A and C
If the situation is serious enough that you feel the need to make a Mayday call then I would suggest the situation is serious enough to follow the POH emergency checklist which starts with Master Switch Off. Then as I said in my last post after an assessment of the situation you may elect to follow the POH procedure for restoring power which are designed to minimize the fire risk to make a radio call.
Just to be clear I consider a fire inside the cabin one of the worst things that can happen to a GA pilot. The cabin of your average light airplane is full of plastic and foam which will give of noxious fumes when heated, the small size makes it impossible to move away from hot areas and renders use of the fire extinguisher problematical.
So for me if I smell the distinctive harsh odor of overheated wires which will generally be the first indication of the potential of a progression to a full blown electrical fire is going to be the cue to take immediate action to take away the ignition source.
Personally I have trouble understanding the idea is that the first thing you do when you think you are in trouble is send out a mayday. D & D are not going to be able to do anything to immediately make the situation better and the first thing they are going to do is to start asking questions to find out what is going on, which is going to encourage a conversation that will eat up time and in the worst case allow the odor to smoke to fire progression to take place, something that can happen quite quickly. Once the flames have started you are in a very very bad place........
Finally electrical power is not required for safe flight for the average GA light aircraft flight. Frankly any pilot that can't handle the possibility of loosing electrical power, which of course could happen for many reasons, is IMO not ready to be flying on his/her own, especially with passengers. They need more training.
So to summarize BPF's bottom line. If I am flying around and I smell burning insulation or other smells suggestive of electrical mayhem, I will immediately follow the POH checks starting with the turning the master switch off. I will then asses the situation and if I feel that no immediate danger of fire exists consider using the checklist procedure to restore power for essential services only which will probably be confined to only one Comm and I will land at the nearest suitable aerodrome. Since an electrical fire is started by electrical power I simply will not take the risk of leaving the aircraft electrically powered for any length of time if I suspect the possibility of a serious electrical malfunction.
Last edited by Big Pistons Forever; 22nd Jul 2012 at 02:08.