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Landing Gear

I'm out of the loop for conduit installations. The following is for reference only, not intended to imply I still do the installations.

If you want me to install your conduits or landing gear wiring harnesses please read this for the description of your work portion of the CONDUITS [click] installation, and/or this for the WIRE HARNESS [click] installation, and Contact me; see also the "Migrant Worker" link for any planned trips.


Landing Gear Conduits.

The conduits seem to be the hot topic so we'll cover it first.

Likewise landing gear transmissions are a hot topic; they have their own link.

Conduits - These are the main landing gear retraction system push - pull cables. The nose gear uses a push - pull rod.

The real way to check those conduits is just like the SM states. Disconnect both ends and check for freedom of movement. Because it’s a pain to do all the work to get there, at the very least disconnect the conduits and nose gear at the gear ends and check movement of both conduits using the manual lever. However it’s difficult without experience to know what too much or correct resistance feels like. And keep in mind, without the “load” of the gear on any conduit you will get a false indication. The “load” will exacerbate a problem in the curved area where the wear occurs; each conduit makes a 90-degree bend under the spar. One good note, if you do the suggested method and find a problem, you haven’t wasted any time. Why - because the access time can be converted into conduits replacement time. Count on a whole day to do it correctly, that means the entire landing gear adjustment procedure. Then one would ask the question, “Why not “invest” that time in an upgrade – new conduits”. See the logic? Hopefully resistance to replacing these critical components will diminish.

As one would guess I get a lot of inquiries about the conduits and their "resistance" as measured using the torque adapters. Note - see the ICS tool loan program page. The reports are even passing the prescribed test, the 30 CB opens near the up-limit. It's the conduits. I've not been informed ever of a torque test failing; tell me if you have - details?

Note - Comanche Gear does not hold a PMA for these conduits; that belongs to Webco Aircraft. Their P/N is W455-180; about $400 each [cheap in my opinion - good guys Webco]. The conduit supply from Webco is periodic; they have a standing order from their supplier. Since these are a popular item you had best plan ahead; they may not be available if you call them too late in a purchase cycle.

I know that I blab a lot so bear with me on this. I'm pro-active concerning landing gear maintenance, so if you phone me be prepared to get an ear-full. An ear-full of reasons why you should just do it; when were these push-pull cables lubricated? 1960, 1965? Another justification; replacing the conduits will offer the opportunity to examine the entire retraction system; if you find additional problems count it a blessing. Those potential problems newly discovered and properly remedied are an asset to the security of your retraction system; and the log book and maintenance records. This will instill confidence in you and a future purchaser.

installing the cushioned clamps and hardware
conduit installed and safety wired
Twin Comanche crossover clamps' orientation
View from the wheel well; conduit & mounting bracket

The above photos are found in the manual I've written as described below. I've performed 48 of these conduit installations until my rotator let go again [3-rd time] and every hint learned is conveyed in this manual. FWIW I was an engineer at IBM and one of my responsibilities was writing engineering reports. This KNACK for writing is partially derived from that experience; and as supported by positive feedback from purchasers of this manual.

Installation kit and manual description

Click on the cover page above

for a description of this manual and components included with the manual purchase. Click here for page one of the above manual.

Someone suggested that I change the name of this manual to, "Landing Gear for Dummies"; not a bad idea. I am writing another manual covering the setup procedures and adjustment aspects involved in the 1000-hour AD 77-13-01.

 

FBO kit

Click on the photo above for description of the FBO tooling and parts components available for purchase.


BUNGEE CORD INSTALLATION PROCEDURE

Click on the link above for a procedure Incorporating Maurice Taylor's file.

See also following below - landing gear bungee rollers.

The bungee cords have a shelf life of 5 years out of direct sunlight and heat. The link below shows how to figure the date of manufacture by the color code

AC 43.13-1B CHG 1, SECTION 9-4 b, TABLE 1


Landing Gear Bungee Rollers

While replacing the bungee cords be prepared to find seized bungee rollers; and after 54 years of misunderstood service I bet that many of them are seized.

Bungee arm and roller

Click on the photo above for the proper installation of these rollers, and a repair description if you have frozen rollers.

Note - this photo illustrates an improper installation of the roller on the bungee arm.


Main Landing Gear Assist Springs

Click Here

Click on the above photograph for information about this spring and its replacement procedure.

The photo above illustrates two issues, a MLG spring that hasn't been replaced as required, and the bolt [see finger] is installed backwards.


As you might expect I offer a couple “kits” to replace these springs.

$55.00 Basic kit contents for replacing the MLG assist springs.

And the $82.00 super-duper version, includes EXCHANGE-ONLY cadmium plated spring swivel assemblies.


The 1000-Hour AD.

I have written an instruction manual to cover this task; 71 pages with more information than you probably want to know. Lots of color photos, assembly drawing inserts, pages of part numbers utilized right down to the cotter pins. $100 and I guarantee it will educate you and your mechanic/technician.

  • 1000-hour AD 77.13.21 You already have or can easily obtain a copy of this AD. The contents of this link are my recommendations for better understanding of the scope of this critical operation; there is more to it than you think. Referenced in this AD is SL-782 which is addressed below.
  • TOOL LOAN for R&R of the mount bushings at the aft ends of the nose gear drag links. Includes instructions with photographs, tool components, reamer, and flex hone. $25 - another bargain that will save you grief.
  • SL-782B AMOC - Alternate Means of Compliance to SL-782. We can thank our fellow Comanche enthusiast Mr. Gregory L. Wilcox for his efforts to correct this oversight. Reasoning: the AD 77.13.21 stated SL-782, not 782A and not 782B.
  • Hans Neubert, from Kah-li-forn-yah [he's on the right - you're left - in the photo], has produced and sells a DVD covering the inspection portion of the above AD. Boy am I a lousy photographer, I'll get a better one when he's not looking; sorry Hans.

