Moving GA Aircraft by pulling on the prop
 

Is this ok? A very experienced CFII/Mil guy told me to never use the prop to relocate a plane as it "was one of the weakest points". I think he was referring to the likely possibility of not pulling in the exact axis that the prop "pulls" from. i.e. there would be some up/down, left/right pressure that over time would cause problems.

Went to rent at the local FBO and watched the line guy pull the 172 out of the hanger by the prop and it triggered my CFII's warning. Interestingly, this 172 has chronic oil streams leading from the prop hub up and over the cowl.

Thoughts from the smarter folks.............................

Another issue is that the pulling force would be applied to only a small part of the prop, whereas normal operation distributes the force along the whole prop. Similarly, you wouldn't want to pick up the airplane by its wings, even if your hands were strong enough to do it.

In 1200 hours of SR22 flying I did, with all movements in/out if the hangar were prop pulled/pushed. I never saw an issue with it. No mx items came up even remotley related to props or governers. Fwiw, they were 2 brand new aircraft, 600 hours put on each from new when I was there, 3 blade composite props. In fact, it was common to have little to no oil loss, except on real, real cold starts. Pretty routinely only needed to add a quart or two over the 50 hour oil change period.

True, but I doubt your pulling with 110 horsepower either..

Don't they jack up planes by their wings?

There is absolutely no chance of pulling on the prop will hurt anything, with one exception: don't pull at the tip of the prop. If you do, the prop will act like a lever and give you a mechanical advantage that will put a huge force near the hub that might damage it.

Stop and think about it for a second, what pulls the airplane through the air? The propeller obviously. It's designed to take a lot of pulling force, but not a whole lot of sideways force, so try and minimize that by pulling close to the hub with both hands.

Also, thinking that using your hands will damage the prop itself is not correct. Have you ever smashed your head on one? Ask a line guy who has been on the job for anytime longer than a month how hard those props are. Even the wooden ones. The only way you will hurt it is if you beat it with a hammer.

They do jack airplanes by the wings, but you'd had better know the proper area to do it. Otherwise you will punch the jack through the sheet metal. The point is almost always right under the wing spar.

Absolutely no issue whatsoever...just pull close to the hub.

We have had two separate incidents of cracked (micro cracks) in the hub of our C-172 over the last three years. Both have been chalked up by our maintenance shop to pulling the plane by its prop. Although we think some of our pilots were pulling further out towards the tips in order to turn the plane easier. Much more understandable then pulling right at the hub.

The real kicker was the day we picked the plane up from having the latest hub replaced the mechanics grab the plane by the prop to pull it out of the hangar, right after telling us not to do it. Needless to say that didn't go over well and they ate the repair cost.

"Don't use prop blades as handles...it can do really jumbo-sized harm to a propeller if you use the prop blades as convenient handles for maneuvering the plane on the ground."
--McCauley Textron Co.

"Avoid pulling the airplane around by the prop. Yes, this seems the perfect solution to a vexing problem of how to change the airplane’s position without having to walk around and get the tow bar, but it’s worthwhile to make the extra effort. Neither the engine nor the prop particularly benefit from the loads imposed by horsing the whole airplane around."
--AOPA safety training, sponsored by Hartzell Propeller inc.

"... never push or pull on the prop blades. Forget what anyone has told you about pulling near the hub or the strength of the propeller. Aluminum blades can bend, and it doesn’t take much to put the blades out of track with one another."
--"Propeller Care" by Jeff Simon, A&P, author "The Educated Owner"

Mechanically you should be able to get away with it if you do it gently, symmetrically, and near the hub. It would be really hard to hurt the hub, crankshaft, or bearings (impossible really) but the prop could bend. But why risk it? Just get the towbar or push on the strut.

Also it might be awkward if a mag was hot for some reason.

Saw the aftermath of this once, hot mags. Pilot escaped injury but the plane crashed into a really nice Cessna 310 on the ramp causing major damage.