parts A circuit breaker popping indicates a malfunction of some nature and should be determined at once The extra nose gear spring if properly installed has a negligible effect on a properly rigged Comanche ICS TIPS Chapter 7 Landing Gea
109. in and this time took apart the worm and nut end of the unit We put a micrometer on the balls which are the recirculating type much the same as in a car and truck manual steering box We found many of the balls were no longer round and that they were jamming against each other just when the power was needed the most in such a way that they were providing back pressure adding sufficiently to the load factor and naturally pop went the fuse again This time the fix was concluded AD 7 13 21 PREVENT GEAR COLLAPSE acquired a PA24 260 in February 1976 We have been Comanche flyers for about eleven years and are acutely aware of its gear folding reputation In 1972 we got a neat suggestion from another old Comanche flyer who passed on his standard habit pattern intended to thwart a gear fold His habit was to put his right hand on the gear lever and do two things while it moved upward 1 Actively help it get up into position this unloads the gear motor somewhat and reduces the operating current making less likely a circuit breaker trip out Feeling with the hand the slight clunk through the linkage system as it locks into place 2 We adopted his habit and use it routinely and we also add out loud right after the clunk that we see a green gear light When the gear AD appeared our first reaction went like this Why did it take so long It was several months before our annual came around and we would have to do ours We w
110. in there Bob had it up on jacks immediately diagnosed the problem repaired the transmission on the landing gear mechanism and had us back in the air and on our way home in a matter of hours The gear has operated flawlessly since then The lesson to be learned is that if you are having gear problems either take the airplane to Newton KS or have your fixed base operator remove the gear actuating mechanism ship it UPS to Bob Weber who will repair it the same day he receives it and send it back where it can be reinstalled and you will have no further gear problem Overhauling the transmission and the other aspects of the landing gear require special tools special parts special skills and special knowledge with respect to the problem and apparently very few people have these on hand AD 77 13 21 PREVENT GEAR COLLAPSE Landing Gear Like most of us went through the time consuming and expensive AD 77 13 21 complete rebuild of the system for all practical purposes One of the annoyances was after waiting for new bushing type bearings and paying airplane prices for them found most of them to be Sintered Iron type vs Oil Life bronze or brass Angry went through my local bearings house to 3 bearing mfg s looking for why All three said Cost Of course subject to FAA rules have to live with the sintered iron rather than put in better bronze or Oil Life etc ICS TIPS Chapter 7 Landing Gear and Brakes Page 42 of 103
111. ing got harder my eyes were bulging further and suddenly parts of the mechanism seemed to self destruct and the gear went down and locked This is page 2C 10 in the PA30 Service Manual ICS TIPS Chapter 7 Landing Gear and Brakes Page 28 of 103 PUSH PULL CABLE RIGHT GEAR PUSH PULL CABLE LEFT GEAR CASTLE NUT CASTLE nUT CABLE AOO RIGHT GEAR FUSELAGE CABLE ROO LEFT GEAR ROD CNO noo cno LEFT TORQUE ARM RIGHT GEAR RIGHT TORQUE ARM LEFT GEAR PUSH PULL ROO NOSE GEAR TRANSMISSION MOUNTING PIN THAU BOLT TORQUE ARMS TRANSMISSION SCREW TRANSMISSION SCREW NUT MOLL PIN STOP MOD ENO CONNECTING PIN RELEASE LEVCA RELEASE TUOC TORQUE TUBE EXTENSION CVER EMERGENCY TRANSMISSION ACTRACT SPRING Pa 30 SERIAL MOS 30 2 TO 30 92 TYPICAL SAFETY WIRE INSTALLATION INCLUSIVE TRANSMISSION RETRACT SPRING SKETCH A Pa 30 SERIAL MOS 30 93 AMD UP BRAKE ASSEMBLY MOTOR SUPPORT ROO 43 24665 360 TRANSMISSION TRANSMISSION LUG TRANSMISSION MOUNTING BRACKET TRANSMISSION MOTOR LATENSION SOCKET R GHT URTEMSION SOCKET LEFT MAIN SPAR RIGHT PUSH PULL CABLE PIGHT GEAR CASTLE NUT WASHER rr SKETCH 8 10 875 7 3 s n SEIS ARATE SED EE a SE gt My clever use of this strategy had sheared two pivot clevis pins in the release lever torn off the brake assembly and jammed the jammed actuator on through its jammed position and let the ICS TIPS Chapter 7 Landing Gear and
112. ing holds the whole mess up so it won t jam as mine did This retract spring is held on the unmoving end by a cotter pin through the floorboard of the plane near the lower left corner of the opening Piper noted on the drawing that the cotter pin should be adjusted as to allow the end of the retracting spring to be suspended 62 from the top of the floor board guess they meant for this to be interpreted to be 620 thousands of an inch with no plus or minus tolerance or that it simply was not critical since such close calibration of a cotter pin could be somewhat demanding for us ordinary people On my airplane the cotter pin had been pulled through the floorboard and had more than one inch below the floor This slack allowed the end of the retracting spring to unhook and fall off For lack of support of this spring the release lever jammed under the torque tube All of us have gone through the expensive gear bulletins and there is no doubt in my mind that all of the adjustments outlined in the manual are important know of no item covered by the gear bulletin or by adjustments close to right that will stop the emergency gear extension system from working The small spring and the 35 cotter pin will The point have been struggling to make is that in ten minutes of our time a visual inspection can be made of the adjustments described in Figure 7 14 and we can check the security of the cotter pin spring hanger and retracting spring intend to at reg
113. ing out and the collar was slipped over the jack The legs were fastened to the collar the collar was secured with a 3 8 bolt and all nuts were tightened For the next step the plywood base was placed on a level surface The jack was then tapped into position making sure it was plumb vertically The base was then held in place by a frame of wood around the bottom of the jack using pieces of door trim 1 5 8 wide glued and nailed into position See told you was using my carpentry skills Now for the finishing touches gave the base a coat of paint and screwed a pair of tension clips broom holders to each base for storing the jack handle The black glossy base is a nice contrast with the red jacks and silvery colored braces The jacks have proven invaluable and they work as well for a twin Comanche as they do for a single Maintenance which requires having my airplane s wheels off the ground can now be done anytime want Okay non do it yourselfers can join in again here ICS TIPS Chapter 7 Landing Gear and Brakes Page 87 of 103 If the challenge of building your own jacks doesn t turn you on at least the idea of owning your own should The advantages are inestimable Prices are reasonable too While you d spend only about 100 to build your own you can purchase a pair ready made for just a little over 300 with shipping If you are a determined do it yourself J C Whitney lists long stroke ram jacks in its catalog Stock N
114. is true that an alternating current induction motor on a shunt wound DC motor delivering a constant torque load near its rated speed will slow down and draw more current if the applied voltage is reduced a healthy DC series motor will not behave that way If one lowers the voltage on a series motor carrying a constant torque load i e lifting the landing gear the motor will slow down but require the same current If one leaves the voltage constant but increases the load torque req d four fold the current will double and the speed will drop by more than half suggest it would be prudent to check further 1 Be sure the mechanism is not binding up for some reason near the end of the retraction cycle Old dried out grease can cause this 2 Make sure the motor shaft is not bent or that one of the motor armature winding leads has not come unsoldered when it connects to the commutator A tight position bent shaft or a weak spot in the armature due to a loose lead will cause the motor to slow down or nearly stall in one position as the load increases near the end of the retraction cycle If the motor slows down enough the current will rise and the breaker may trip on or just after the weak spot The same excess current will flow with a better higher voltage battery but it may not flow long enough to trip the breaker A loose solder connection on the armature will cause evidence of arcing between that bar and the next Or you ca
115. ismantled One more thing want to add spoke with fellow Flyer John Willis one day about my problem He admitted he also had the same problem in his Comanche 59 model The fix to his problem was to spray contact cleaner in the wire wound rheostat ED The wire wound rheostat does not affect dimming of the gear lights The 10 ohm resistor on the switch does ICS TIPS Chapter 7 Landing Gear and Brakes Page 10 of 103 One other item has been added to our plane relating to the gear problem For 9 plus tax a bubble mirror was bought and attached to a homemade bracket placed in front of the left wing tip Now we are able to look at the mirror and visually verify Gear Down Works best in the daylight though SLOW GEAR OPERATIONS Q My Comanche gear works when it feels like it After sitting on the ground for over 24 hours the gear will not immediately cycle after takeoff but instead requires 30 seconds to several minutes before starting to cycle There are no blown fuses have had the gear almost completely rebuilt to meet specs in the service bulletin and keep the aircraft on progressive maintenance When the gear does cycle it does so freely and swiftly A Take a careful look at the nose and gear limit switches in that order They can get contaminated with dirt and oil The only way to check them is to replace them one at a time starting with the nose gear Another possible problem is sticking brushes in the landing gear mot
116. itted If Green Light Not On The first probable instinct is to recycle the gear This works most of the time but if a blockage exists a full recycle to the UP position could make matters worse We therefore propose cycling the position switch OFF and then DOWN as a quick fix If this doesn t work then perhaps we should spend 5 minutes or so to save 12 000 Maurice believes steps 2 and 3 are most important We must stop think and locate the problem Use a sharp eye in looking for broken components All components motor drive shaft should have normal alignment A mismatched stripe indicates a broken component but an unfastened nose gear pushrod may result in matched stripes A broken rod end should be easy to see but torque arms are fastened together on both ends and will attempt to move together even if broken If the motor drive shaft is stalled less than 1 2 travel it may be very difficult to see the nose pushrod connection Inspect carefully and thoroughly ICS TIPS Chapter 7 Landing Gear and Brakes Page 95 of 103 If we have an unsecured or jammed transmission we have lost our electrical extension capability and step 4 directs us to proceed directly to manual extension Any possible blockage to the manual gear train should be cleared lift jackscrew out of the way if necessary If components are broken then we are not going to get that gear down by any means and step S directs us to proceed to the partial gear or gear up landin
117. kes Page 91 of 103 Singles The book tells us to adjust the up limit switch until there is a 1 8 inch deflection or less with a 40 pound weight hanging from the Zen oleo where it meets the fork This is for the mains For the nose gear a 3 8 deflection and use a 40 pound weight as specified per the Service Manual This can be found in the Service Manual section 6 42 For the doors Hang a 3 pound weight from the inside edge centered forward and aft no more than 1 8 deflection This is also found in the Service Manual section 6 43 Twins For reasons not known the Twin Service Manual makes no mention of the 40 pound weight requirement It says only the main gear should be pulled snugly against the rubber block located in the wheel well and the nose gear should retract far enough Service Manual section 7 48 For the door Hang a 9 pound weight from the inside edge centered forward and aft no more than 1 8 inch deflection Service Manual section 7 30 Now that we got the gear up like it is suppose to be let s put it down in a manner in which it will stay down and locked For the single See Service Manual section 6 35 Installation of Gear Push Pull Controls items a and b and Service Manual section 6 36 Adjustments paying particular attention to NOTE when adjusting the complete landing gear system follow the adjusting procedures in sequence as outlined in paragraphs 6 37 through 6 42 Always jack the aircraft befo
118. l and polish the struts Making one loop around the strut and then pulling on both ends with a back and forth motion will polish the struts quite effectively Do this after cleaning with gas and before spraying with Teflon or silicon BUNGEE CORD TOOL Here is an inexpensive and easy to make bungee cord installation tool All you need is an 11 piece of 1 2 thin wall conduit a 13 piece of 1 2 threaded rod 2 nuts and 1 washer First make a 1 4 deep cut in the end of the threaded rod Use two hacksaw blades in the saw This makes the cut wider and facilitates spreading apart Then spread the rod apart to form a V as per drawing Tighten the nut and washer against the base of the V The washer prevents the bungee roller from slipping off the side of the tool The next step is to make two cuts in the end of the 1 2 conduit to form a 1 4 X 1 4 tab on each side Bend the tabs out at right angles to the conduit The tabs serve the same purpose as the washer on the threaded rod Make two more cuts on the conduit to form a V as per drawing Your bungee cord tool is now complete Wasn t that easy Now to put your new tool to use Remove the bungee cord inspection plate and wheel well liners Jack up the airplane and retract the gear part way to relieve some tension on the old bungee You should leave enough room so you can get your head up into the wheel well area Needed for installation Insert the tool between the bungee with the conduit towar
