[Zhang Fei]

Based on reports of the pilots transmitting problem reports for 15 or so minutes, if it was a bomb, it was a very small bomb that did not destroy the fuselage. A merely small bomb with half-a-pound of C4 would have snapped the pressurized cabin in two immediately. From 40,000 feet, the debris would have taken less than a minute to hit the water. Did someone sabotage the plane? Did someone set a fire on the plane? Were incendiaries deliberately checked into the luggage compartment? All of these are possible.

There is also another possibility - sloppiness in maintenance. Some years back, Taiwan's state-owned airline - China Airlines - had a plane (a 747) that also broke up in mid-air. The cause was diagnosed as maintenance issues - parts were not replaced when they should have been, leading to stress cracks accumulating until they disintegrated the entire plane in mid-flight.

[GovernmentShrinker]

The pilots didn’t transmit anything after the plane was in trouble. Those were all automated transmissions from the plane’s systems. The last actual communication from the pilots was quite a bit earlier, and quite routine, just noting thunderstorm activity which is to be expected along that route.