he "fire triangle" was replaced a number of years ago by the "fire tetrahedron."
Well, no, physics did not suddenly change a few years ago, the "fire tetrahedron" was always there. (we had firefighter refresher training on precisely this subject last month). I did not say
only three things were needed to support a fire, I just presented the three which supported my point. I don't think that opening up a discussion of the chemistry of pyrolosis has any benefit in a general aviation thread titled "parachutes".
Though a pilot is required to have a fire extinguisher in the cockpit, and that it's presupposed that pilot will use it there, if the circumstances dictate, in this forum, it is unlikely that pilots have extinguishing systems in the engine compartments. Therefore removing the fuel for an engine fire is the best option, and the first thing a pilot should be considering.
the engine still has oil. An oil fire is very difficult to control,
Indeed, hence my reference to
exposed fuel. For the engine types prominate in this forum, I would suggest that engine oil fires are very rare, and as there is very little the pilot could do if there were such a fire. Engine oil vapours are rarely exposed to heat and oxygen in concentrations which support fire.
may not be able to ground a magneto through the cockpit controls.
Yup, I agree with this statement, though I hardly think a live mag is a risk as a source of ignition for a fire. A lot of unrelated failurs would have occurr simultaniously for that to happen!
If a fire has occurred, one may nor may not be able to interrupt the field,
If one is flying an aircraft which meets the design requirements, the pilot has control of the alternator/generator field, so have no fear pilots, you'll be able to turn off the master, and remove that ignition source if you need to.
Yes, there are some very minor risks (combined failures) in aviation, that we just cannot mitigate. Let's discuss and mentor those risks we
can mitigate. Getting pilots here worried about engine oil fires and uncontrolled electrical sources foward of the firewall really has little value in pilot mentoring in my opinion.
We who certify aircraft designs pay a lot of attention to the flammability characteristics of an aircraft, on both sides of the firewall. Pilots should be reminding themselves, that although nothing is perfect, they have a lot of opportunity to make a fire situation less serious very quickly. Pilots must understand what control they have, and use it (firewall shutoffs, for example).
It would be unfair of me to suggest that aircraft fires do not occasionally occur, and that a few of those are not serious. But, a pilot who has prepared him/herself, has a lot to work with, to make the very least out of a fire in flight - prepare, and play to your strengths....