But why did the plane fly at 40,000+ altitude for over 20 minutes? That's the part that doesn't seem consistent with an accident unless it was somehow done in confusion.
Not sure this is quite accepted anymore. That's one of the early "facts" that's at least in question right now.
I read yesterday that military radar tracked it for 23 minutes flying between 43,000 and 45,000 feet shortly after communication was lost then descended quickly.
That wasn't from the information released weeks ago - seems more concrete now.
It would help if you linked where you read it. Some sites are currently reporting things from a week or more ago as if they're new.
As investigators continue to analyse satellite data in the hope of finding answers on what happened to Malaysia Airlines flight MH370, an industry expert said the plane spent 23 minutes at up to 45,000 feet – way above its maximum altitude – and rendered everyone unconscious from the lack of oxygen, said a report in British tabloid Daily Mail.
The plane's maximum service ceiling is 43,100 feet, but military radar had tracked the aircraft flying at between 43,000 feet and 45,000 feet shortly after the last communication from its cockpit.
"It was tracked flying at this altitude for 23 minutes before descending. Oxygen would have run out in 12 minutes (in a depressurised cabin), rendering the passengers unconscious," said the source.
An expert said although the 777-200ER Boeing aircraft has a maximum service ceiling of 43,000 feet, it can probably fly safely at even greater heights.
http://www.themalaysianinsider.com/malaysia/article/mh370-spent-23-minutes-above-maximum-altitude-may-have-caused-hypoxia-says
The exact amount of time was never reported before. That sounds too specific to be speculation.