A "very sudden and very violent" event is likely to be responsible for the loss of the missing Malaysia Airlines Boeing 777, according to aviation experts.
The aircraft was en route from Kuala Lumpur to Beijing when air traffic control lost contact some two hours into the flight.
No distress calls were sent from the aircraft, leading experts to assume that whatever happened to the plane occurred quickly and left the pilots little time to respond.
"Either you had a catastrophic event that tore the airplane apart, or you had a criminal act," said Scott Hamilton, the managing director of aviation consultancy Leeham Co.
"It was so quick and they didn't radio."
The plane is suspected to have suffered a sudden break-up, or a failure which caused a steep dive. Some experts say an act of terrorism may also be responsible.
William Waldock, who teaches accident investigation at Embry-Riddle Aeronautical University in Arizona, said the absence of a distress call "suggests something very sudden and very violent happened".
One of the first indicators of what exactly occurred on Flight MH370 will be the size of the debris field.
If it is large and spread out over tens of miles, then the plane likely broke apart at a high elevation. That could signal a bomb or a massive airframe failure.
If it is a smaller field, the plane probably fell from 35,000 feet intact, breaking up upon contact with the water.
Captain John M Cox, the CEO of Safety Operating Systems, said whatever took place occurred very quickly.
"We know the airplane is down. Beyond that, we don't know a whole lot," he said.
Airplane crashes typically occur during take-off and the climb away from an airport, or while coming in for a landing.
Only 9% of fatal accidents happen when a plane is at cruising altitude, according to a statistical summary of commercial jet airplane accidents done by Boeing.
Aviation expert David Learmount told Sky News the Boeing 777-222 had an "absolutely superb" safety record.
"Aviation safety now is quite extraordinarily good. It's far better than it was 20-30 years ago - I mean massively better," he said.
"That's why things like this are so surprising. They just should not happen any longer."
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