Nose scissor disconnect

[Michael Bryant]

At a recent CPPP, it was recommended that we replace the cotter pin in the bolt that connects the nose gear scissor with a cowling safety pin. In an old thread here regarding disconnecting the nose scissor, Bill Creach recommends using AN416-2.

My IA indicates he would need a field approval to make such a substitution. Has anyone done this that would be willing to share the 337?

Thanks,

Michael

[Kristin Winter]

You might have trouble finding such as 337 as I think most IA's consider that to be a minor alteration and not a major one.

The problem with that modification is that you still need a couple of wrenches to undue it or snug it up. I would only do it if someone else was routinely moving my aircraft with a power tug that didn't pick up the nose. I am not going to break it with my hand tug.

[Michael Bryant]

Kristin,

Thanks.

The recommendation was not to disconnect every time you parked the plane, but to disconnect anytime you were leaving the plane overnight at an unfamiliar airport. If you were to either have the aircraft hangered or tied down outside, there is a possibility the aircraft could be towed by an FBO unfamiliar with the Comanche's limited turning range. With the disconnect, you need not worry.

As the very old forum topic advised (IIRC it was from 2002), you do open a can of worms. Is a 337 required? Can the owner/pilot legally disconnect/reconnect the scissors or is an A&P required?

Just trying to consider the options and see if there was a more recent view.

Michael

[Kristin Winter]

When I leave my plane with an FBO, I take a picture of the nose trunnion with my phone. They break it, they buy it.

[Michael Bryant]

A very good idea.

[Charles Schefer]

I have the nose scissor disconnect set-up. No 337.... and not because I don't want to file one, I file them all the time. The FSDO felt it was a minor alteration covered by AC 43.13. Same with the nut pate and screw conversion I did on the nose cowl to get rid of the fussy SouthCo fasteners - hate them.

I can send you pics later but... Kristin I am not sure what you mean regarding using wrenches. My nose scissor as it came from the factory has a castle nut and cotter pin. The nut is finger tight and then locked with the pin. If you wrench it tight it won't move freely as it is supposed to. I'm probably misunderstanding your point. All I did is replace the cotter pin with a removable lock pin that makes it easy to take off, and then un-thread the nut to disconnect. I do agree that I only do this when leaving the plane at an FBO. The "take a picture" point is a good idea but I'd rather avoid damage in any event, especially after I spent $25K and 5 grueling months of my time overhauling my landing gear!

Talk to Cliff Wilewski at Herritage Aero. He supplied me with the scissor disconnect set-up. I'll take a pic and post it later.

- Charles

[Charles Schefer]

As promised here is a pic. Note the only difference here from 100% OEM stock is the normal cotter pin has been removed from the castle nut and in it's place there is a locking pin that can be removed. This makes it easy to disconnect the scissor but you must be careful to not lose the three washers (one under the bolt head, one in-between the two scissor links and one under the castle nut. The thickness of the washer inside the link is used to align the nosewheel so it's important the washers always go back to their correct spot.

In the kit Cliff Wilewski provides, he includes extra bolts, washers, nuts, and also a little bracket that slots into the two factory towbar holes for the lower link to rest on when disconnected. I don't actually use that part, instead I have a set of bungies that work well with a bright yellow "Remove Before Flight" streamer.

- Charles

[N3322G]

Charles,

Interesting - thanks for posting. Our 1970 PA39 did not come that way.

Oh - stunningly clean - don't you ever fly it? or do you carry q-tips and clean it when you land - just teasing - I'm envious. I'd like 22G to be that clean but don't have the patience.

[Charles Schefer]

Thanks Pat, it's a labor of love and yes I do fly it quite a bit. I actually do have a large supply of Q-tips, and a variety of Meguiar's Wax (cleaner-wax, straight carnauba, and spray). I detail after every flight and keep a slippery coat of wax on the entire plane. It's not too bad if you keep up with it but it does take quite a bit of time I admit.

I'd be interested to see what the hardware was on your PA-39. As I said, for my 68 PA-30"B" this is stock other than the removable pin instead of the cotter pin.

- Charles