[onewhippedpuppy]

Originally Posted by AZ_porschekid

Hypoxia, what a ****ty way to go.

According to what I could find on Wiki, at 40,000 ft you have 15-20 seconds of consciousness before blacking out, enough for an experienced crew to don their masks. I'm not sure what altitude they were at when contact was lost, if lower they have more time. It would have to be catastrophic rapid decompression that either incapacitated the crew or was distracting enough that they disregarded their training. Plausible but again - what would cause catastrophic rapid decompression on an otherwise normal flight? Modern airplanes are pretty damn good, very rarely do they suffer from major airframe failure that isn't instigated by some form of human activity.