Dani, I appreciate the point about the risk of fire being minimal in an aircraft and I would say it is even more minimal in a car. Most modern cars have an impact resisting structure around their fuel tanks unlike aircraft where they tend to be sufficiently strong to retain fuel and not much else.
The most common cause of aircraft fires seems to be when people over prime before start and there is a fire in the intake manifold which can blow back through the air filter. These are usually non-events if you keep cranking the engine to suck the flames in. The worst that will happen is that there may be damage to the air filter. If the pilot panics and stops trying to start the engine, he/she may be sitting facing a burning engine very quickly.
From what research I've done (not particularly extensive I must admit!!) it seems that man made fibres generally tend to shink when exposed to high temperatures long before they burn which is not going to be pleasant. When they do burn they tend to form a crust which also shrinks onto whatever is underneath it.
I fly a 61 year old taldragger. The fuel tank is above my knees and the fuel lines run aunder it to a Ki-Gass primer (prone to leaking occasionally) and down to the fuel selector valve on the floor. Given the age of the system there is a possibility of a leak. Just next to the fuel tank are the mag switches which have the potential to produce a spark when activated. So the ingedients for a fire are all there if attention is not paid to the integrity of the fuel system. All in all I prefer to have cotton jeans on when flying just incase I have to beat out burning avgas on my legs with my gloved hand!! I don't wish to sound paranoid but it's just another thing to be taken into account when flying especially ancient old aeroplanes. I will get around to getting that Nomex flying suit one day but I don't think it is a must have right now item.