119. l retracted the hose would not flex enough and protruded between the wheel door and the wheel door stop thus keeping the wheel assembly from completing its cycle enough to activate the limit switch which turns on the wheel up light and shuts off power to the gear motor A small amount of tape properly placed keeps the hose from sliding too far through the retaining eye thus solving the problem SINGLE FORK MODIFICATION Modifications are generally for the purpose of improving appearance improving performance or meeting safety requirements In the case of changing the main gear on older Comanches of a single fork you accomplish the first two changes surprisingly easily What is involved 1 A direct exchange of fork assembly 20709 00 for the appropriate right and left landing gear strut assemblies Both are illustrated on page 198 of the 1966 issue of the Piper Comanche Parts Manual Essentially it is an exchange of the fork type used on the 260 and 400 The exchange was involved with was made during the winter so we put the housing assembly on the stove to expand it and we put the strut assembly in the snow to contract it The two parts went together and have stayed so without any problem ever since 2 the next step is to move the brake housing from the outside to the inside As recall this was rather easy and only involved some spacers and perhaps a change in the length of the ICS TIPS Chapter 7 Landing Gear and Brakes Page 6 o
120. lapse after manual extension In the summer of 1974 my ex partner was flying to Florida from Lancaster CA in our 1959 PA24 250 After takeoff from Lancaster the gear up limit switch came loose causing the gear motor to burn out defective breaker in the up position Upon arriving at his first fuel stop Winslow AZ he discovered the faulty motor He had to use the back up or manual extension After cycling the gear several times by hand and receiving a green each time he proceeded to land As he touched down he hit a dip in the runway and the gear collapsed Later that summer called the controlling GADO office in Phoenix to find the results of their investigation and they indicated that they have had five or six other accidents of this type They said that when using the manual extension the only locking device utilized is the gear linkage coming over center When using the gear motor the worm drive will prevent the gear collapsing even if the gear linkage comes back over center don t know what the service letter entails as far as parts and labor but until comply with it am going to put a big foot against the manual extension lever pushing it forward anytime use the gear back up system HAND BRAKE SUPPORT BRACKET have a question for the owners of 1960 and older Comanches When was the last time you or your mechanics looked at your hand brake support bracket would guess most of you would say Never looked a
121. ld be bent Short cuts are only good if they are carefully evaluated for the possibility of damaging something would not risk that short cut ED We agree with the last paragraph completely GEAR DOOR CONNECTING ROD Two items to check with your mechanic and in your post repair inspection are the landing gear door connecting rod if it has been disconnected It is possible to reassemble the door with the spacing backward This will shorten travel on retraction jamming the gear before it is fully retracted and it will bend the rod A paint shop did this to me The gear will come back down and lock okay but you will need a new arm and the circuit breaker will pop when the gear can t fully retract So it is recommended to look at the rod bolt and make a sketch before disconnecting so that it goes back together the same way GEAR UPPER DRAG LINK BOLT We have another item which you or your mechanic will need to check We have found the bolt item 7 installed the opposite way to that shown in the drawing This will permit the end of the bolt to dig into the spar web as the gear goes up and down It can destroy the spar This bolt must be installed as shown in the drawing i e head forward nut aft ICS TIPS Chapter 7 Landing Gear and Brakes Page 50 of 103 CRACKED SIDE BRACE STUD Some recent calls from alert mechanics working on members Comanches has brought to my attention that another look is needed with regard to the stud main gea
122. ll pin at each end of the subject rod assembly to supplement the weld 14 Service Letter 596A dated September 5 1975 addresses the need to install a new Nose Gear Aligner Guide Bracket Assembly and new High Strength attachment bolts 15 Service Letter 650 dated September 27 1973 addresses Inspection of Landing Gear Retraction Transmission Assemblies to ascertain that the sleeve is properly staked to the transmission body 16 Service Letter 782B contains eight pages on Inspection of the Landing Gear Manual Extension System This SL is the basis of the 1 000 hour gear inspection AD For most Comanches the FAA has issued a total of six AD s addressing some gear problem They are 59 06 05 on nose gear bungee 63 27 03 on landing gear circuit 64 22 03 on gear safety switch 65 25 03 on nose gear drag clevis 77 13 21 on preventing gear collapse 95 20 07 on Landing gear side brace stud and 97 01 01 that supersedes 95 20 07 A Service Letter or Bulletin preceded most of these All of these Service Letters and Bulletins and others as well address some aspect of our landing gear operating system Complying with each of these can be expected to reduce the incidence of gear problems This will reduce our injuries to our persons our aircraft and our pocket books Where do you as a pilot learn about these issues If you subscribe to the AdLog System of Aircraft Maintenance records you receive all of the AD s issued for your aircraft and receive
123. llow the rudder peddle push rods through the fire wall to their connecting point on the what s it that makes the nose gear move to the right and left you ll find a kind of half closed funnel shaped Y shaped track in which a roller is supposed to be guided when the gear comes up As the nose gear retracts the roller is forced down to the bottom of the Y If the rudder pressure is being held to the right or left usually right to counteract P factor then the aligner forces the nose gear to retract straight into the wheel well Okay so now you ve found the elusive aligner Why should it be checked and how does one go about checking same The following sad story will answer the first question Once there was a Comanche pilot who had an unfortunate mishap and damaged his Comanche s nose gear The Comanche was repaired but the alignment of the aligner was not aligned correctly so that the aligner aligned but not very well The Comanche was sold to a good but unsuspecting pilot who flew his cherished bird for many happy hours However one fine crosswindy day our unsuspecting pilot took off with lots of rudder action and placed the gear switch in the up position Up came the gear to the halfway point and pop went the gear motor circuit breaker By n by our good but unsuspecting pilot reset the breaker and placed the gear switch in the down position but again the breaker popped So here was our pilot with his gear stuck up Now what would you
124. lly this tweaks and bends the old wiring harness until wires break saw Matt Kurke s ad in the FLYER for his wiring harness and decided to install it Matt said he can do a PA30 installation in four hours well took me more than four hours however the result is outstanding ICS TIPS Chapter 7 Landing Gear and Brakes Page 89 of 103 recommend this wiring system of Matt Kurke to every Comanche owner His system comes with more flexible wiring which is protected by a sleeve The entire system comes in a box with screws tie tapes switch covers to replace the old fabric ones on the switches which have eroded away on all Comanches by now and the harnesses themselves are bundled and identified with original Piper codes connectors installed and totally ready for installation His system contains all the parts you ll need plus an outstanding wiring and installation book which is invaluable when you are dealing with old wiring like was on this installation Matt s system is not inexpensive but when look at the system and the time it would have taken me to have figured it out coded wire crimped and installed connectors my cost would have been through the roof making Matt Kurke s system a good buy In fact it is a WIRING SYSTEM not a bunch of wires and should be looked at that way Matt s system should be installed on EVERY Comanche since the difference is enormous in safety and serviceability give this wiring system an un
125. mply designed system compared to other airplanes Furthermore my gear doesn t clunk hasn t clunked in the past and clunking would not be acceptable as normal to me My pilot friends have frequently remarked about the gear s smoothness and lack of clunking or banging would not recommend adjusting limit switches unless the designed mechanical throw of all gear legs is checked first Otherwise you may be adjusting switches to encourage their operation when gear legs or leg are not in the correct position Using manual assistance on the gear handle is accurately described in the article as a habit pattern think this is adopting a symptom that should be telling the owner there s something wrong As a veteran airline pilot friend of mine likes to say referring to pilot habits if you do something wrong enough and long enough you get good at it It is amazing to me on occasions of fly ins luncheons etc to learn how many owners accept symptoms of problems as normal and how they learn to reset popped circuit breakers almost as part of their pre landing check list etc instead of going to the root of a problem One owner told me he always got a couple cups of gas expelled out of the bottom cowling on engine shutdown and was told it was normal had had much less of this and discovered a defective diaphragm in the injector servo which was an acute fire hazard JAMMED GEAR EXTENSION suggest that all Comanche owners imme
126. must be out of adjustment or faulty Gear extension was normal and upon returning to our hangar we placed the aircraft on jacks While observing the transmission assembly with the gear in transit noticed a distinct wobble of the coupling as it turned When the up limit switch cut off power to the motor the motor brake could not function properly because of the wobbly coupling knew had found the problem Upon removing the coupling from the motor transmission assembly found that the openings which accommodate the slotted motor shaft on one side and the slotted input shaft of the transmission on the other were elongated as can be seen on the photograph After installation of a new coupling the motor brake functioned perfectly and during subsequent flights gear operation was back to normal While on the subject of the coupling remember a maintenance seminar given by Bob Weber of WEBCO during the Louisville convention Bob suggested that the gear could be extended without benefit of electrical power and without disconnecting the transmission by placing a finger on the aft facing part of the coupling and turning it using upward strokes have tried it on jacks and it worked but took a long time It could not be done if the motor had seized In the air it would be hard to do Especially the last part when the nose wheel has to move forward against the slipstream Also the motor brake would have to be disabled think it would be easi
127. n filed along with a recommendation that the comments appear in Airworthiness Alerts for lA s Again these damaged and severely worn components only reinforce my ongoing argument that aircraft owners should demand and pay for quality maintenance to meet factory service manual criteria GEAR BUNGEE ARMS Due to the number of cracked and broken gear arms we have found while working on Comanches thought it should be brought to the attention of the members The picture shows one arm that has one side broken off the other was cracked and would have broken soon The arm cracks or breaks and gets so loose that the bungee instead of ICS TIPS Chapter 7 Landing Gear and Brakes Page 32 of 103 holding down will actually hold it up and keep the arm from going past center and locking the gear down Arrow points to missing piece Pictured is the main landing gear showing arm see arrows and its position in the gear A good way to check to see if there is a problem crack grab the arm where the bungee attaches and firmly try to move it If there is any movement it probably is cracked The part of the arm that cracks is inside the main gear trunion housing and it the arm will have to be removed to check The one bolt on the end of the arm is what holds it in place If you take the arm out be sure to put the spacer washer back on the arm The inside spacer could fall out so be sure you put it back on We are keeping some of t
128. n hear it with a head set connected across the brushes ICS TIPS Chapter 7 Landing Gear and Brakes Page 24 of 103 A battery which will crank the engine a bout 2 hp should operate the landing gear motor less than 1 2 hp with the charging system helping unless the gear motor is drawing more than normal Current GEAR MAINTENANCE On the gear lube There are 2 small grease fittings at the top end bell fitting on the actuating arm at the top of the strut They are almost impossible to get on with a grease gun short of disconnecting the arm to swing it down Check yours after each annual for signs of being greased That is a big important ball joint ED These are best reached with airplane on jacks and gear at 45 degrees GEAR TRANSMISSION The landing gear has been a problem and from all have read in the Flyers a lot of tribesmen have had problems But have not read of anyone who has taken the gear box apart that the motor is connected too Inside this gear box casting is a ridge that is supposed to hold the bearing in place that is pressed onto the end of the jackscrew have two castings one the ridge is broken off and the other is broken to the point of coming off Have you heard of this problem The only cure is to replace the whole thing Part 25720 00 which is far too expensive ED The gear box is rebuildable We suggest you check with your mechanic to see if he can rebuild it Webco Aircraft ICS 4012 Newton KS a
