[Prickle]

No, the pilot can depressurize the aircraft at high altitude.

In such a case, the emergency oxygen masks for passengers will drop, but those are only rated for 15 to 30 minutes.

After that Oxygen runs out, assuming the pilot maintains cruise altitude above 25000ft, everyone onboard will lose conscious via hypoxia within 1 minute, and be brain dead within 15 minutes.

No one (except the pilot) would be alive to see the plane crash.

Pilot can also re-pressurize the aircraft after 30 minutes, and breathe fine. Pilot oxygen masks are meant to last for at least an hour.

[akira2501]

It's more insidious. At high altitude the drop masks don't provide enough pressure to maintain consciousness for their full rated duration. It's expected that pilots will descend very quickly after a depressurization event to at least 14000 or below. If he stayed at high altitude the passengers probably went unconscious quickly.

[weweersdfsd]

Yes, for those interested in this scenario, check Helios Airways Flight 522. I think that's what happened with MH370, except that the depressurization was deliberate. Most likely a single pilot stayed alive and functioning in the cockpit, eventually repressurizing the aircraft.

Perhaps the pilot's goal was to hide all the evidence as well as possible, to create a perfect mystery. Then a controlled ditching would make sense, although it kind of failed considering the debris which eventually reached Africa.

[JumpCrisscross]

We only have a clue where it might be because Zaharie likely powered “the AC bus back up…Unbeknownst to him, the satellite communication unit starts to acknowledge the satellite again. This is his one mistake — but it’s a forgivable one, as hardly any airline pilots knew about this system feature before the disappearance of MH370” [1].

Without that, debris would only hint at somewhere in the Indian Ocean, probably.

[1] https://admiralcloudberg.medium.com/call-of-the-void-seven-y...