A few theories on what happened to MH370
THE following cover some of the scenarios being mulled over by the regional authorities, investigators and industry experts.
Is mechanical or structural failure likely?
Sudden, accidental structural failures leading to explosions or a sudden loss of cabin pressure are considered extremely unlikely in today's passenger aircraft.
This is especially so with the Boeing 777-200 model, which has one of the best safety records of any jet.
"From a crack, there can be a whole structure breakdown that allows for no response. But, in the last two to three decades, there have been next to nil such incidents," said Mr Ravi Madavaram, an aviation analyst with Frost & Sullivan.
How likely is human error in this case?
The MH370 case may draw comparisons with the crash in 2009 of an Air France aircraft into the Atlantic Ocean, which killed more than 200 people.
An investigation said speed sensors failed, causing the Airbus jet to stall and lose altitude. But it also said pilots failed to react correctly, losing control of the jet.
Indonesia-based aviation analyst Gerry Soejatman said that, despite all the safety features on modern aircraft, well-trained pilots taking proper action in an emergency is essential.
"If the crew is not on the ball, they quickly lose control of the situation," he said.
Was it an attempted hijacking or terror attack?
This spectre has loomed after the authorities said at least two passengers had boarded with stolen passports. Malaysian officials also said yesterday radar data indicated the pilot may have inexplicably tried to turn back to Kuala Lumpur.
Analysts said the absence of any distress signal raises eyebrows, as it could indicate an event so sudden that the crew could not respond.
The terror theory's credibility is hurt by the fact that - so far - no claim of responsibility has surfaced.
Experts said stolen passports do not necessarily equate to terrorism. Large numbers of illegal workers, as well as criminal syndicates, are known to move between Malaysia and neighbouring countries, such as Thailand. The two suspects' passports were reportedly stolen in Thailand.
Could violent turbulence or bad weather have brought down the plane?
This possibility is being widely discounted, as all indications are that the weather was fine in the area where contact with MH370 was lost.
Could it have run out of fuel?
Malaysia Airlines has said the plane was fuelled for at least eight hours of flight. The Kuala Lumpur-Beijing route lasts six hours.
Mr Ravi said: "If there was a fuel loss, the pilot would have enough time to send a distress signal, and to turn around and glide back to land."