129. n inene s rE annua EEEE e AE pae Eran IN er e au atncenantnierns 56 NOSE WHEEL BRARE Sua adios 57 RUDDER ALIGNMENT 0 dai cus aara aa a anaa A A a mints sidetnventintseanscntenetouncdch nettena 57 BRAKES 180 2D ova 59 BUNGEE ARM CRACKS vent ho bd aiieieo eyiyi aia dedita 60 PROBLEMS WITH SEA Ristorante AAA Aaa 61 FAILED NOSE GEAR PUSH PULL ROD ASSEMBLY ocnncccccccncccncncnononnnononanonononnnnancnnnnnn nos 62 BUNGEE TOOL uta iaa dora aca RAE iii 63 EMERGENCY GEAR RELEASE ARM PROBLEMS cocccccccccccononnccnnnnnnnnncnnnnnnnccnnnnnonononanoncnnnnnnnns 64 UNDER CARRIAGE PROBLEMS WITH PA Dindir 67 PROPER DOCUMENTATION OF LANDING GEAR AD 77713721 eiee 67 EMERGENCY GEAR EXTENSION curras 68 NOSE GEAR DOWN LOCK SPRIN Gianna atea 69 GEAR SEU DS EE E EE ATE E ETT AT ATT 70 MORE ON THE LANDING GEAR SIDE BRACE STUD oooccccccccccnnncnonancncnonanannncnananannnranann nono 71 GEAR WARNIN O Gis iia ar 72 ELIMINATING THE POPPING OF THE GEAR MOTOR CIRCUIT BREAKER 72 FROM THE TOOL BOX OF MAURICE TAYLOR oooococcccconncccnanancnnninannnononancnn cnn nannn nn conan nnnnncnnns 72 NOTES ON THE LANDING GEAR seins ia 73 THE COMANCHE LANDING GEAR wits icdvncctcsscces satasosgeksncennestesnetewntannnicassidosdestanaresdieatamnecte simmons 74 FAA GIVES GOOD ADVICE usara 76 THE 1000 HOUR INSPEC PION sitiar A a AA 78 MIRROR MIRROR ON THE WALL WHO HAS THE FAIREST GEAR OF ALL ee 80 LANDING GEAR EMERGENCY siiciissecxaicavaditine ca sehpenaiicenuetaa
130. ne of the gears The Letter contains an attachment with a seven page Inspection and Rigging Instructions for the PA 24 Landing Gear System A two page trouble shooting guide is included 6 Service Letter 356 dated March 31 1961 addresses the problem of 25 amp circuit Breakers popping in the landing gear circuit and recommends the installation of a 30 amp circuit Breaker 7 Service Letter 365 dated January 3 1962 addresses the need for a special lubricated bolt for the Nose Gear Drag Link ICS TIPS Chapter 7 Landing Gear and Brakes Page 81 of 103 8 Service Letter 366 dated January 3 1962 addresses the replacement of the Nose Gear 8 Clevis with a new high strength fitting 9 Service Letter 379 dated August 10 1962 addresses the problem of wires in the landing gear switch harness becoming broken at the switch A kit F754 475 is offered as a solution 10 Service Letter 380 dated August 8 1962 addresses a problem with Main Landing Gear Door Hinges and Nose Gear Door Hinge Bushings 11 Service Letter 445 dated April 21 1965 addresses the installation of a Nose Gear Drag Link Reinforcement Bracket 12 Service Letter 447 dated March 26 1965 addresses the necessity that the Landing Gear Transmission Retract Spring be inspected and if missing or not functioning properly be replaced 13 Service Letter 546A dated March 10 1970 addresses the need to reinforce the Nose Gear Push Pull Rod Assembly by installing a ro
131. ng ammeter or precisely timed b recording the voltage 2 Total side shake on each main gear ED For those of you who follow these excellent checks be sure that you also monitor voltages when checking current drain multiplying the average voltage by average current drain in amps will give you the average power in watts required to raise the gear If the power required to raise the gear after servicing is lower then you have improved things If the power required to raise the gear is higher it s back to the boards GEAR WARNING HORN ADJUSTMENT In the October Flyer a member asked for advice on intermittent operation of the gear warning horn Yes it can be corrected Disconnect the two wires at the horn and remove the horn from its bracket Once outside and exposed connect it to the aircraft battery or other 12 volt DC source for testing using one of the two test leads as a switch by touching the horn wire Use a good light so you can see well and you ll soon discover how the horn works and how to adjust it It works similar to a relay or solenoid except its contacts are in series with the coil itself When power is first applied via the throttle and landing gear switches the armature pulls in breaking the connection to the coil that exists through its own contacts Then upon returning to its original state the contacts are again made and the cycle repeats itself It thus vibrates on and off A diaphragm is physically connected
132. ng out together We applied mild heat from an electric heat gun to the bearing support which seemed to help Of course DON T use a torch ICS TIPS Chapter 7 Landing Gear and Brakes Page 49 of 103 The bungee arm was indeed bent right at the area of the shims It didn t bind in the bearing or in the landing gear housing but it had to be cut in two to remove it from the bearing The service manual mentions Kit 761 082 for adding a second nose gear down lock spring My Comanche now has this improvement as well The manual also recommends that the assist spring 83302 40 be replaced any time the bungee cords are replaced suspect this doesn t mean every three years since think the original intent was that bungee cords would go a longer time replaced my springs because they looked 30 years old The pivoting attachment points for the assist spring needed a bit of cleaning and lube to correctly pivot again as well All of this work has resulted in very smooth gear operation as well as a marked increase in safety One more comment on bungee arms saw a letter in the Flyer recommending using a large adjustable wrench to install the bungee by turning the arm with the wrench would heartily NOT recommend this practice after examining the bungee arm The tapered nature of what you are grabbing with the wrench as well as the close proximity of welds looks to me like trouble The weld could be cracked and or the part of the arm being grabbed cou
133. nition OFF If Nose Gear Not Down 1 Accomplish Item 1 under Gear up Landing except omit zero flap landing 2 Extend main gears electrically to full travel on gear stripes if possible If manual extension previously conducted or necessary and safety lock not installed plan to hold extension handle firmly forward with foot on rollout Have tower inspect gears to confirm positions Just before flare Fuel selector amp Master Switch OFF At touchdown Ignition OFF Hold nose off as long as possible DARA If One Main Gear Not Down 1 Accomplish Item 1 under Gear up Landing 2 Plan landing off centerline of concrete runway with extended gear near edge of runway 3 Extend functional gears electrically to full travel on gear stripes if possible if manual extension previously conducted or necessary and safety lock not installed plan to hold extension handle firmly forward with foot during roll out Have tower inspect gears to confirm positions Just before flare Fuel selector amp Master Switch OFF At touchdown Ignition OFF Use full aileron to hold wing up as long as possible Use maximum rudder amp brake to hold aircraft on runway Have passengers exit aircraft as rapidly as possible after landing ADOS ABNORMAL GEAR OPERATION The following is an explanation of the abnormal gear operation checklist Understanding is preferable to blind compliance Explanation on some obvious items has been om
134. noting that the hydraulic line connects to the middle of the brake assembly as opposed to the newer style brake assembly which has the hydraulic line attaching at the top of the assembly It is interesting to note that the Cleveland Prod Directory lists the old style as P N 30 12 At any rate in working on the older model brakes have noticed some points that owners should be aware of that are not mentioned in the Piper Service Manual personally consider the older style brake to be a better brake than the newer styles if certain procedures are followed There seems to be some confusion concerning the adjustment feature of these brake assemblies First of all pads can be changed without removing the assembly from the aircraft I personally remove each brake assembly completely Service Manual page 1 K12 Fig 6 28 is reproduced here for your convenience When removing the pressure plate which has the pads attached to it with six rivets you will have to remove a nut amp washer and a spring amp sleeve in order for it to come free After these are all removed what is left is the brake cylinder with three movable parts in it still The two 2 pistons should be pressed back into their holes at this time They should move easily with just thumb pressure If not there is something wrong and further disassembly is required The third movable part is of prime importance It is called the retract cylinder It is basically a steel bushing which is
135. nting your chariot will take a little extra effort especially if your own legs are not long ICS TIPS Chapter 7 Landing Gear and Brakes Page 8 of 103 ED Strut extension on all Comanches should be as Directed in the Comanche Service Manuals GEAR CIRCUIT BREAKER When first brought it home took my wife and kids around the pattern and had my first and only emergency The gear wouldn t come down After trying everything lowered the gear by hand and landed safely subsequently discovered two things One past annuals had not properly serviced the emergency gear and as a result it took a considerable amount of effort to get the emergency gear handle loose to lower the gear Have you tried lowering the gear by hand with your plane on jacks Also discovered the gear didn t come down because the breaker had popped when tried to lower it at 150 mph thought the breaker was in because didn t push the side panel in far enough to feel the right breaker Anyway I m glad it happened when and where it did because we solved the problem while had another good pilot on board GEAR FAILURE GEAR COLLAPSE had trouble with the amber gear light on my PA24 250 blinking off and on The circuit breaker would also pop By lubricating the pull rods in the wheel well more frequently than recommended my problem seems to have been solved and saved costly repairs would like to comment on the service letter pertaining to gear system col
136. o O7ND1507W for 39 99 Capacity is 3 tons range is 24 9 to 44 6 the same specifications as the ready made jacks described below Air Sea Inc Auburn WA 1 888 939 7340 or 253 939 7340 offers a 3 legged jack with a steel angle base for 149 00 each plus shipping The Jack House Inc North Little Rock AR 501 835 6033 offers a 4 legged jack with a steel channel base for 154 00 each plus shipping The brace legs are round similar to my homebuilt jacks For stability it s your choice but lean toward having four legs Okay you ve decided having your own jacks is right for you but wait that s not all You ll need a tail anchor too For me put an anchor in the hangar floor with a 3 8 eyebolt and have a chain for hooking to the tail skid If a permanent anchor is not feasible a portable one could be used Others have said it requires about 200 Ibs to hold the tail of a PA 24 down I d prefer a safety margin of at least 50 and would use more like 300 pounds Two cubic feet of concrete in a roll around box or barrel should be enough That d be five 60 Ib bags of sack mix concrete with an eyebolt anchored in the center I m sure there s other ingenious ways you can think of to secure the tail too Hey it s an opportunity to be creative With your own jacks either homemade or store bought you can participate in as much landing gear maintenance as you want change tires lube bearings replace bungees adjust gear doors pract
137. oblem at all getting the gear down Remember in this case you will not have a gear warning horn or green light The flight instructor will have shown you where the emergency handle should be when the gear is down not only on models with the gear handle above the floor boards but also for the ones that are below the floor boards NOSE GEAR DOWN LOCK SPRING Maurice Taylor had a most interesting call from Wayne Damico ICS 12986 He just recently bought a 180 Comanche After looking it over he discovered that something about the nose gear didn t look right to him The two springs on the nose gear weren t parallel to each other My understanding is that a short time before he got the aircraft the 1 000 hour gear inspection Piper S B 782B had been C W The AP IA had basically completely disassembled the gear and in putting it back together had installed the nose gear drag link cross brace backwards Also the lugs that attach to it were on upside down This action will make the springs intended to hold the gear over center in the down position do just the opposite unlatch or pull the gear over center in the up position Keep in mind that these springs have no effect on the gear when it s operating normally they only come into play when the gear has been disconnected to use the emergency system For example a number of years ago a member had this same inspection done then flew the airplane a year or more Then on a trip to Mexico the gear didn
138. often neglected item the transmission Many people tell me they look after it by smearing some grease onto the transmission screw while in flight when it is exposed with the gear in the up position Lubrication of the screw is important too provided the old grease which most likely has collected dirt is ICS TIPS Chapter 7 Landing Gear and Brakes Page 36 of 103 first removed But to lubricate the input and driven gears inside the housing the unit has to be removed from the airframe and opened up See the accompanying notes which are in the PA 24 maintenance manual 3 Landing gear and flap transmissions and screws identify type of transmission installed Dukes has label on transmission housing Dura has part no 1010250 stamped on transmission housing Disassemble and clean When reassembling transmission fill Dukes transmission with Dukes no 4 lubricant Fill Dura transmission with MIL G 7118 or MIL G 23827 great No substitution is allowed in either transmission Apply a thin coat of MIL G 7118 or MIL G 23827 grease on actuator screws See note 7 7 Transmissions should be disassembled cleaned inspected and lubricated at each 500 hour interval or annually actuator screws should be lubricated at each 100 hour interval or annually The transmission cover 7 has to be removed to clean and refill the transmission housing After reinstalling the transmission make sure that the spring 14 or 15 is hooked up again ICS TIPS Chapt