Drag Links exchange program.

Overall this is related to the AD 77.13.01, Part A. Specifically I have removed this AD service from the list of Migrant Worker services; it has been just too involved for me to deal with in a remote location without the proper equipment that is required to perform this service.

However I'm still developing the components program; it's going to be quite an involved project but may also be a real time-saver if you do not have an experienced shop available to perform this service. This service will have the option of cadmium plated steel components, see below. Stay tuned or call for an update.


20768-001 and 20768-002

Click on the photo above for a description of which airframes this component fits. I bought all of Piper's inventory; if you need a new one call me. See also the parts link. No used serviceable available at this time.

I also have cadmium plated serviceable links for the heavy airframes; 260C P/N 25046-000, 400 P/N 22577-000, and twins P/N 22577-000 and 25046-000. As of 02/01/2046 I have 2 of these links remaining; when they're gone that's it until owner-produced.


Piper drawing

By popular request above is shown a modified insert from a Piper landing gear assembly drawing showing the order of parts in this area. The beveled washers referenced are not used on the 260C, 400, and twin Comanche; those are non-beveled and a different part number. The notes in RED are mine.


 

Available stuff

 

A complete compliment of cadmium plated exchange steel components related to the landing gear is usually available; the above is just a sample.

This should be considered when refurbishing the wheel wells or other opportunity.


 

Details added

Here is a sketch I'm using for reference; it shows the roll pin and drive screw part numbers, and nose gear springs' new part number.

I wish this was a better scanned image for you; I can't improve its quality.


Side brace support bracket. Click here for the brochure.

non repairable
Supports brackets
This one is pretty ugly; who in their right mind would attempt to "fix" a loose fit with a punch?
A different set of brackets after repair.

The side brace stud fitting assemblies pictured above have an Airworthiness Directive addressing the cracking of the side brace studs; see AD 97-01-01 R1 - a 1000-hour cycle irrespective of any part's source.

More to consider; notice the wear mark [shine area] at the radius of this side brace stud. The flange of the stud never makes contact with the face of the bushing; not good. This condition exists because the stud's radius is not compatible with the bushing's chamfer. The cure is to enlarge the chamfer in the bushing - click the above photograph for more.
Measure the diameter of the bushing to assure proper fit in the side brace support. Click on the above photograph for a video of an improper fit.

 

 


Landing Gear Strut Housings.

includes modified brackets
includes modified bracket

Pictured is S&B Industry's repair to a left side "heavy" strut housing. This specific housing is for the "round" switch version; the rectangular switch version gets converted to this configuration and requires a modified landing gear wiring harness which I can also provide. Here are some of the strut housing part numbers referenced: 20752-012, 27053-004, 27052-013, 27053-05, 20752-008, 20753-000, 20752-009, 27053-000, 27053-001.

S&B Industries repair to a right side "heavy" strut housing. This repair solves the cracked strut problem; read strut crack

Click on the photo above to see the opposite view.

I no longer stock these repaired strut housings; I have pissed off Bruce at S&B Industries so you will have to suffer the down-time waiting for him to repair your strut.

I do have a pair of the later struts 27053-000 & 27053-001 as used on the latest PA-39, and in the service kits which are NLA. These struts are properly refinished in Matterhorn white and have the correct brackets [cadmium plated] and new placards included. I have installed the orifice tube which has been disassembled and cleaned, also included is the strut seal kit and cadmium-plated installation hardware.

 

 

 

Strut [oleo] housing; these are sometimes incorrectly called "Trunnions". FYI - the word "Trunnion" appears one time in each of the Single and Twin Piper Comanche Service Manuals; in reference to a bushing [item #31] in the nose gear strut housing.

  • The infamous strut crack and how to reduce the probability it will become a large problem. See the following link immediately below.
  • Inset - From Piper assembly drawing showing detail of the bracket installation at the strut housing. The bracket is the attachment for the MLG assist spring. The MLG assist spring is supposed to be replaced at every bungee change.
  • Photo #1 - It's easy to spot the crack if you know where to look.
  • Photo #2 - New and old style strut housings.
  • Photo #3 - A really lousy landing makes for a bad day too.
  • Photo #4 - This one was terminal for a 400.

Related discussions.

  • Adjustment suggestion - V I P down-lock limit switches. I would bet that this down-lock switch adjustment procedure is not well understood; a slight misadjusting here will allow the gear to be un-safe, i.e. not "down and locked" over center. I have encountered this misadjusted condition even on new harness installations; it can lead to a "gear collapse". I wish for all to be aware of this so shout it from the rooftops.
  • SL-315 - Landing Gear - “latest inspection and adjustment procedure” circa 1959.
  • Amber light failure - The amber light is the landing gear gear-up indicator light.
  • Green light failure - See also "wiring diagrams".
  • Resetting the landing gear transmission after manual extension - an easy method and explanation.
  • Effective length discussion - If reading this smokes your circuits don't blame me; it wasn't easy to come up with this solution.
  • Initial effective length confusion - See above.
  • Conduits - Is this what you call "Conduit Denial"?
  • Brake hose routing photos. See also the discussion about main gear doors in the "landing gear doors" link.
  • Can the push - pull conduits be lubricated?


Here is a cute one sent to me by good-guy Chris Kuyoth

 

 

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