BEIJING, March 9 (Xinhua) -- More than 40 hours have passed since the missing Malaysian plane carrying 239 people, including more than 150 Chinese, lost contact with air traffic controllers.
Yet the fate of the China-bound Malaysia Airlines plane remains unknown, prompting speculations and worries.
Listed below are the explanations from experts to some of the major mysteries surrounding the missing plane.
HOW THE PLANE SUDDENLY LOST ALL CONTACT?
Analysts gave three possibilities: 1. The plane might have wrongly flown into a cumulonimbus and lost control. 2. Some accidents happened to the pilots. 3. The air-to-ground communication was cut off because of malfunction.
The ground monitors the plane through three ways: the main one is radar surveillance, then voice communication and then the air-ground data link system based on satellite communication technology. Only when the three means are exhausted, can a plane be identified as losing contact.
The lack of a call "suggests something very sudden and very violent happened," William Waldock, who teaches accident investigation at Embry-Riddle Aeronautical University in Prescott, Ariz, was quoted by media as saying.
If there was a minor mechanical failure, or even something more serious like the shutdown of both of the plane's engines, the pilots likely would have had time to radio for help, he said.
Media reports say that the investigation may last for years.
The deadly air crash of Air France Flight 447 in 2009 was initially believed to be the result of lightning strike, but the investigation report three years later showed that it was the technical malfunction and human factor that caused the accident.
WHAT HAPPENED TO THE PLANE AT CRUISING ALTITUDE?
The jet's disappearance was especially mysterious because it apparently happened when the plane was at cruising altitude, not during the more dangerous phases of takeoff or landing.
Just nine percent of fatal accidents happen when a plane is at cruising altitude, according to a statistical summary of commercial jet accidents compiled by Boeing.
Experts speculate that the plane might have suddenly disintegrated in the air or dived vertically in high speed.
After the 9-11 terrorist attacks in 2001, airplanes around the world have all installed bulletproof doors for airline cockpits, which gave enough time for pilots to inform the ground if a plane was hijacked by terrorists, according to civil aviation pilots.
Moreover, it is impossible for the plane to vanish from the radar screen if the transponder remains active.
Whatever happened to the missing plane, experts think that a conclusion is still too early to tell.