Nanchang CJ-6A gear-up landing at Oliver Airport BC [video]

[CFR]

Often the maintenance manual for specific aircraft will identify how to lift it. While it usually identifies jacking points, sometimes it identifies lifting points. (my AC is put together like a model airplane, the wing is one piece. To take it off, the body is lifted from the engine mount and a strap around the rear fuselage) Failing that, any AME worth their salt will be able to tell you where on the structure to lift and how to spread the load to prevent damage. Failing that, any rigger worth their salt with access to someone who has proper structural knowledge of the AC and/or via their own assessment of the structure, should be able to rig and lift the AC without damage.

Now I have a question. For an AC that is covered by insurance do you not have to first contact the insurance company and work with them on how and perhaps even by who the AC is recovered if it is not assessed as a total loss?

[tonyhunt]

.... a bunch of greying pilots ....

Careful, that describes most of us who fly for fun in Canada.

[Big Pistons Forever]

.... a bunch of greying pilots ....

Careful, that describes most of us who fly for fun in Canada.

Yah the ones who are not grey do not have any hair at all

[PilotDAR]

For an AC that is covered by insurance do you not have to first contact the insurance company and work with them on how and perhaps even by who the AC is recovered if it is not assessed as a total loss?

Yes, sort of. Your policy places upon you (the policy holder) the expectation to prevent further loss to the aircraft. If securing it, protecting it or moving it is reasonably necessary to protect it form further loss, or the company from further liability, some good judgement should be applied.

But, yes, in most cases, leave it alone until the TSB, Police, and your insurer tell you that you can move it.

[AirFrame]

True there are high loads on the prop but it only weighs 50-100 pounds hanging on the crankshaft.

??? So? In flight, the airplane weighs 2450 pounds hanging off the other end of it.

Your reply reminds me of people who tell you that you should never pull on a propellor to move an airplane...

[CpnCrunch]

??? So? In flight, the airplane weighs 2450 pounds hanging off the other end of it.

Your reply reminds me of people who tell you that you should never pull on a propellor to move an airplane...

Not quite. Your typical bugsmasher has a maximum thrust of about a quarter or a third of its weight. Some aerobatic planes have a thrust to weight greater than 1, but I think it's unusual.

https://en.wikipedia.org/wiki/Wayne_Handley

[triplese7en]

True there are high loads on the prop but it only weighs 50-100 pounds hanging on the crankshaft.

??? So? In flight, the airplane weighs 2450 pounds hanging off the other end of it.

Your reply reminds me of people who tell you that you should never pull on a propellor to move an airplane...

Haha and they'll tell you that if you do you should put your hands near the hub. They don't know what to say when I tell them that the highest thrust force on the prop is at approx. the 3/4 point along the blade!

I know the prop slides forward and back slightly. The only thing that could be hard on it MAYBE would be pushing the prop versus pulling (the normal direction of thrust). But I still haven't heard any convincing arguments to say you shouldn't push/pull a plane by the prop. I'll all ears though.

[crazy_aviator]

In a large turbofan engine,The centrifugal force is approx 100 TONNES per blade (fan) and the force outward of each turbine blade is approx 18 tonnes. All of these blades "float" on their discs ( are loose ) when static . The Centrifugal force on a propeller blade combined with thrust and twisting moment is NOT the same as pulling half way out on the blade in a fixed or CS prop, Moreover, when turning, the crank thrust face is seperated from the thrust bearing by a film of oil. Just like ignorantly picking up the A/C by thin straps and a tow truck, Pilots and AME s alike ignorantly handle props and other components. Ever seen a pilot/AME push down on the HOR STAB of a C-150/172 alone to pull it backward or turn it? Ever wonder WHY there is a SEB out adressing cracks in the FWD spar and elongated and cracked FWD mounting holes? There is much more uneven force on the CS hub components when trying to move an A/C forward by hand then there is when the Aircraft is in flight

[triplese7en]

All of these blades "float" on their discs ( are loose ) when static . The Centrifugal force on a propeller blade combined with thrust and twisting moment is NOT the same as pulling half way out on the blade in a fixed or CS prop, Moreover, when turning, the crank thrust face is seperated from the thrust bearing by a film of oil.

Can you explain this more? Do you have some references or images?

If this is true then I'd like to understand it and handle the airplane properly.

[J31]

True there are high loads on the prop but it only weighs 50-100 pounds hanging on the crankshaft.

