Did plane land on sea, then sink?

A new theory is suggesting that the pilot of AirAsia flight QZ8501 may have managed to make an emergency water landing, only for the plane to be overcome by high seas.

Aviation veterans suggested that the absence of transmissions normally emitted when a plane crashes or is submerged points towards this possibility, AFP reported.

"The emergency locator transmitter would work on impact, be that land, sea or the sides of a mountain.

"My analysis is it didn't work because there was no major impact during landing," said Mr Dudi Sudibyo, a senior editor of aviation magazine Angkasa.

"The pilot (could have) managed to land it on the sea's surface," he added.

Mr Chappy Hakim, a former air force commander, told AFP: "The conclusions I have come to so far are that the plane did not blow up mid-air and it did not suffer an impact when it hit a surface, because if it did so, then the bodies would not be intact."

So far, nine bodies have been recovered, say reports.

The fuselage (an aircraft's main body section that holds crew and passengers) is also thought to be largely intact after aerial searchers saw a "shadow" on the seabed, where operations are now being focused.

An emergency exit door and an inflatable slide were among the first items recovered by the search team, suggesting that the first passengers to leave the plane may have started the evacuation process once it landed on water.

Former transport minister Jusman Syafii Djamal was convinced that the discovery of the floating exit door meant someone had opened it.

Passengers may have been waiting for a flight attendant to inflate a life raft when a high wave hit the nose and sank the plane, he said.