The strange thing is the situation of the crash. Weather report was fine and no storms in the area reported. No distress call and the plane on radar dropped 200 meters before disappear, again no alert and distress call. So it's unlikely a weather caused incident like Air France 447 crash. Also, the plane was at ideal safe zone ( way beyond the take off and landing risk stage). So it's either a mechanical or terrorist attack. If it's mechanical, it should be a major one to cause it disseminated in the mid air without time to make distress call; if it was a terrorist attack, the purpose was not to take over the plane, but just destroy it (like bomb or so). The other possibility is it was still out of the vocal communication zone form both Malaysia and Vietnam air control.