Here are some possible scenarios that could have happen to the missing MH370:
1. THE PLANE COULD HAVE CAUGHT FIRE MID-AIR
A fire probably broke out on board MH370 and the pilot was trying to save the plane by making a sharp left turn to land on the Malaysian island of Langkawi, said an experienced Canadian pilot.
But the flight crew might have been overcome by smoke, and the aircraft continued flying on autopilot until it ran out of fuel, said Mr Chris Goodfellow. Another possible scenario: The fire could have destroyed the control surfaces and the plane crashed.
The loss of transponders and communications made sense in a fire, he wrote in an article, adding it was likely electrical. The pilot's first response would be to shut down and restart the circuits.
Another possible cause of fire was overheating of one of the landing gear tyres, which blew on takeoff and started burning slowly.
"Fire in an aircraft demands one thing: Get the machine on the ground as soon as possible," he said, adding that Langkawi is closer than Kuala Lumpur.
What experts say: Some say this explanation makes sense.
But others quoted reports which said the left turn was achieved using a computer system on the plane. That would involve typing seven or eight keystrokes into the computer. If the course was changed during a major emergency, it would more likely be done using manual control.
Moreover, the electronic "ping" detected by the Inmarsat satellite at 8.11am on March 8, the day it went missing, narrowed its location at that moment to one of two arcs - one in Central Asia and the other in the southern Indian Ocean. Neither area is in the direction of Langkawi.
2. THE PLANE COULD HAVE "STALKED" ANOTHER AIRCRAFT TO AVOID RADAR DETECTION
Some believe the plane could have hidden in the shadow of another plane. With its transponders and lights switched off, it could trail another aircraft undetected in the night sky. To a ground radar controller, the planes would appear as one or two "blips", depending on how close they were.
Aviation blogger Keith Ledgerwood believes MH370 could have trailed the Barcelona-bound Singapore Airlines (SIA) Flight SQ68, which left Changi Airport at about 1.05am. When contacted, an SIA spokesman said: "All queries related to MH370 have to be directed to the investigating authorities."
What experts say: It would be difficult for a large aircraft like the Boeing 700-200ER to closely shadow a plane at night without radar help. Military radar, which has higher resolution, would be able to detect two objects unless they were less than 1,000m apart.
3. THE PLANE COULD HAVE USED "TERRAIN-MASKING" TECHNIQUE TO AVOID DETECTION
MH370 could have dropped to an altitude of 1,500m or lower to avoid civilian radar, said the New Straits Times, quoting officials.
It is also possible that it hugged the terrain in mountainous areas to avoid radar detection. The technique, called terrain-masking, is used by military pilots to fly to their targets stealthily.
What experts say: Aviation expert Jason Middleton of New South Wales University told the British Guardian newspaper that how to avoid radar is well known. "Radar goes in a straight line. If you are in the shadow of a mountain or even the curve of the Earth, you can't be seen."
4. THE PLANE WAS HIJACKED BY A CREW MEMBER OR PASSENGER
Pilot Zaharie Ahmad Shah, 53, co-pilot Fariq Abdul Hamid, 27, and passengers with aviation expertise were investigated.
The police looked into whether the pilot had practised landings on his home flight simulator at airports located in the two vast tracts of territory where the search is focused.
Reports claimed that police found five airports on the simulator: Diego Garcia in the Indian Ocean, Male (Maldives), two in India and one in Sri Lanka.
What experts say: Police have not found anything suspicious, even though Malaysia revealed yesterday that data logs had been recently deleted from the home flight simulator. It is unlikely the plane had been hijacked by a third party as no statement or demand has been made.
5. THE PLANE COULD HAVE CRASHED OR EXPLODED
Some believe the plane might have crashed into the ocean or exploded in mid-air, which is why no debris has been found.
What experts say: The Austria-based Comprehensive Nuclear-Test-Ban Treaty Organisation, which has extremely sensitive sensors throughout the world, says it did not detect any explosion or crash - either on land or at sea.
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