Experienced this in a R44 myself.
Look closely and you will see the mag switch key is already in the OFF position when he does his panel shutdown .
In other words he flew his short flight with mags "OFF" .
..... must have a poor ground or electrical glitch for it to even start or run in that position .... by default mags are always ON .... and it is by grounding L R or BOTH that turns them off
Starter button is on the cyclic or collective , normally the pilot will rotate the switch to PRIME on startup .... however this was 3rd flight of the day (warm engine) and (my guess) he pushed the button .... engine started without him realizing mags were switched off.
He realized it when he flipped the key tag to the side to switch mags to OFF and saw they already were OFF ..... thus the sheepish grin (video)
Pilots & mechanics often make sure switch wiring to magnetos is bulletproof .... but forget that the ground to frame is what does the work.
This type of electrical glitch is rare , but not unheard-of .... another contributing factor is that many helicopters are shut down by shutting off the fuel mixture , not by switching mags to OFF .... thus the switch never gets "tested" during routine operations .... fixed wings with a prop that acts like a flywheel can momentarily be switched OFF to test , but a helicopter cannot .
It was the plastic gear in the magneto it had stripped a few teeth ... on the 44 on one of my 22 expierinces it was the actual switch and a problem with the spring the 22 we turn they key like a car, and the on mag check take it back to mag 1 then mag 2 as part of the checks ... I may add it was a old 22 and it was possibly 18 years agoHello Greg,
Was your experience with a faulty Mag Key Switch or a faulty/intermittent ground wire?
As far as I recall it was a faulty earthing connection in the switch itself and periodically on shut down one set of mags was alive , we were not allowed to fiddle with it and the AMO had to fix it, it was a flight school aircraft so it was well usedThanks for your experience Greg ..... but was your switch problem related to the mag being LIVE when in the OFF position ?
I know experienced fixed wing mechanics who say ... "it is not as rare as we think" ... thus they are paranoid when ground handlers turn a prop by hand to clear a tow bar or whatever.
Yes Wayne , I think that would be a way to test for live mags.(snip)
In my mind, the only similary kind of test would be to place the magneto key switch in the OFF postion and then push the START button to see if the engine catches and starts.
Mostly I flew the 0435 also , great engine , some B47's had a key on the panel that we never used (always left on) , mixture control disabled (always full rich) ... -30* weather mechanics removed the spark plugs at night and put them in a coffee can on the stove ... in the morning pilots would help the mechanic install them .... our bodies were freezing and fingers burning installing them .My Bell 47-G3-B1 doesn't even have a key (it's a Lycoming TVO-435 instead of the old Franklin). To reduce the chance of theft, I have an extra circuit breaker in an unpublicised location, and I put a big bicycle U-lock around the cyclic and through the guard at the bottom of the left seat collective (with a red "remove before flight" flag, of course).
Actually 2 or 3 206's stolen and used in bank robberies in Louisiana and Texas, one was used to rob a bank on the base at Ft. Polk, Louisiana. I was flying one for Air Logistics that was stolen. Took a lot of inspections and component changes to get it airworthy again. Never did find any cash hidden in it after I got it back, but we did look.
"We" did once .... as a prank .... competition helicopter outfit in a small town .... they had landed on the outskirts and then walked to the local hotel-bar where they were hootin and hollerin all night.
My insurance company seems to think it's a risk. All sorts of flying machines in the southern border states used to get stolen to haul recreational pharmaceuticals across the border, often abandoned afterwards.
Knew a guy who did just that .... around 1978 the flight school had trained him on a 206A Jetranger ... spoiled kid , parents paid $30k for his basic 100 hr commercial rating .I'm more worried about some "hold my beer and watch this" type wrecking mine.