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View Full Version : CFI Pop Quiz #320 - Magneto

Chris Burgess
03-20-2006, 04:04 AM
If the ground wire between the magneto and the ignition switch becomes disconnected, the most noticeable result will be that the engine

A) will run very rough
B) cannot be started with the switch in the ON position.
C) cannot be shut down by turning the switch to the OFF position.
Friendly
03-20-2006, 04:22 AM
The engine can not be shut off at the switch or "C"
GyroRon
03-20-2006, 04:32 AM
c................
Aussie_Paul
03-20-2006, 04:48 AM
C) Gee, even I know that one.:eek:

Aussie Paul.:)
Rehan K.Janjua
03-20-2006, 11:44 AM
"C" is correct.
But "A" will also result if the ground wire is touching the frame or other metal parts.
Rehan.
Caribean_gyro
03-20-2006, 11:46 AM
I knoe for sure C
Paul_Zurawski
03-20-2006, 12:15 PM
Si....Ceeeee...(C)
B8MFlorida
03-20-2006, 02:32 PM
See................
birdy
03-21-2006, 02:18 PM
Just outa interest, wot sorta current is flown through the earth lead when you ground ya ignition??? [912]
I often flick the switch on and nuthn happens, and i gota flick like a loony to shift wotever is holdn the points apart.[ moren likely a spec o dust] This is a pain ina ass if i'm in a hurryed fuel stop.
A couple o times i just left it ideling when i fueled up coz i couldn't wast time friggn bout with it. And i suppose sumone will tell me this is a dangerous proceadure.
Chris Burgess
03-21-2006, 03:04 PM
The correct answer is "C". If the ground wire between the magneto and the ignition switch becomes disconnected, the most noticeable result will be that the engine (C) cannot be shut down by turning the switch to the OFF position. Reference FAA-H-8083-25

Always treat the prop as "Hot", ready to fire, which would be the case with a broken grounding wire on a magneto. I lost a prop on a "super MAC" engine once. It couldn't be shut down, even by physically grounding the magneto. It finally gave up after pulling three of the four sparkplug leads.
EI-GYRO
03-22-2006, 04:11 AM
What, no fuel cutoff ?????. ;)
Chris Burgess
03-22-2006, 05:47 AM
Good point EI-GYRO. The answer to your ???? is no.:( It was a 1987 Parsons tandem trainer and it did not have one installed. I found that when I shut off the fuel on a MAC, it still takes almost a minute to shut down. I think a fuel cutoff is a good idea though.