[Tzfat]

The first two steps in an emergency descent are, don oxygen at 100%, then set the autopilot to descend to 10,000 feet or higher for terrain.

The theory you mentioned would not explain how it descended to 6,500. Depressurization on an Airbus is not subtle, believe me.

[randita]

So you’re saying that since it was a controlled descent, that would indicate that the pilots had the wherewithal (oxygen in case of depressurization) to initiate such a descent. And if they had the wherewithal to initiate the descent, why didn’t the descent stop at 10,000 feet or whatever altitude was necessary to clear the mountains.

[RayChuang88]

While I agree, but if the decompression happened really fast, the crew would have 15-20 seconds to react before losing consciousness, especially if both crew members were not wearing oxygen masks at the time the rapid decompression started. As such, I'm still sticking to the theory things happened so fast that while the crew was able to start an emergency descent sequence, they passed out with the plane only partly tilted down for an emergency descent. This may explain why the plane made what appears to be a "normal" descent straight into the ground in a controlled flight into terrain crash.

We should find out more once both the cockpit voice recorder and flight data recorder data are fully recovered and analyzed.