One of the black boxes from Air Asia 8501 has been found. It should be a just a short while until the other recorder is found which will give a complete picture of the fate of the aircraft should they yield good information.
My speculation is that the aircraft wandered into a thunderstorm which then either compromised the structure of the aircraft, or placed the aircraft in a position from which the pilots could not recover before hitting the water. A stall scenario similar to the Air France crash over the Atlantic may have occurred.
It should only be a short while until more is known.