Lots of good info in all these comments but no one really knows yet. I’m sure they will pin it down. However a few comments noted the auto throttles will reduce power and bring the aircraft to an altitude 10,000 - 15,000 ft and allow pilot recovery from hypoxia.
But what is the result of a pilot suffering hypoxia for 2+ hours? Can you just snap out of it once you get a normal supply of oxygen or is there brain damage?
You are Dead
Steve, the automatic system I mentioned above would immediately descend an equipped airplane (not this accident airplane) to 15,000’ within 15 minutes from 40,000’ (even quicker if a pilot is able to extend speed brakes/spoilers during the episode). So, responsiveness after prolonged exposure would not be an issue in that case.
Perhaps somebody else could speak to the effects of long-term hypoxic exposure, but I imagine that there is a “point of no return.”
Above about 20K, you have just seconds to think logically, then unable to comprehend, then unconscious, then dead, all in a super short time. Higher the quicker it all happens.
I flew the CE-550/560 for 12 years. We never turned the pressurization off.
Roger, according to Wikipedia, time of useful consciousness (TUC) at 22,000’ could be as much as 10 minutes (normal ascent) or as short as 5 minutes (rapid decompression). At 35,000’, those numbers are 30-60 seconds and 15-30 seconds, respectively. And at 40,000’ the numbers are 15-20 seconds and 7-10 seconds, respectively. While unconsciousness certainly occurs quickly at the higher altitudes, many stowaways have survived several-hour flights in the mid-30s. I imagine the outcome isn’t as good after a couple of hours in the upper 30s to low 40s.