if you had a depressurisation, an engine failure, a cabin fire or
say a windscreen blown out (is that poss?) a high level birdstrike into the
windscreen (how likely could that be?) would you still stay on track and descend into the mountains?
Different type of aircraft, of course, and an unlikely scenario, but what about the British Airways flight that had a windscreen failure, leading the pilot to be sucked halfway out of the aircraft? Rapid depressurization, a very cold and presumably very busy co-pilot, and everything blowing around the cockpit. In such an event, it would seem that the co-pilot's O2 mask could easily become damaged or dislodged.