Swinging the gear

[konstantin_azarov]

Hi all,

I'm looking for some tips to make gear swings less scary. We've always done it at a condition inspection using our mechanic's underwing jacks, but even that feels pretty sketch.

Do you all just use the regular jackpoints + tail stand, or something else to stabilize the airplane too?

Best,
Konstantin

[DavidMandel]

Ha I think I know what you mean by scary, the whole plane rocks when the gear is extended or retracted! My IV-P actually does not have jack points installed and so we (an A&P and myself) have had to use a hand jack under each wing. Each jack has a few wood crates and a blanket on top of the crates which makes contact with the underside of each wing. We use an engine hoist to hold the nose up. Can't say if this makes it less scary but it feels stable.

[Robert Pastusek]

Konstantin
Your comment of “scary” pretty much describes my experience over the years with jacking an IV-P for a gear swing. Mine needs to have the fuselage 42” off the floor at the jack point to clear the swinging main gear.
As Dave Mandel suggests, I’ve improved the stability of the jacked up airplane by using an engine hoist to carry some of the weight and to plant the tail stand firmly on the ground. I’ve also asked a helper to hold a wing tip during gear extension/retraction to dampen the twisting motion of the fuselage on jacks caused by the independent, uncoordinated movement of the mains.
You must be careful to remove the engine hoist before lowering the main jacks.
Bob

[Tom Sullivan]

An added note of safety I perform to the first retraction. I never use hydraulic pressure to swing mine the first time. After ensuring 10" between the mains and the floor, I use a pry bar through the gear door and manually pop the safety pin (circuit breaker pulled, gear lever in the raise position) and manually swing it through the first time. If you are short on lift by even a tiny bit, the gear will raise the aircraft OFF THE JACKS during the swing. As you can imagine, that would be a pretty nasty action! Once swung through the retraction arc and verified plenty of clearance between the tire and the floor ( on both gear legs), I then perform a hydraulic swing in short stages the first couple times.

If you are uncomfortable performing this on jacks, welcome to the club. It's clearly a rather stressful action.

https://studio.youtube.com/video/Bt9j7DJNIxk/edit

Tom

[konstantin_azarov]

Thanks everyone, we did it some time ago without an incident.

This is what I ended up with for the tail stand (made from a HomeDepot jack stand, some 2x4s and plywood). It prevents the tail from moving both down and up. I think a similar jack that can be extended and retracted under load could eliminate the need for weighing down the nose. Honestly I didn't think that adding an engine hoist to the nose added that much safety - and on the contrary, if you forget to release it before lowering the main jacks the results may be catastrophic. It's probably much safer to just make sure that the tail stand won't slip.

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