Old Solution “How to Jack the Airplane”

[GAHorn]

I rec’d a query lately which asked “Where to buy a Jack Pad ? “

Here’s my suggestions for review:

https://www.univair.com/atlee-dodge/ces ... twQAvD_BwE

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https://www.aircraftspruce.com/catalog/ ... y=12226543

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And:

A "poor mans" jack point can be made from two square pieces of plywood (4" by 4") and a 6 or 8" C-clamp.
Simply take two pieces of plywood, one on top, one on bottom of the leg, clamp it with a large C-clamp...and using an ordinary hydraulic jack against the bottom of the "C", jack up the airplane. No damage to paint will occur if you clamp it tightly.

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[gfeher]

I have found that the jacking fixtures like the ones in the first two photos in George’s post will damage the paint on the gear strut unless you put a thin pad between the fixture and the strut. This is because the fixture slides up the strut a bit as you jack up the plane. I use a 10” x 10” (approx) piece of rubber from an old inner tube for a pad, but you can also use a thin piece of leather. The pad needs to be significantly larger than the mating surfaces of the jacking fixture and cushion all areas of the fixture that contact the strut. I initially tried bonding a pad to the mating surfaces of the fixture but it didn’t last long. Keeping the pad separate from the fixture works much better as it allows the fixture to move and adjust independent of the pad and strut. There needs to be a significant portion of the pad above the fixture as the pad tends to stay with the strut while the fixture moves up the strut as you jack the plane.

George’s “poor man’s jack” in his bottom photo is a great idea. Probably better than the steel jacking fixture. To make it even better, i would glue a rubber pad on one side of each of the plywood pieces. It’s probably not necessary though.

Just some thoughts.

[Bruce Fenstermacher]

I have used all three "jack pads George showed on 170s as well as many different aircraft. Our shop had the first two for the occasion when a Cessna type (not a Cirrus) came into the shop.

My go to and preferred method is the C-clamp and suitable wood. The C-clamp should be robust and better quality works better than cheap. Wood can be thick plywood or 2x4 but I like a 2x6 myself. You must really tighten the C-clamp.

[DaveF]

I use an engine hoist and strap. Here I’ve jacked, removed the wheel, then let the axle down onto the cribbing.

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[GAHorn]

In All Cases …be aware and vigilant as to how the airplane might be affected.

If a jack or hoist fails… How will that affect the airplane as it collapses or fails?
How might it affect other / nearby airplanes / objects ?

Jacking an airplane on one side will obviously lower the opposite wing …so clearance should be planned-for…. But what if the jack should fail or the airplane fall off the jack or support ? Will the opposite “rising” wing strike something unintended ? Or will the same-side wing fall upon anything? ?

And don’t forget that, once the airplane is on the jack or supporting “cribbage” ….that WIND can have a surprising affect on the airframe and take it Off the Supports !

ONLY JACK AN AIRPLANE INSIDE A HANGAR ! (and on a stabile surface….. soft ground can allow the airplane to “sink” into a position from which id may be difficult to recover.)

Never trust a hydraulic jack for sole-support while working on the airplane. Use Blocks, Cribbage, or Jackstands to support the airplane, Especially if one will be working beneath.

If an engine-lift is used, be aware that slippage or breakage from straps, ropes, chains, etc. may allow the airplane to settle upon the raised arm of the lift, offering an opportunity to puncture a wing or other structure.

Stand away and consider all aspects of the operation before jacking. BTDT

While on the subject, I’ve seen airplanes jacked or lifted by the engine mounts as a method to get both gearlegs up off the ground.
I”m not suggesting this is “wrong”…. but consider whether the structure is actually designed to support the amount of weight in suspension.
The stresses imposed on the welded-tubing, the rubber mounts (pads), and the stress applied at the firewall can be enormous. ….in-particular and especially lifting the airplane by the mounted-engine itself……and surely is not the design consideration, unless the mfr’ spcifically approves that method. (Has anyone seen Cessna approval for this method of lifting?)

Hope this helps.