??? So? In flight, the airplane weighs 2450 pounds hanging off the other end of it.

Your reply reminds me of people who tell you that you should never pull on a propellor to move an airplane...

Well you asked the question so we are trying to answer......

When an engine is running the prop forces are mostly parallel with the crankshaft. However if you put a strap around the crankshaft and lift, you are now putting a 90 degree force on the crank that it was never designed for. Not to mention engine mounts and airframe structure.

As for pushing or pulling on a propellor, not a problem but you do want to keep the load close to parallel on the crankshaft. Although pushing or pulling forces by hand will not approach the weight of the aircraft . You do want to be very careful handling propellors in the event a live magneto could cause the engine to kick over with a small rotation of the prop.

[iflyforpie]

All of these blades "float" on their discs ( are loose ) when static . The Centrifugal force on a propeller blade combined with thrust and twisting moment is NOT the same as pulling half way out on the blade in a fixed or CS prop, Moreover, when turning, the crank thrust face is seperated from the thrust bearing by a film of oil.

Can you explain this more? Do you have some references or images?

If this is true then I'd like to understand it and handle the airplane properly.

It's the same as rotor RPM for helicopters. Helicopter rotors must be in the green arc to pull collective, otherwise they will fold up and be destroyed. This is why after an engine failure you must dump collective right away--particularly on rotors with low inertia like the R-22--to prevent RPM decay.

You wouldn't try and lift a helicopter by putting straps half way out under each blade... would you?

As for the thrust bearing, no biggie. The thin film of oil is to keep it from wearing out when it is turning only.. you can pull on it as much as you want. But pull (or push) on the root of the prop blades only.

[AirFrame]

When an engine is running the prop forces are mostly parallel with the crankshaft. However if you put a strap around the crankshaft and lift, you are now putting a 90 degree force on the crank that it was never designed for. Not to mention engine mounts and airframe structure.

Makes total sense up to the mention of engine mounts... The engine mount does carry the load of the engine and prop, at limit g factors, plus safety factors, loaded perpendicular to the prop axis. Lifting on the mount shouldn't be an issue. Makes me wonder why they didn't use it for the CJ-6, although there is something odd about how those cowlings open, don't they go up and back, possibly blanking the top if the mount?

As for pushing or pulling on a propellor, not a problem but you do want to keep the load close to parallel on the crankshaft. Although pushing or pulling forces by hand will not approach the weight of the aircraft . You do want to be very careful handling propellors in the event a live magneto could cause the engine to kick over with a small rotation of the prop.

Exactly.

[triplese7en]

As for pushing or pulling on a propellor, not a problem but you do want to keep the load close to parallel on the crankshaft. Although pushing or pulling forces by hand will not approach the weight of the aircraft . You do want to be very careful handling propellors in the event a live magneto could cause the engine to kick over with a small rotation of the prop.

That's what I thought. As long as you're pushing/pulling along the crankshaft and not perpendicular to it I don't think you're doing any damage.

But pull (or push) on the root of the prop blades only.

I always do push/pull near the root of the blades. It's harder anyways to push/pull with your hands spread further out if you're doing it yourself!

[J31]

When an engine is running the prop forces are mostly parallel with the crankshaft. However if you put a strap around the crankshaft and lift, you are now putting a 90 degree force on the crank that it was never designed for. Not to mention engine mounts and airframe structure.

Makes total sense up to the mention of engine mounts... The engine mount does carry the load of the engine and prop, at limit g factors, plus safety factors, loaded perpendicular to the prop axis. Lifting on the mount shouldn't be an issue. Makes me wonder why they didn't use it for the CJ-6, although there is something odd about how those cowlings open, don't they go up and back, possibly blanking the top if the mount?

As for pushing or pulling on a propellor, not a problem but you do want to keep the load close to parallel on the crankshaft. Although pushing or pulling forces by hand will not approach the weight of the aircraft . You do want to be very careful handling propellors in the event a live magneto could cause the engine to kick over with a small rotation of the prop.

Exactly.

Sorry I did not make it clear....what I meant was by lifting up on the crankshaft places stress on the engine, crank, engine mount, and possibly the airframe. Lifting at where the engine mount meets the airframe structure however would most likely be fine. But you are right it could be difficult to hook up to the engine mount the way those cowlings swing back.

