Interesting byproduct of fire situations is smoke.
I observed a demo some time ago by a well known manufacturer of cockpit crew protective smokey environment vision enhancing equipment (it would have been much easier to just say the name but I guess I have to practice what we preach with the defacto advertising thing).
Seeing (or, actually, not seeing) is believing.
The speed with which a smoke generator can totally obliterate the cockpit visibility is the stuff of raised eyebrows.
The other day I had a domestic microwave with a transformer failure.
The kitchen filled with significant smoke in a matter of seconds. Standard IA (flick the power switch at the meter outside) killed the problem. Then a bit of trouble shooting to isolate which circuit .. when I found the correct one, the regeneration of smoke was a real eye opener.
A fire might
(a) burn out important stuff like wings and through hull services
(b) even burn the bodies after the crash
but the smoke will take control from you far quicker.
If you think that you can troubleshoot cockpit smoke in flight consider that Ansett, years ago, had a fire in the 727 sim. As I recall (and I may have the detail a bit skewed) it took the techs several days to find the source ....
As the aforementioned OEM's advertising bumpf puts it .. "if you can't see, you can't fly". Nice folk as well.