Fox News reported that according to the Chinese media, there were 160 Chinese on board, not sure about the other passengers, just that there were 13 additional nationalities on board..could be another Air France type of incident, a hijacking storming the cockpit, could be possible, but it would have had to take something pretty catastrophic for a plane to just fall out of the sky
Unlikely, as they'd have time to contact ATC if that were the case.
On Fox News with an interview Scott Hamilton an Boeing 777 expert stated could also be a Pilot Suicide...YIKES!!!