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 $395 each [$100-$125 less than Piper]. Occasionally I have Webco's conduits in stock and if I don't have immediate plans for them they may be available for sale to help someone out of a pinch. 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.

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 44 of these conduit installations 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.

Someone suggested that I change the name of this manual to, "Landing Gear for Dummies"; not a bad idea.

Click on the cover page above for description of this manual and components included with the manual purchase.

Click here for page one of the above manual.

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

Conduit email discussion - Is this what you call "Conduit Denial"?

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

New bungee cord replacement tool

BITS (Bungee Installation Tool System)

As a Comanche owner who struggled with changing the bungees on our plane for over 20 years, we decided to design the best bungee installation system around. First of all we wanted to make an installer tool that would remove the old bungee effortlessly. To do so, we made ours collapsible and therefore much easier to insert between the tightly stretched bungee halves. Once in place it is re-expanded to its normal length. Likewise, we wanted a stretcher tool that would make replacing the bungee on the installer tool a snap. We have also designed the stretcher tool with safety foremost in mind. Look at the Instruction Manual in PDF format and see for yourself.

Price $199 plus S&H

Contact:

David Clark A/P ICS #08592
2812 Millbrook Ct
Arlington, TX 76012
Phone 817 860 4393
Email  dave520@prodigy.net

Additional photos: Stretcher tool asm & Installer tool asm

Landing Gear Bungee Rollers

While replacing the bungee cords be prepared to find seized bungee rollers; and after 45 years of misunderstood service I bet that many of them are seized.

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 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.

$45.00 Basic kit contents for replacing the MLG assist springs.

And the $77.00 super-duper version, includes EXCHANGE-ONLY cadmium plated spring swivel assemblies.

• 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.

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.

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. New ones from Piper list for $725.28; availability unknown.

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.

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.

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.

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.

S&B Industries 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. Click on the photo above to see the opposite view.	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 usually have these repaired strut housings in stock; they are sold exchange-only with acceptable core.

• 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?

• Cleveland Wheel and Brake Service Guide

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