On the pull ;-)

[ROB. THOMASSON]

Way back when while learning to fly I was told not to pull an aircraft on the ground by the prop. This wasn't to protect the prop but in case the mag switch was faulty or on and the impulse mag fired spoiling your day! I thought this was under HSE legislation but a very qualified chap tells me this isn't so.
So does anyone know if this is an urban myth, an old wives tale or.......
Having actually had 2 mag switches go live over 30 years of flying I can see the logic.

[Chris Martyr]

Hi Rob.
I think that HSE reg's are a bit too generalised to go into aircraft related technical issues such as this and your mate is probably quite correct in what he says.
This is more in the territory of the Fed's and if you go to CAP-562 Chapter G [ground ops] para;3.1.1 they pretty much echo what we were all told back then and is still relevant now.
Although having said that, I always pull my Volksplane out of the hangar with my fingertips around the back of the prop hub and pull her along like a little dog. Fine for a small a/c , but you probably couldn't/wouldn't do that with a J3 or a Champ.
With an ign. system like the LeBurg electronic , I think you can be reasonably sure that the ignition is off, that is after all how I shut off the engine after its previous flight, by switching off the ign. like a car. But with a variable jetted carb which is put to ICO to shut the engine down , there is nothing to say that your mag's have both earthed and they may well be ready to kill/maim with inadvertent prop movement. Not to mention that funny old rotary switch still fitted to many older types which, if worn can still be connected when in the 'off' position.
Also, it can unnecessarily stress the prop blade if pushed/pulled.

[ROB. THOMASSON]

Many thanks for that.

[G-TERN]

I think the principle is like teaching a child that they should wash their hands after going to the toilet; they know they should - but don't always do so.....!

[Brian Hope]

I think the advice is generally good, for several reasons. The live mag reasoning is one, and the earthing doesn't have to be the issue, you could have left the mags on at the last shut down, or somebody could have been fiddling with your aircraft since you last used it - let's be honest, you don't always check the mags are off when pulling the aircraft out of a packed hangar.
There's also the issue of prop damage. Pulling from the hub is OK because the blades are thick and the trailing edge rounded. Farther out they are not so sturdy and damage could be done - I know we are all bright enough never to pull or push on the outer part of a prop blade but I've seen plenty who are not I'm afraid.
When you are on you own I know pulling on the hub is the easiest option, and if you know for sure the switches are off, better still if you shut down using the mag switches and know they are working, then who am I to tell you whether you should take the minimal risk. With two or more people, better perhaps to pull from a sturdy area on the wing tips.

[Ian Melville]

Actually Brian on some aircraft it is a bad idea to handle by the wingtips. The leverage applied by long wings can impose quite high forces on the wing root. Diamond Katana is one that springs to mind.

Each aircraft should assessed for handling as an individual, and handled accordingly by competent people. Many times I have seen the struts of high wing aircraft pull from mid-length

[Brian Hope]

Fair point Ian, I guess know your aircraft and where best to push and pull, and if helping on an aircraft you are not familiar with - ask.
Rgds, Brian

[Chris Martyr]

Diamond Katana is one that springs to mind.:

You boy,,,,,,,..Stop swearing ! [ ]

[Ian Melville]

Don't worry Chris, I have been reformed since I joined the LAA