139. oken and jammed There was little evidence that this transmission had been serviced in many years Webco repaired and returned the gearbox within five days My Comanche has over 1 100 hours on it since that incident with good maintenance and without another gear problem After sharing this experience with a couple of other Comanche pilots learned a really good way to get experience manually extending the gear During the annual inspection when my airplane is up on jacks and the A amp P is cycling the gear often take the opportunity to actually practice a manual extension There are some caveats on practicing this kind of extension that are covered in another article in this issue The important things to remember from this story are 1 Don t panic Treat any gear issue as a problem not an emergency 2 Fly the airplane first 3 Use whatever resources passengers approach local controller your A amp P etc are at your command 4 Follow the emergency extension checklist 5 After landing be extremely careful when taxiing And above all use common sense Use A Check List COMANCHE ACCIDENT INCIDENTS STATISTICS May 1 1987 to Dec 31 1999 Omri Talmon ICS 07949 Since May 1997 have followed on a constant basis the publications of the FAA s Office of Accident Investigation on the Web have through the same medium access to the aircraft registration database have collected all the US accident incident data related to the Comanc
140. operation and horn operation prior to landing but save the practice emergency extensions for the hanger while on jacks What a feeling of satisfaction it is to know that your gear is in virtually as new condition And it even looks nice Now as you and your mechanic return to the field and prepare for landing at the completion of the test flight please do me and yourself a big favor DON T FORGET TO PUT YOUR GEAR DOWN BEFORE LANDING MIRROR MIRROR ON THE WALL WHO HAS THE FAIREST GEAR OF ALL Bill Creech ICS 03423 Maurice Taylor has frequently stated that the Comanche gear is simple strong and dependable So how come we have gear up landings and gear failures The answer comes in two basic categories The first is pilot induced We simply forget and don t put the gear down and sometimes we don t do the right thing to get the gear down when there is a problem The second category is where the gear does not receive the necessary maintenance If the pilot has more training and better knowledge of the gear then both of these situations can be improved All of the articles in this special issue address some phase of the problem This article will address what the pilot needs to do to insure that the gear is properly maintained ICS TIPS Chapter 7 Landing Gear and Brakes Page 80 of 103 Do you have a responsibility for the gear maintenance The FAA considers the pilot responsible for having the maintenance done and for seeing that all
141. or On jacks or in flight tap it with a hammer to see it this will make the contact To determine if you are getting current to the motor wire a test light to the plus side of the gear switch in the up position and the other to ground An immediate current flow indicates a problem between the switch and the motor No current flow indicates that the problem is at the switch or outboard A sticky squat switch would prevent the gear up circuit from being active when the gear extends on take off After a few minutes of flight vibration could cause it to finally close and energize the up circuit SYNC THE GEAR Q What does the PIPER service manual mean when it says sync the gear Is it important A The Service manual does not detail the procedure required to make certain that a Comanche landing gear is properly synchronized As a result of complying with AD 77 21 13 we are receiving reports of gear problems which include collapsed gear Some have been determined to have been caused by the gear being improperly synchronized and tensioned We suggest especially if you have had the gear AD done that you have your shop verify that they performed the following check If they have not it should be done as soon as possible because the probability of popped circuit breakers and a gear collapse exists It is also possible that neither will occur at once thus giving the Comanche owner a false sense of security about the integrity of his gear 1
142. ot work at all or is so weak that you have to remove your headset to hear it It should be an ATTENTION GETTER The louder the better An inoperative horn should be a no fly item Unfortunately there is no safe way to check it during pre flight so always checked mine during descent to insure it was working ICS TIPS Chapter 7 Landing Gear and Brakes Page 75 of 103 In case you should have a total electrical failure thus the gear must be lowered by the emergency procedure and the horn and light warning systems will be inoperative the following should be considered Mark or paint a line or use tape to align the moving pails of the gear drive with the floor in the emergency gear well so that when seated in the pilots seat there is no parallax in viewing that the marks line up This will insure that the gear has gone through its complete cycle and that the gear is down Remember no one not tower personnel other pilots mirrors or anyone else can tell you that the gear is down They can say it looks down or that it is only partially down or it is still up but they can t tell you that it is down Don t get yourself into a dangerous situation by buzzing the tower formation flying with an unknown pilot or anything else to trying to determine if the gear is down You have all the necessary information in the airplane if you utilize it Situation You select Gear Down and it cycles and you feel the nose wheel steering engage but no Gea
143. placed with an entry reading Complied with AD 77 13 21 replaced bungee cords Replacing the bungee cords every three years is only one requirement of paragraph b and does nothing to comply with para a Note that para b also requires that the bungee cords be inspected for specific defects and para c requires that the bungee cords be inspected every year or 500 hours whichever occurs first That means that every year on your annual inspection the mechanic should have made a logbook entry like this inspected landing gear bungee cords per AD 77 13 21 para b or Replaced MLG bungee cords per AD 77 13 21 para b Check your logbook and see if your bungee cords were inspected last year and signed off per the AD requirement Your aircraft maintenance records should include a list of AD s plus information as to when it was last Complied with and when the next inspection is due This can be a list in the back of the logbook or on a separate sheet of paper AD s are either one time or recurring AD 77 13 21 is a recurring AD and your aircraft records must have an entry to indicate when para a is next due and a clear understanding as to when para b is next due both date and total hours Take a look at FAR 91 417 a 2 V and you will find that it is the owner or operators responsibility to maintain the maintenance records not your mechanic and to know the status of any Airworthiness directives continue to find aircraft at
144. port in 1981 six months after owning our plane The FAA called it a gear up pilot error but to the three pilots in the plane at the time it was a gear failure We had been having a problem with the gear light coming on after extension and lock After many retractions on jacks our maintenance man informed us it was a micro switch out of adjustment we had them all replaced That weekend we were shooting approaches and on the third one the gear failed After touchdown the left main retracted under stress a few seconds later the right main failed We were almost a complete stop before the nose failed and the gear horn came on The gear light was green when we shut down and left the plane We found the left gear extension retraction rod sheared off at the threads This rod extends and retracts the gear into the locks The locks bear the stress of landings not the extension retraction rods Our guess the previous owner made a hard landing causing the gear down and locked light to go out Apparently all their maintenance man found was a micro switch out of adjustment He readjusted the switch and that was the end of the problem for them anyway In reality the extension retraction rod became slightly bent and was pushing the gear to the lock on the left side and into the locks on the right main and the nose From that point on we were landing with all the pressure on the left rod As time went on the left side started to fail causing us to sta
145. press chuck Adjust the drill press spindle and table so that small end of tool can be milled to shape of roller Note This step is most important because this will prevent the roller from slipping off tool with bungee on it To make the 3 8 notches used a ratchet handle with sandpaper around it These are to help center the bungee Two of these are required on each end as shown on the drawing To use the tool mount the new bungee on the tool using a vise and a rod or screwdriver which will go through the hole in 18081 00 roller which you removed from the aircraft after removing the old bungee Be sure that the roller is properly seated on the tool The end of the tool is the exact shape of the roller so the roller won t slip off Place 20845 00 bracket and bolt on the roller these were also removed from the aircraft With the gear in a full up position fasten the bracket and roller with the shock ring and tool attached to the aircraft Then with the large end of the tool over the bushing on the bungee arm assembly have a helper lower the gear a small amount just enough to take the bungee off the tool Then remove the tool by pulling out the small end The idea and design for this tool was given to me at the 1978 annual meeting in Vero Beach by a member ICS TIPS Chapter 7 Landing Gear and Brakes Page 63 of 103 ROLLER 18081 00 As modified 3 8 Notches 2 each end PEETERS ENEE 19 3 8 EMERGENCY GEAR RELEASE ARM PROBL
146. r Down Light Some seconds or minutes later the light does come ON This usually indicates that the wires from the gear down switches to the gear down light are broken and need to be replaced Remember the Gear Down light does require all three down switches to be closed and that all relevant wiring is OK The Gear Warning Horn operates only off the nose gear Down switch Thus if you know your warning horn is working and you retard the throttle s if the horn does not sound the nose gear is down and since all three gear are mechanically tied together all three gears discussed should be down Always check the alignment marks discussed above to insure that the gear is in the down position This will give you the warm fuzzy feeling you need while you are trying to make the softest landing of your career Just to give you an idea of how dependable the Comanche gear system is in the 1000 hours in my 180 and 2000 hours in my Twin plus the hundreds of hours training in Comanches have yet to use the Emergency Gear Extension procedure except on jacks during an annual just knocked on my PC desk a few lines to insure that will always be able to make that statement Always remember the traffic pattern is not the place to solve a gear problem As soon as one is noted depart the pattern after informing the tower if appropriate Climb to a safe altitude away from traffic and then take your time to analyze and solve your problem Remember to
147. r and Brakes Page 13 of 103 Through a cooperative effort with ICS Piper has worked out changes to be published shortly concerning Comanche gear maintenance However a qualified mechanic familiar with the Comanche should have no problems in setting up the gear using the current Piper installations and manual Since Comanche gear has been a basically trouble free system most mechanics are not too conversant with it yet they will attempt to work on it often with dire results For instance it has been recently reported that the arms which attach the bungees to the gear were reversed on a Comanche Why they were removed is unknown since they have nothing to do with the gear AD Now instead of holding the gear over center and locked when extended they tried to hold the gear retracted Imagine this owner s surprise when he attempted to extend the gear after flying 1 000 miles from the shop which had just done his Annual GEAR OPERATIONS An article in the January 1979 Flyer pertaining to the Comanche gear prompts me to write giving my thoughts I m neither an engineer nor an A amp P mechanic but I ve owned flown and maintained my 1968 PA24 260 for almost 8 years and love the machine and its performance cannot accept the statement that anyone should be acutely aware of its gear folding reputation Because don t believe Comanches have an established reputation for gear folding at all Rather they have a comparatively trouble free and si
148. r and master switch off about flare point and ignition off on contact There is conflict in deciding which comes first We cut the fuel off early because the engine should run for over one minute at approach power on residual fuel and we can t see putting your head down after contact to feel for the selector who s keeping the airplane on the concrete The master switch is needed only for radio contact and you might wish to inform the tower that it will be off for landing If Nose Gear Not Down On the check list for nose gear not down we omitted reference to a zero flap landing because the aircraft should tip forward after touchdown without flap damage The remainder is obvious If One Main Gear Not Down Landing on the nose gear and one main gear is preferable to a full belly landing But we do think you should choose a concrete landing surface A wingtip digging into the turf may cause total loss of control Numerous military and airline aircraft have been landed on one main gear without leaving the runway This procedure involves landing off the centerline with the extended gear near the edge of the runway to provide more concrete in the direction of turning holding the wingtip off as long as possible and then using maximum brake and rudder as the wing contacts the runway Manhandle the aircraft if necessary If successful damage should be limited to wing tip and prop There is a strong feeling amongst our A amp P AS friends that landing to