[PilotDAR]

Some planes are designed to make hooking up for hoisting very easy, others not. Obviously, like anything one would do with a plane, suitable skill, experience and training are vital. You would not let a person with no type relevant flying experience fly it, so why let a person with no relevant recovery experience recover it? Okay, if it's an emergency get it out of the way situation, you work with what you have. Otherwise, follow the instructions, employ an experienced person, who will use appropriate techniques.

It is possible that some aircraft have identified and maybe even marked hoisting points. It is a certainty that a crankshaft will not be one of them! I don't care how inconvenient the access to the appropriate lifting points might be, other than for emergency action, it's got to be better to go to the effort to access them, than to jeopardize the airworthiness of an engine with unusual loading.

Very simply, if you reviewed the defects column of the journey log, and read "aircraft lifted by crankshaft", would you fly it? It would not read right after it was done, so it can't sound right before it is done!

Or, as the lowest possible common denominator, would you want to come on here, and post "I directed that a plane be lifted by its crankshaft yesterday". Just imagine the ridicule!

[Doc]

Jacking and lifting points aside, most retractable gear airplanes are more or less, designed to perch upon Dunlaps, Goodyears or Michelins.......not their aluminum bellies. Food for thought. Zero sympathy here.

[The Mole]

All of these blades "float" on their discs ( are loose ) when static . The Centrifugal force on a propeller blade combined with thrust and twisting moment is NOT the same as pulling half way out on the blade in a fixed or CS prop, Moreover, when turning, the crank thrust face is seperated from the thrust bearing by a film of oil.

Can you explain this more? Do you have some references or images?

If this is true then I'd like to understand it and handle the airplane properly.

It's the same as rotor RPM for helicopters. Helicopter rotors must be in the green arc to pull collective, otherwise they will fold up and be destroyed. This is why after an engine failure you must dump collective right away--particularly on rotors with low inertia like the R-22--to prevent RPM decay.

You wouldn't try and lift a helicopter by putting straps half way out under each blade... would you?

As for the thrust bearing, no biggie. The thin film of oil is to keep it from wearing out when it is turning only.. you can pull on it as much as you want. But pull (or push) on the root of the prop blades only.

You are so wrong about helicopters. The manufactures puts an eyelet on top of just about every models rotor head. We use it all the time to lift the whole airframe, its how you get the transmission out. Its doesn't damage anything either. You can just put straps under rotor head to and lift it that way. Many have been slung off mountains sides like that. For reference a bell 206 can have 100lbs hanging off each blade tip, with out causing any concern. only on robbies you cant pull the blades down. You wouldn't put straps around the blades and lift the whole aircraft, it would damage the trailing edge, its not designed for that kind of load. But the blades also wouldn't snap. You can pull pitch on rotor system bellow flight rpm, the only thing that happens is the aircraft doesn't become airborne and the rrpm drops even more. When you do autos you pull the collective to the top stop when flaring onto the ground. Nothing folds up. Not lowering the collective in flight has nothing to do with the blades folding up...

[howard40]

Man this can be a rough crowd at times.
Remember until we forget the gear, we are still in the "those that are gonna" or "those yet to" or "those that might at any time" camp. The day you really know you WERE good enough, is the day you hang up the keys for good. Until then, be careful, and check it a few times, before you land, every time!
I woulda taken both upper and lower cowls off (easy on a chang) and lifted it in close to firewall on a few mounts with wide straps in several places , and put a bunch of the hangers around to work underneath it , the tail would need a lift, but not much of one . 3 or 4 fellas under the fuselage would probably be enought to lift it level , along with the straps on the mounts and the "wrecker".

[CFR]

Why isn't there a CADORS report for this incident?

CADORS entered today.

2013-10-11
Narrative:
TSB A13P0221: A privately operated Nanchang CJ6A (C-FTQW) landed gear up unintentionally at Oliver, BC. There was substantial damage but no injuries.
O.P.I.:Maintenance & Manufacturing Further Action Required:Yes

[pelmet]

More Nanchang problems in Oliver.



N75485, an American registered Nanchang China CJ6A, landed back in Oliver, BC (CAU3) after having completed the last sortie of the day for a war bird demonstration flight when, during the taxi back to the hangar, the aircraft struck two parked vehicles. The pilot was maneuvering to turn around when the right wing tip struck the back window of the first car. The aircraft then veered into the back of the second car and chewed into it with its wooden/composite propeller which was destroyed at impact. The aircraft was brought to a stop after striking the second ca