slacktide:
This entire argument regarding the autoignition temperature of aluminum and
CFRP is bogus from the beginning as it ignores thermal mass. Place a 2" thick
paper textbook and an empty aluminum beer can in front of a lit propane torch,
and let me know which one burns through first.
Hardly the same conditions, is it ?, as in your example, there isn't the
cooling effect of the outside air rushing by at -50C. The aluminium pan on
a gas stove boiling water is a far better analogy. Fact is, composites are a
good heat insulator, so would get little benefit from outside air cooling.
Of course, all bets are off for both materials on the ground, with no
cooling.
If such a minor fire can cause so much trouble and unknown level of material
degradation, one wonders why fire insulation wasn't fitted to the upper half
of the fuselage. One would think that it should have been mandatory with
such a heat sensitive material...