149. r gear maintenance ICS TIPS Chapter 7 Landing Gear and Brakes Page 82 of 103 LANDING GEAR EMERGENCY Joe Shelton Let s start with a basic premise unless the airplane is low on fuel the weather is a major factor or there is some other mechanical problem a landing gear problem is NOT an emergency At least not immediately If the landing gear won t extend for whatever reason the most important thing is to know what you have to do and then do it A gentle reminder the first and most important thing to do is to fly the airplane It s Not An Emergency Let s look at an example of a gear emergency in a Comanche A number of years ago was returning to my home airport San Jose California in relatively new to me Comanche San Jose International Airport serves most of the major airlines and has mountain ranges parallel to the approach path on both the east and west sides The weather was a high thin overcast with about 15 miles visibility lt was very dark and there was no moon The time was approximately 12 30 AM As executed my pre landing check list selected Gear Down and the landing gear only partially extended When the Johnson Bar stopped in transit immediately switched the three position up off down landing gear switch to Off Regarding Johnson bars have a 1960 250 Comanche with the landing gear Johnson bar between the seats The Johnson bar moves to the floorboards when the gear is up and almost vertically to the
150. r side brace Check figure 25 item 19 part 20829 00 or 22512 00 on the drawing Page 7 53 After removing this part for whatever reason they have checked it for cracks using a dye penetrant and much to our surprise have found some cracked ICS TIPS Chapter 7 Landing Gear and Brakes Page 51 of 103 got a recent call from George Adams ICS 08288 advising that after having his Comanche serviced prior to a planned departure on getting back into the aircraft the right gear collapsed On examination it was determined that this particular stud had broken off at that moment have not seen this particular stud but would guess that it had been cracked for some time prior to the failure So strongly advise that at the next inspection this part be checked don t wait for the 1 000 hour gear inspection When you have the aircraft on jacks it will not take long to do this and could save you an expensive repair bill NOSE GEAR DAMAGE We continue to have our aircraft damaged by some airport attendant using a tug to move the airplane This may seem like an unimportant happening but it can wind up costing you a great deal of money There are steering limit markings painted on the gear but usually the person on the tug is either ignorant of this or not interested If your Comanche has been parked by someone other than yourself suggest you inspect it very carefully before you start it This service letter applies to the twin but the
151. r the green light either one tells you the gear is down Have you asked your IA AME or LAME if he or she has checked the preload on all three gears If he or she says no or doesn t know it should be checked and adjusted if needed before it was flown Do you really Know how to put the gear down using the emergency method Let s say it s a very black night and maybe you are in IMC If you have been properly taught and practiced it enough you can do it with these conditions after a total electrical failure Be sure you have a good flash light with good batteries in the aircraft When you look under the emergency door do you know if everything is normal and in its proper place Your flight instructor would ve covered this very carefully when he or she checked YOU out in the Comanche Is the spring that holds the screw up when the gear has been disconnected in its place and properly hooked up If it s not don t fly the aircraft until it s repaired just received in the mail today the recording of some 500 gear up or gear related items in our Comanches It truly upset me as this cost all these people a lot of money In going through them in almost every case the lack of good maintenance or lack of knowledge of the pilot was the cause At least that s the way see it As said in a short article before this the granddaddy of gear warnings is coming very soon NOTES ON THE LANDING GEAR From the Tool Box of Maurice Taylor have
152. r the socket itself If it turns out that the limit switches and wiring are at fault use wires ICS TIPS Chapter 7 Landing Gear and Brakes Page 102 of 103 to bypass the switches one at a time until the culprit is located If the problem can only be simulated in flight this will involve a few landings We found the nose wheel limit switch to be our problem There could be more than one problem It appears that over the years the contacts corrode in the limit switches First determine which half of the system is at fault then use jumper wires to selectively eliminate portions of the circuitry to zero in on the problem Sounds simple It is Just calm down and take your time A careful logical approach will yield good results every time Good Luck ICS TIPS Chapter 7 Landing Gear and Brakes Page 103 of 103
153. rag strut is not as critical because it is driven by a clevis rod rather than Teleflex cables to reach the down and locked over center position Dick is correct when he says the best way to check Comanche landing gear while extended on jacks is no fore and aft free play in the nose gear and no transverse play on the mains If excessive play exists it is a relatively simple matter to install new bushings in the pivot points and maintain the six and one eighth inch 6 1 8 length in the drag link which is adjustable This adjustment should be precise because it positions the gear correctly in the up and down positions in conjunction with limit switch adjustment Piper in its infinite wisdom designed the bungee roller cranks which extend aft of the main landing gear trunion on the aft side of the wing spar so the right hand part can be installed on the left side and the left hand part on the right side with a little strong arming by a good mechanic lacking a service manual and parts catalog This happens because the mechanic ICS TIPS Chapter 7 Landing Gear and Brakes Page 18 of 103 incorrectly believes the bungee is only to assist the gear up and locked in conjunction with the up lock solenoid on the transmission housing under the floor have made sketch A showing the bungee roller crank in the correct position when the gear is down with an arrow showing the direction of rotation through approximately 90 when the gear is cycled up Sketc
154. re attempting any adjustments For the Twins Follow instructions in Service Manual section 7 46 items a b c and section 7 47 items a b c and again paying attention to NOTE under item b This will ensure the Push Pull Cables and Push Pull Rods are adjusted properly For some reason these items are never mentioned yet am sure that most all mechanics know about these important adjustments If the mechanic working on your aircraft does not have a Service Manual or use a Service Manual or have access to a Service Manual there is no way he can make these adjustments without reference to the Service Manual These adjustments should be performed at each 1000 hour inspection or when the landing gear has been removed and reinstalled Safety Safety we cannot be too safe where lives are concerned and for the preservation of our Comanches A NOTE OF CAUTION Remember that over the years Piper has made these Service Manuals The page numbers may and will vary but the sections and paragraphs remain the same You just need to pour over the Service Manual more carefully and be sure you have searched diligently enough to secure all the information for gear adjustments JAMMED GEAR EXTENSION Readers of the Flyer may be interested in an experience had recently in Twin Comanche ICS TIPS Chapter 7 Landing Gear and Brakes Page 92 of 103 will have to set the stage On a trip back east we overnighted in Buffalo NY noted that m
155. reserved recommendation Once a mechanic has installed it it will not be hard next time the first time is a drain since the adjustment of the limit switches must be redone and it takes some real figuring as well as really fine work in installing wiring and matching the wires correctly found the old wires having been patched were now impossible to identify correctly to the old connection points also found an original switch that had the wires tightened down too hard and was cracked this would have occurred at the Piper factory and replaced it All switches were dirty and difficult and needed time and attention This aircraft is a very clean plane yet the original wiring system was anything but clean as learned because it was 35 years old and was just plain worn out This was a big factor in the labor time also installed the wire holdouts from Webco which with Matt Kurke s system are a real winner The end result is that installed new wiring from the fuselage to the limit and squat switches cleaned and adjusted or replaced all contact switches removed the wiring from the pivot point and located them through the Webco holdout brackets so the wiring doesn t get tweaked every time the gear is retracted and for about 595 in Matt Kurke s parts and Webco s holdout brackets another 30 plus a lot of labor Well next time it won t take as long now have a safe system which will last for another 35 years or more The twins aft
156. results in some Comanches being at much greater risk of mechanical problems than others Since it is your neck and your loved ones and your airplane that is at risk a review of the Service Bulletin and Service Letter compliance is highly recommended have located the following list of SB s and SL s that apply to the Comanche landing gear system There may be others 1 Service Bulletin 164 addresses the problem of the nose gear door retraction rod being installed improperly It is very easy to create this problem anytime that the lower cowling is removed It is very easy to correct 2 Service Bulletin 187 dated April 15 1960 addresses a problem with landing gear safety switches and notes that Service Letter 314A details the corrective measures to apply 3 Service Letter 301 dated August 12 1958 addresses circuit breaker popping when the gear is being lowered It addresses a temporary expedient to assist the motor by applying hand pressure to the emergency gear extension handle while the electric motor is operating 4 Service Letter 314A dated June 8 1959 addresses the problem of the landing gear switch being inadvertently moved to the gear up position prior to take off A kit is recommended that causes the horn to blow when the airplane is sifting on the ground and the switch is in the gear up position 5 Service Letter 315 dated February 4 1959 addresses a problem with a misadjusted micro switch at the down lock mechanism on o
157. rication used at assembly time has often dried out and the cables become stiff and sticky There are several other reasons for stiff and sticky cables On occasion have found that at some time the sliding sleeves at the end of the cable have been lubricated with grease This causes dust to collect here and make a very sticky compound which rolls up between the tubes and effectively locked them together The other reason is that the cable may have had an excessive compressive load incurred on it during a landing where the gear has failed to lock down As you can see from the construction the inner core is not designed to support the landing loads of the gear system It can be seen that any compressive loads will tend to unwind the wires and steel strip which causes it to become larger in diameter This will seize it in the conduits outer casing The normal cable lubricated and in good condition should move freely with vend little resistance My method of lubricating the cables is by the use of the tool depicted in the schematic drawing This tool consists of a length of clear plastic thick wall tubing of sufficient length to encompass the end of the cable at full extension i e in the down position one end has a plug and inflation valve clamped into it the other end is clamped to the outer threaded boss of the outer casing The method use is as follows insane pra an ICS TIPS Chapter 7 Landing Gear and Brakes
158. rouble free service NOSE GEAR DOOR INCORRECTLY INSTALLED My C model PA 30 was in the shop for repaint The only items that were separated from the aircraft were the HF and DME antennas and the nose gear doors The rest of the aircraft was masked and painted in situ The job was completed and as things have a habit of going wrong decided to check the operation of the HF and DME in flight just to make sure the connections were not paint affected and that the sets would pick up the nearest stations Looking terrific in the new livery rotated selected up got transit light but no gear up light Checking the CB found it had popped Resetting caused it to pop again and a quick look in the mirror confirmed the nose gear was only half retracted At 200 feet and climbing reduced power to think this thing out as the tower called to advise that the gear appeared not to have retracted Selecting either up or down and resetting the CB caused it to pop The gear is nicely jammed halfway Tell tower I m moving out of the circuit to sort things out get out the emergency handle and engage it There is no way can budge it in either direction With maximum physical effort a manual extension is completed and a successful landing ensued What happened in the paint shop that could possibly cause that In this case the doors had not been replaced in the correct manner Taking the doors off putting them back on opposite sides jacking the aircraft
159. rt having the problem with the down and locked light And unfortunately the real source of the problem was not found and corrected until the left main failed GEAR FAILURE MISSING SPRING AND COTTER PIN For the last twelve years have flown the same PA 30 and thought that was well acquainted with the airplane That was before spent forty five sweaty minutes over Lakeland trying to make the emergency gear extension do its thing the way the ingenious gentlemen at Lock Haven proclaimed many years ago When the gear finally went down and had a green light and a reassuring look at the nose wheel in the nacelle mirror realized that the success of my efforts had not been due to cool and precise performance of published procedure or to prompt analysis of a mechanical malfunction followed by application of brilliant corrective measures As near as can say was able to get the gear down because have two big feet to push on the extension bar at the same time had the airplane pulling two or three G s Two pivot pins in the transmission release lever sheared off and because have always been a very lucky fellow It did not hurt the outcome that it was day light VFR had plenty of fuel on board and was too stubborn to scrape the pretty belly of 16Y on any runway Later with the airplane on three good solid jacks we discovered the problem The initial cause of failure of the electric gear actuating system to lower the gear was likely due to
