Malaysia Airlines Flight MH370: Why is it taking so long to find?
Likely scenario, if I'm understanding this right: catastrophic systems failure causes loss of radio, pressure, and navigation. Pilots, unable to communicate, turn the plane back toward Malaysia, as accurately as they can under the circumstances, which may include only a few seconds of useful consciousness. Plane continues to fly for quite some distance with no communications and nobody conscious at the wheel. Not sure of its exact heading, the search area could be enormous.
Alternatively, they were grabbed by Martians and are currently dining with Amelia Earhart. Or Amelia Pond. Or both.
At the first sign of preasure loss, the pilots are trained to don their oxygen masks.
And there's no way that plane could continue to fly hands off if it had suffered such a catastrophic loss of systems.
A 737 went down a few years back a loss of air pressure causing everyone to black out and flew on autopilot until it ran out of fuel and crashed but they were able to track it.
If the MAS 777 had suffered something similar it would have still be able to be tracked on radar as long as the transport continued to function.
The 777 is also a fly-by-wire aircraft so if the computer systems suffered such a fault as speculated about it wouldn't have stayed airborne.