160. runway 30 was the better alternative Runway 30 is usually the active runway and had undoubtedly made at least 95 of my day landings and probably 99 of my night landings on 30 So decided to use a runway where all the visual clues were familiar also told the tower that requested landing clearance for runway 30L the longest of the three runways wanted everything on my side made a normal approach to a soft field landing The touchdown was so soft and smooth that neither my passenger nor felt the mains roll on Our first indication that we were on the ground was when the nose started dropping have never made another landing like that in any airplane Shows you what concentration or fear will do Be Careful When Taxiing We taxied to my tie down have subsequently learned that was still at risk of gear collapse when was taxiing Even though the gear was down with a green gear light showing it is still possible for the gear to collapse now know that when the emergency gear extension is used it ICS TIPS Chapter 7 Landing Gear and Brakes Page 84 of 103 is very important to treat the aircraft very carefully on the ground It might even be better to stop the airplane on a taxiway and carefully tow it to a tie down Certainly it should never be taxied over rough ground grass or at any speed that might put side loads on the landing gear All s Well That Ends Well The problem was in the transmission Gears were br
161. s Use information furnished by the aircraft manufacturer in servicing your aircraft Keep switches landing gear wheelwell and adjacent areas clean and free of mud and debris Repair or replace damaged or missing protective boots Do not use oversize or recapped tires that may cause landing gear to stick in the wheelwell Keep shock struts properly inflated and the pistons clean Lubricate landing gear in accordance with the manufacturer s instructions Wipe off excess grease Establish a program for corrosion prevention and control INSPECTION ICS TIPS Chapter 7 Landing Gear and Brakes Page 77 of 103 During the annual 100 hour intermediate or progressive inspection cycle place the aircraft on jacks and inspect for condition rigging and proper operation including the warning system Follow the aircraft manufacturer s instructions for inspection frequency and procedures When aircraft are operated from rough surfaces or used for student instruction more frequent inspections may be in order After a hard landing or if the gear strikes an object while taxiing it is wise to inspect for damage Rigging may be affected and damage may occur by sharp turns at high taxi speeds by faulty technique during a crosswind landing or by taxiing off a hard surface into deep mud or snow Preflight inspection should include the landing gear system The AC concludes by suggesting we can substantially reduce retractable landing gear accidents and impro
162. s as shown There are continuing incidences of cracks in Comanche main landing gear housings To check for cracks remove the bolt securing the clamp and slide clamp clear of web Clean area in vicinity of hole and inspect for cracks visually with 10X magnifier of dye check If no cracks are found modify hole and web as indicated ICS TIPS Chapter 7 Landing Gear and Brakes Page 55 of 103 Main Housing Web z Radius and polish areas of web and hole as indicated by arrows LANDING GEAR TEST In the January 1992 issue of the Comanche Flyer page 5 there was an article relating to the P N 20829 00 or 22512 00 being cracked The big question is why should it fail In all of the print that have read regarding the Comanche landing gear have never seen any mention of what think could cause this failure To extend the landing gear by emergency means in the air the forward speed of the airplane will load the nose wheel sufficiently to where the manual bar may have to be used to get the gear to lock in the down position To extend the landing gear by emergency means while the aircraft is on jacks the same action is taking place without the air load to resist the action This is all happening if the landing gear is released from the full up position do not think this should be allowed to happen and have seen it done a number of times The total load is being exerted on this part mentioned in the article As we all know a stead
163. saved my aircraft from a wheel up landing and gave myself another lease on life PROPER DOCUMENTATION OF LANDING GEAR AD 77 13 21 Larry Clark A amp P IA ICS 10059 Yesterday completed a pre buy inspection of a nice 59 250 Comanche and as went over the logbooks to check for any overdue AD inspections once again found improper entries for the landing gear inspection AD 77 13 21 As Maurice Taylor has said many times the landing gear on the Comanche is very reliable and trustworthy so long as it is properly serviced and inspected to ensure that tolerances are maintained within the factory limits In all of the Comanches that have inspected including my own PA 30 have yet to find the correct FAA approved entries for the landing gear inspections and bungee cord replacements I m sure that there may be some logbooks out there that are correct but haven t seen one to date Let s first look at the text of the AD and determine the required actions NOTE This is not the full text of the AD To prevent collapse of the landing gear after manual extension a Accomplish the inspection described on page 3 of Piper Aircraft Corporation Service Letter No 782A dated March 21 1977 and replace components exceeding the specified wear limits or an equivalent inspection and replacement procedures approved by the Chief Engineering and Manufacturing Branch FAA Eastern Region b Inspect the main landing gear bungee cords for frayed protec
164. t breaker marked landing gear motor with the master switch on Move the landing gear selector switch to the up position and the horn should sound with throttles in any position if your bird SN is after SN 24 656 If the horn does not function have it repaired before flight The green light should remain on during this check Above all replace the gear selector switch to the down position and then the landing gear motor circuit breaker to the on position GEAR WIRING Here s a landing gear tip some of you Comanche owners may find useful My landing gear would not retract After making two visits to a mechanic he finally found those five wire leads to the landing gear safety switch on the left landing gear The switch itself and the solenoid on the interior firewall were at first suspects but functioned perfectly Of the five wires two were broken from flexing and a third was hanging on by a strand The mechanic spliced all five wires and applied clear rubber silicone caulk to isolate the wires reduce the possibility of shorts and to promote better flexing If Piper had used proper wire and design in the first place this trouble would not occur but there are many practices in aviation as cheap and shoddy as in the automotive world first noticed trouble when the gear would not retract so if you ever have that problem check those wires leading to the safety switch very closely GEAR TRANSMISSION BROKEN WORM SCREW One night
165. t circuits are separate so that if one does not work the other will tell you when the gear is down But most important of all use your landing checklist every time GEAR WARNING HORN MODIFICATION The July issue of the Comanche Flyer had two excellent articles on avoiding gear up landings One was by Mark Pullmann in the Insurance Corner Landing Gear article and the other by Maurice Taylor in the Is the Gear Down article Both asked Does the horn work and secondly Can you hear it If the aircraft has had a proper annual the gear horn has been checked for operation and sound This check is done with the aircraft in a hangar up on jacks The horn is a simple mechanical device directly equivalent to a Model A Ford horn It is fairly loud in the hangar but not really that loud in flight The horn is mounted behind the panel on the firewall and is probably closest to your ankle As mentioned in the above articles the widespread and proper use of David Clark type headsets further reduces the likelihood of your hearing the horn in flight Wiring a tone generator to the gear horn warning switch and then feeding this signal into the audio system has been suggested as one solution to the problem had an opportunity to take a demo flight in August in a new Porsche Mooney and found that the gear horn is mounted in the overhead just beside the cabin speaker and directly in line with the pilot s ear There is no chance of missing the warning T
166. t go down at this point don t remember why He put it down using the emergency method and after a short roll out the gear came up Inspection showed that the springs were on the wrong way causing the gear to come up If you have had the inspection done on your aircraft look it over to be sure that everything is together properly want to thank Wayne for being so observant on the new aircraft We are also showing one page from kit F761 082 so that you can see how it should look ICS TIPS Chapter 7 Landing Gear and Brakes Page 69 of 103 Link 81262 92 Reinstall Drag Link Cross Brace As Shown Existing Spring Link amp Lugs E gt 7 ya y Nose Gear RE B See Sketch Cc Strut Housing Assembly A See Sketch B Bracket 21868 00 pa See View D D On Sketch C Upper Left Nose Gear Drag Link Spring 13098 00 FIGURE 1 Existing Switch Spring Installation View Looking Down Mounting Bracket DINO Drag Link Cross Brace Gasket Seal Ring Q a W W y J SECTION E E W Nut USAF 356 820 Lug C Washer Lock Washer Seal DETAIL 2 Link Switch Installation PA 24 180 PA 24 250 Bolt AN3 5A Washer AN960 10 Nut MS20365 1032C Bushing 80012 06 Nose Gear Down Lock Spring Installation Sketch A KIT 761 082 PIPER AIRCRAFT CORPORATION LOCK HAVEN PENNSYLVANIA SECTION C C GEAR STUDS Maurice Taylor ICS TIPS Chapter 7 Landing Gear and Brak
167. t looks nearly impossible to put back together the way it was So think of it like a puzzle with a kind of trick solution 5 Before you start make sure that there are no burrs on the clevis pin heads and that the clevis can pass easily through the holes in the bushing and the red arm assembly Dress out the openings in all these parts with a drill bit if necessary Take a small piece of 4 test monofilament fishing line and put it through the eye in the clevis and tie a small loop about one inch in diameter Cut off the excess Repeat this process with the other pin Put both pins and their loops inside the holes in the drive shaft tube 6 Next put the bushing over the drive shaft tube and center the holes over the openings in the tube With a small 2 inch piece of safety wire with a tiny hook bent on the end go inside the tube and patiently fish out the loops of fishing line through the holes one on each side Slide the red arm assembly over the tube and feed the fishing line loops through the holes in me phalanges from inside to outside 7 Atthis point you are pulling the clevis pins through the holes in the bushing and the holes in the red arm assembly the outside through the bushing and the flange using the fishing line as your guide You may need to make gentle alignments with an ice pick to insure the clevis pins come through easily Pull the pins through the openings to where the eye in the clevis is showing Engage the eye of the clevis with
168. t ours for the first time the other day while checking out the brake system found a large elongated hole where the bolt passes through the bracket that holds the handle in place ICS TIPS Chapter 7 Landing Gear and Brakes Page 9 of 103 Piper had installed a 1 4 inch bolt through two thin sheets of metal and after a few hours 2 200 of pulling the hole was elongated allowing the handle to rub on one side wearing it almost through Four rivets hold these sheets in place and these removed Using the removed sheets as a template made two new ones out of 1 8 inch aluminum installed these with 6 32 screws and locknuts with the heads on the inside You have to use a bolt 1 4 of an inch longer for the handle also found the brake cable was frayed where it ran over the bottom pulley The cable is hard to remove due to the cotter pins used to keep the cable on the pulleys The keys are hard to remove and even harder to replace so be prepared for a fair amount of work or expense for the labor to replace GEAR DOWN LIGHT No Green Gear Light We also had no gear horn but that was caused by another problem read on however it did help lead me down the wary path This problem has been with me since my plane was obtained about three years ago The first attempt to solve the problem was to ohm out the wiring It checked out OK Next step based on the schematic in the service manual was to look at the microswitch in the nose gear Con
169. tact cleaner was sprayed in the switch Now Notice to other Comanche Flyers Our gear switches 65 model are self contained Epoxy and spraying cleaner was useless and wasteful Therefore check the type of switch your plane has Things went along intermittently until its first annual While discussing the light and no horn warning problems with our A amp l we found out that the horn didn t work because the thin aluminum band that rings the vibrator had been kicked once and dented so the vibrator was bound up and no longer free to move Now with a new light on the problem one thing led to another and the cannon plug on the firewall was disconnected cleaned checked re soldered and put back together The intermittent gear light continued until one day turned on the navigation lights and there were no lights Investigation with a VOM led to me taking apart the entire switch unit that controls these and panel lights The switch on our plane has three sets of two contacts Of the six contacts four were worn and were refinished by soldering over them The rocker switch that makes contact with the six contacts was cleaned with emery paper Upon reinstallation the gear light is much better 95 success guess and the navigation lights work just fine May add this point that the schematic supplied by Piper did not exactly match our switch so my advice is don t believe everything one reads One should always make their own drawing as things are d
170. tally gear up is much preferable to landing with one main gear down Although this discussion is pretty much academic with Comanches because of the gear retraction design this decision must be left to the PIC ICS TIPS Chapter 7 Landing Gear and Brakes Page 97 of 103 If this checklist is ever necessary even partially have the equipment checked Don t fly with poorly adjusted switches etc We d like comments on possible error and on making the checklist shorter MAIN LANDING GEAR CONDUITS CONSTRUCTION AND LUBRICATION CROSS SECTION M L G RETRACTION CABLE ONE HALF gt LEGEND Wy TT E aol I A BC DE FGH A Swaged Threaded End B Inner Push amp Support Bearing C Outer Cover Sleeve D Inner Push Rod E Inner Cover Sleeve F Inner Flex Cable G Swivel Ball Joint H Rubber Dust Seal J Castle Nuts K Main Outer Cable Body L M N O P Part making up outer Flex Cable L Spiro Band SleeveM Coil Spring N Spiral Wound Wires ACW O Spiral wires Wound CW P Flat Spiral Band Wound CW Q R S T Parts making up inner Flex Cable Q Flat Spiral Band Wound ACW R Spiral Wires Wound CW S Spiral Wires Wound ACW T Solid Wire Core KLMNO P QRST Recently have had several requests for advice on the feasibility and method for lubrication of these cables without removing them from the airframe Notice in the cross sectional drawing that the construction of the conduit is robust and complex As ill
171. tension everything will look normal in the transmission compartment but the gear cannot be pushed over center Request the tower to inspect the main gear head on and look for any slight angle in either gear The nose gear should be inspected by a side view Draglinks are not visible in flight from the ground Item 10 specifies a partial gear landing because you can t have two inoperative gears with stripes full travel and no visible broken components In item 11 we propose to land without a green light and without attempting manual extension if our gear stripes are full travel and tower reports all gears down Manual extension will only unlock the gear making matters worse We propose to avoid crosswinds because these create side loads on the gear But we do think you should be alert for possible gear collapse anytime the gear light is not green Do not ignore that green light If Gear Stripes Not Full Travel In this case you have most likely burned up the motor or blown the gear motor CB due to high resistance from cold grease or blockage in the gear train We propose to complete the extension by electrical means if at all possible and our first step is to get the airplane stabilized with full flap at a low airspeed to reduce the air load on the gear We chose 1 3Vsf roughly 80 MPH on the 250 model as a reasonably slow airspeed because that is FAA approach speed with familiar handling characteristics We next troubleshot the 585 electrical po
172. termine how much of this was due to bending and how much due to lubricant motion but these are somewhat academic to our principal practical concern We are after a quick easy method of checking the overall system for total accumulated wear a method usable by anybody anyplace with simple equipment Our 20 20 hindsight made us wish we had thought of this before the mod instead of afterwards But at least we now have a further index for checking the health of our gear on the next annual and if any of the rest of you wishes to do the same on your birds we can soon have a pool of data that might prove to be quite valuable Having done all of the above and with our annual completed we flight checked our bird It is difficult to be objective when you are emotionally involved in something but it did seem to us on ICS TIPS Chapter 7 Landing Gear and Brakes Page 22 of 103 first gear retraction that the operation was quieter than it had been before On first gear extension we also found it was quieter and the clunk we usually felt as the gear went into down and locked position was still there but it was markedly quieter than previously SUMMARY We suggest and recommend to all our fellow members these items Standard practice on gear extension help the gear into down and lock by hand and feel for the clunk At each annual and any other time you have some doubts about your gear perform these checks 1 Total current drain a With recordi
173. the gear The light did not come on said to the guy with me that thought we may have a wheel not locking called the guys on the ground to let them know of a possible problem and to ask if they would take a look which wheel wasn t down and locked as flew by over the runway They agreed was very familiar with the emergency procedure and the amount of space that should be between the gear handle and the wheel well The handle was perfect But checked and locked it anyway by hand But no light As came over the threshold of the 2 500 foot strip for a fly by at 120 mph the cockpit filled with smoke decided to land without finding out which wheel wasn t locked The next day went in to find out what had happened and found that the linkage for the right wheel had an all thread rod with a nut on both sides like a clutch on a car one nut had worked its way loose then the other went the other way and the wheel was sliding on the linkage rod with no way to lock it had them add a safety wire to this setup after it was fixed and readjusted The factory does not call for a safety wire The odds are slim but that s all it takes Things could have been worse over a couple of little nuts The smoke was caused by the gear motor burning up because one limit switch didn t shut it off because the wheel was never down all the way and locked The mechanic said that the smoke probably wouldn t have gotten much worse but didn t know that at th
174. tive covering breaks soft areas and replace cords exhibiting these conditions In addition replace cords every 500 hours in service or every three years whichever occurs first c Repeat paragraph a at each 1 000 hours in service after the prior inspection and repeat paragraph b at each 500 hours in service after the prior inspection or within one year after the prior inspection whichever occurs first First and foremost your mechanic must have a copy of Piper SL 782A in order to check the landing gear for wear limits Do not let anyone who does not have these specifications directly at ICS TIPS Chapter 7 Landing Gear and Brakes Page 67 of 103 hand or does not have experience with this inspection touch your landing gear Many gear failures occur after an inexperienced mechanic has disassembled and incorrectly reassembled a Comanche landing gear The ICS has go no go wear limit check kits available for members to use that will help determine wear limits on the various landing gear parts An entry in the logbook of Replaced all MLG bushings does not meet the requirement of paragraph a A correct entry should read Inspected landing gear in accordance with AD 77 13 21 para a and Piper SL 782A and determined to be within specified limits Remember it is all three landing gear assemblies not just the Main Landing Gear MLG What I find in most Comanche logbooks are entries every three years that the bungee cords were re
175. to the moving armature to amplify the vibrating sound The trick is to adjust the contacts for solid and reliable operation with the loudest sound Adjust the contacts only 1 4 to 1 2 turn each time and make sure the locking nuts are tight It is a rather critical adjustment but a few tries should do it Make sure the contacts are clean and free of any build up prior to adjusting Also remember that the supply voltage is more nearly 13 8 volts when in flight and allow a little adjustment margin Then after reinstallation put the aircraft on jacks and check the wiring and operation of each landing gear micro switch the latter can be adjusted as to operating point It may be a surprise to some but it has nothing to do with MP It is mounted to operate when the pilot s throttle lever just behind the panel is moved beyond a certain point LOW BATTERY EFFECT ON LANDING GEAR Recently had a gear problem evidenced by a popped circuit breaker as the gear reached or nearly reached its upward position Each time the breaker was reset it immediately popped A mechanic put it on jacks and after extensive recycling on 2 separate occasions was finally able to duplicate it but could not find the cause Some friends and examined all the Tips re gear ICS TIPS Chapter 7 Landing Gear and Brakes Page 23 of 103 problems and put the plane on jacks recycled it again We finally adjusted the micro switch on the right main however even after that it popp
176. ular intervals from now on and will be more certain that if have to use the emergency gear system it will work NOSE GEAR WORN BELLCRANK AND BUSHINGS Items overlooked in a series of cheapie annual inspections have a way of snowballing and becoming ultimately very expensive A case in point When took my first hard look at my Piper Comanche a 180 model discovered that the nose gear steering bellcrank Piper P N 21768 00 showed evidence of peening on its cam faces If you ll look at the accompanying photographs you can see the distinct wear points on the cam s and on the steering arm bushings Piper P N 14976 which were worn to hourglass shapes and showed evidence of not turning The steering arm bushings function as rollers on the bellcrank s cam faces ICS TIPS Chapter 7 Landing Gear and Brakes Page 30 of 103 According to the Piper Comanche service manual these bushings ought to rotate with a slight drag The book actually calls out several dash numbers of the part representing several diameters which can be used to obtain proper adjustment It is evident that as wear of the bushings progressed the excess clearances were enough to allow peening or hammering of the cam faces due to increased play in the nose steering A couple of my otherwise inexplicable swerves on the runway are readily excused on the basis of this wear Less explicable is the ongoing lack of inspection and maintenance during the 23 year life span of t
177. uld not let the gear extend when we tried to lower it to land ABNORMAL GEAR OPERATION NTSB accident briefs on Comanche landing gear problems over a four year period indicate two cases where the gear transmission was separated from the aircraft four cases of disconnected cables and or rod ends two incidents of gear train blockage and one torque tube arm failure Although these occurrences are unusual there is no basis for assuming that they will not happen again The abnormal gear operation checklist which follows therefore covers both simple and unusual causes for gear malfunction Although the checklist includes owner s manual recommendations by Piper it is not approved by either Piper or the FAA nor is any such approval likely In as much as the FAR s specify the pilot to be in command the responsibility for its use is yours Items which you may consider unusual are therefore preceded by the word consider We cannot command your aircraft We are merely presenting argument as to what we believe is the best course of action If objections or improvements exist we would like to know It can be revised The checklist assumes that your transmission has been painted with red alignment stripes See Gear Operations Read each item completely before taking action If the specified conditions of an item do not apply proceed to the next item Items should be completed in specified order If the item states proceed to manual extension go direct
178. ully retracted position The more obvious ones are worn gears in the retraction mechanism lack of or too heavy lubricant for cold weather operation weak circuit breaker These problems can usually be overcome by helping the gear motor by pushing down on the emergency gear extension handle as the gear comes up Another not so obvious trouble can cause the gear to fail to retract all the way thereby causing the motor to overload and blow the breaker The hydraulic brake line is fitted through a loop on the landing gear fork It usually has freedom of movement through this loop or is positioned so that as the gear retracts the brake line folds inside the wheel well In cold weather if the brake line gets stiff it can sometimes become trapped between the gear door and the wing and not fold entirely into the wheel well Since the gear door can not close entirely the breaker pops And one more cause came to light just a few days ago The wheel well lining screws came loose and let the wheel well lining fall partially out of the well When the gear came up the wheel smashed the lining back into the wheel well in a not too graceful manner The irresistible force met the immovable object and pop went the breaker Take a tip from one who has had it happen Manual extension of the gear does not always lock the gear in the down position Upon landing the manually extended gear can collapse A good thing to do it you have a co pilot is to have him put his left
179. use your check list back of access panel A good autopilot or co pilot in the right hand seat can sure help the situation Usually you can take as much time as you need FAA GIVES GOOD ADVICE Glenn Plymate ICS 02658 In preparation for this special issue much research of existing publications was conducted to see if any addressed landing gear problems Choir member Michael Dolin uncovered a little known FAA document Advisory Circular 20 34D Prevention of Retractable Landing Gear Failures Written in 1980 it has good information and advice for preventing landing gear accidents A synopsis follows AC 20 34D begins with citing retractable gear accidents that occurred in 1979 That year there were 1 002 retractable gear airplanes involved in accidents Of these 106 were landing gear accidents Human factors were the cause of 67 of those accidents and 39 were caused by ICS TIPS Chapter 7 Landing Gear and Brakes Page 76 of 103 mechanical technical failures The AC suggests the number of retractable gear accidents can be reduced with deliberate careful and continued use of a checklist and proper maintenance HUMAN FACTORS There were 67 accidents attributable to human factors call it pilot error categorized as Neglected to extend landing gear 38 Activated gear failed to check gear position 12 Inadvertent retraction of landing gear 11 Retracted gear prematurely on takeoff 3 Extended gear too late
180. ustrated this conduit consists of an inner flexible core and an outer flexible casing with a rigid sliding sleeve and a flexible ball joint The inner core consists of a solid center core wire which has six separate wires spirally wound around it in one direction and twelve separate wires in turn spirally wound around those in the opposite direction Around all of this is wound a flat steel strip spirally wound around this again in the opposite direction again ICS TIPS Chapter 7 Landing Gear and Brakes Page 98 of 103 This inner core is then swaged into a solid rod at each end of the cable and passes through an inner tube and bush assembly At the end of the rod is a threaded area to which the rod and spherical bearing is attached To this threaded end an outer sliding sleeve is attached to seal the sliding surfaces The outer casings of the conduit has an inner core constructed of a strip of flat steel spirally wound in the opposite direction to the steel strip wound on the outer of the inner core This augers for a smooth operation Around this steel strip are some more steel wires which are wound around in one direction followed by a further set of wires and spring wound in the other direction These wires are individually separated by cotton type threads which effectively seal the conduit flex This outer section of the conduit is then swaged into a thread boss at each end as depicted in the sectionalized drawing Over the years the lub
181. ve aviation safety by being self aware knowing our airplanes and applying good maintenance practices COMMENTS The FAA s sample shows that about 10 percent of all accidents involving retractable gear airplanes are gear related with causes about two thirds pilot error and one third mechanical If such an AC applied only to the Comanche fleet the ratio of gear related accidents would probably be much higher Pilot error would probably be higher too based on what we ve seen on recent accident causes Gear system problems appear to be the leading cause of Comanche accidents and that s why this special issue is devoted to the landing gear If a Comanche landing gear advisory circular were written today the advice given by the FAA would still be fully applicable Use a checklist Know your airplane and maintain it properly Preservation of the fleet depends on it THE 1000 HOUR INSPECTION Bill Creech ICS 03423 In our discussions about the maintenance requirements of our landing gear the 1000 hour inspection is frequently mentioned want this article to be a discussion of the importance of this inspection a bit on some of the techniques involved and ways that the owner can assist the A amp P to complete same This article is NOT intended to be a How to instruction and should not be used as such If your A amp P is a qualified Comanche mechanic he ll certainly have the skills necessary welcome questions or comments from your A amp P
182. velop Once you have decided that you must lower the gear by the emergency procedure be sure to follow the procedure on the back cover of the access panel for your airplane There are some slight differences in the different models Hopefully you have gone through this procedure while the airplane was on jacks during an annual inspection or some other maintenance procedure Probably the most important step is to reduce your speed to below 100 MPH As you probably know from one of Maurice s Seminars he says 90 MPH is better and am sure it is Although getting the twin slowed to 90 MPH kind of leaves it hanging on the edge With a couple of exceptions all the people have had in my classes who have had to lower the gear by the emergency procedure have said that slowing the airplane to 100 MPH then raising the Motor Release Arm allowed the gear to free fail down and latch over center with the green Gear Down light coming on and an uneventful landing They did not have to touch the handle at all Be sure to check that the Transmission Retract Spring is connected in your plane This could prevent the gear from freefalling into place if not connected have found at least a dozen airplanes where the spring either was not connected or missing completely In one case an enterprising mechanic had used a four inch cotter key which made installation easy but would not have retracted the transmission and ball screw if the gear had to be lowered
183. visible Turn the bungee and tool to screw the fixed roller assembly in Screw it in all the way and then back it out one turn This allows the fixed roller assembly to rotate slightly and stay aligned with the pivoting roller Reinstall the pivot roller on the gear arm with the washers in their correct position The bolt should go in freely a slight adjustment of the adjustment nut may be required Either lower the gear slightly or turn the adjustment nut to facilitate removal of the tool Now remove the duct tape from the fixed roller and bracket It may be left on the bolt if it is folded back and not interfering with the bungee roller Congratulations one down and one more to go When you are done you will be an expert at Comanche bungee cord replacement PUMPED UP STRUTS Increasing air pressure in landing gear struts has little to do with landing qualities Gas oil struts on Comanches are always fully extended in flight and will touch down at the same time whether they have three inches or six inches of exposure when sitting on the ground The angle of attack change is effective only when the nose gear is compressed on the runway ICS TIPS Chapter 7 Landing Gear and Brakes Page 40 of 103 GEAR DOWN LIGHT A My 1964 Twin Comanche had a gear down green light out problem similar to that described in your most recent issue After changing all of the electrical parts in the system we finally found the problem in my airplane a worn
184. wed outward you will need to straighten them with a large pair of pliers The consequence of them being bowed out is that the sleeve or release tube cannot slide forward completely to uncouple the torque tube from the gear drive shaft This will effectively prevent you from manually lowering the landing gear during a real emergency I finally got your attention But the real acid test is to put the plane on jacks like at the next annual and test the emergency gear release arm to see what happens If it is difficult to disengage the torque tube and even more difficult to hook it back up then likely a problem with bent links has occurred It should be fairly easy to do the acid test and if the gear extension system is not working smoothly now is a better time to fix it than when in the clouds REPAIRS ICS TIPS Chapter 7 Landing Gear and Brakes Page 65 of 103 A The links The most common problem by far is the links attached to the red arm being bent Not only can they be bowed outward but can be bent fore and aft so that the approximate 110 degree angle the arms make could be compressed to 100 degrees If after straightening out any bowing sideways you are still are not getting a good opening below the sleeve is not sliding forward enough to allow access to the groove or slot in the shaft you may need to bend or change the aforementioned angle to improve this access and thereby allow the drive shaft to engage and disengage easily with
185. wer in steps 2 and 3 in item 4 we reset the breaker and made another try at extension this time with physical help on the handle Step 5 proposes that you now consider holding the breakers in for 8 seconds while attempting to lower the gear again with help on the handle The reasoning behind this item is that the gear resistance for whatever reason and we have reports of jammed gear doors is enough to blow the breakers manual extension may not work either Before repeating the procedure we specified a delay of five minutes for cooling purposes Holding a CB closed may appear controversial but is standard airline practice in solving emergencies ICS TIPS Chapter 7 Landing Gear and Brakes Page 96 of 103 If this procedure moves the stripes to full travel but no green light step 6 directs backtracking to item 8 on the first section and completing the remainder of that checklist If we cannot get the stripes to full travel burned out motor our only remaining option is to try manual extension Don t give up Manual Extension If you have followed the checklist in order you are still at 1 3 Vsf with full flap for the 9 emergency extension Items 1 through 3 follow the aircraft manual Items 4 and 5 reflect the experience and recommendations of members Step 6 reminds us to go back and conduct a circuitry check in an effort to get a green light Again we would like a tower inspection Item 8 reminds us to hold the extension handle firmly
186. wheel cylinders lately it might be in order for you to do so NOSE GEAR SUPPORT CORROSION Here is something that should be brought to the attention of all Comanche owners While installing a new engine in a 400 Comanche the asbestos wrapping around the engine just above the mufflers and exhaust pipes was removed for inspection The covered tubing was found to be rusted half way through severely weakening the nose gear support have since seen another 400 mount that had resulted in so much corrosion that the nose gear mount failed on landing resulting in major damage suggest that everyone check under these wrappings and if necessary have your A amp E repair or reinforce the tubing as was done to mine ED It is not recommended that asbestos or any kind of wrap be applied directly to the tubing as moisture is trapped and corrosion as described will occur A piece of metal held off the tube by Ya inch will stop the effects of direct heat radiation GEAR CIRCUIT BREAKER On the matter of the L G problem spoke about The problem started as no gear up action after a takeoff The relay worked the circuit breaker was not popped but no action occurred As it is an older PA 30 decided to replace the motor pro forma With aircraft on jacks with new motor installed still no action Leaving the gear position switch in UP position pulled the circuit breaker out The gear motor worked while the circuit breaker was being either pulle
187. y tires looked a little soft The book says 42 psi for the mains but mechanics don t seem to fill the tires to that pressure even though I ve got a red painted sign on the wheel covers Please inflate to 42 psi So wrote the message on to the line crew s work order The next morning gave the plane a careful pre flight and off we went toward Indianapolis Preparing to land at Eagle Creek Airport was amazed to find that the landing gear wouldn t go down This had never happened before The circuit breaker popped when the gear was about halfway down on several tries thought of holding the breaker in but thought that might burn out my gear motor or do other damage thought knew all about the Comanche manual extension system knew that after you use it you re supposed to have the airplane put on jacks the gear inspected and the gear motor reconnected That would mean a weekend in Indy but our daughter Sue lives there so the stay would be pleasant and relatively economical went through the extension procedure according to the book but Mabel and together couldn t get the gear past the half down position Suddenly the whole affair became serious To make a long story short after getting advice from others and trying several things was able to man handle the gear down Later we found that one of the wheel covers had not been replaced properly when the tires were inflated and it had become jammed in the wheel well which wo
188. y load will not fracture a part such as this nearly as fast as a sharp striking load The part mentioned is not designed for such treatment Side loads from cross winds fast taxi turns and the like will result in what the part is designed to experience It is my opinion that the service manual should contain the warning that the landing gear should never be released from the full up position when checking the emergency gear operation Run the landing gear down more than halfway prior to releasing the gear and allowing it to free fall ED We concur If the gear are released while the aircraft is on jacks one or more assistants should hold the gear and allow them to ease down gently and not allow them to fall precipitously ICS TIPS Chapter 7 Landing Gear and Brakes Page 56 of 103 NOSE WHEEL BRAKES It is most important that the ground to flight rigging of your Comanche compliment each other Does your aircraft become decidedly Squirrelly or skip and swerve at the transition period of ground run to full flight This would be noticed more likely in a nil wind still air situation where you would expect a smooth transition into the flight regime If you do not attain this expectation it is likely that your aircraft is not rigged correctly It is most desirable that your aircraft runs straight down the runway with all the wheels and the rudder in line with the longitudinal center line of the aircraft As the flight surfaces become effective
189. y understand if the gear transmission and other parts of the gear were not in very good condition as the bungees would not be doing their normal job that the gear will not go down by the normal method But why couldn t it be put down by the emergency method The reason could be that the push pull cables conduit are working too hard Or maybe the pilot who hasn t been properly trained and really doesn t know all the steps ICS TIPS Chapter 7 Landing Gear and Brakes Page 73 of 103 to put the gear down Please be sure you know this procedure very well from a qualified instructor Another problem that is very common is the missing or unhooked transmission retract spring Just now as was typing this got a call from a member stating that the Comanche that he just bought had no retract spring The spring is located in the landing gear transmission well and raises the landing gear transmission jack screw to prevent the jack screw from dropping down and interfering with the landing gear mechanism during manual extension of the gear With the spring missing it possible that when you go to put the gear down by the emergency drop down method it simply won t go down See S L 447 THE COMANCHE LANDING GEAR Larry Larkin The landing gear on the Single and Twin Comanche type aircraft is a very simple mechanical design It contains an electric motor and transmission to supply the actual force required instead of the pilot having to manually raise

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