- Published on Monday, 10 March 2014 11:20
Almost 48 hours since the plane carrying 239 people vanished - the investigation poses more questions than answers
In the early hours of Saturday morning, a jetliner carrying 227 passengers and 12 crew took off from the Malaysian capital Kuala Lumpur for Beijing in China.
It climbed into the night's sky, heading over the South China Sea.
But 41 minutes later, air traffic controllers lost contact with the pilot, 53-year-old Zaharie Ahmad Shah, and the Boeing 777-200ER simply vanished into thin air.
Since then, an international investigation involving 11 countries has failed to find any concrete sign of the plane or come up with an explanation for what happened.
Almost 48 hours later, the plane would definitely have run out of fuel, and has not turned up at any other airport.
With every passing hour, more and more facts emerge, but each seeming to make the mystery ever deeper.
Here, we pose ten key questions about the fate of flight MH370 which remain unanswered:
Why was there no distress signal?
Air traffic controllers in Subang, outside Kuala Lumpur, did not receive a distress signal from flight MH370.
Neither the pilot nor his co-pilot made any attempt to indicate there was a problem.
The jet could be tracked one second, and was gone the next.
A leading aviation safety expert said he found it "extraordinary" that there is no record of a distress call.
The plane would have been cruising at about 35,000 feet when it lost contact, giving the pilots "plenty of time" to report any technical problems, Flight Global's operations and safety editor David Learmount said.
"Something happened and the pilots did not tell anyone. Why? It's a good question," he said.
"It's extraordinary the pilots failed to call because they had plenty of time to. Unless there was a bomb on board but there has been no evidence of that."
How did passengers get on a plane using stolen passports?
Interpol confirmed "at least" two passports recorded as lost or stolen in its database were used by passengers on board the missing flight and said the agency is checking for other suspect passports.
Interpol said no checks of its database had been made by any country on an Austrian and an Italian passport between the time that they were stolen and the departure of the flight.
The Italian who was believed to have been on board, 37-year-old Luigi Maraldi has since been pictured alive and well in Thailand.
The Austrian, 30-year-old Christian Kozel has also been confirmed as alive and well and back home in Austria.
Both are believed to have had passports stolen in Thailand in the past year.
"Whilst it is too soon to speculate about any connection between these stolen passports and the missing plane, it is clearly of great concern that any passenger was able to board an international flight using a stolen passport listed in Interpol’s databases," Interpol Secretary General Ronald Noble said in a statement.
The police agency said it was in contact with its offices in the countries involved to try to establish the true identities of the passengers who boarded the flight with the stolen documents.
It said it is also checking all other passports on the flight "which may have been reported stolen".
Noble expressed frustration that few of Interpol’s 190 member countries "systematically" search the database to determine whether documents being used to board a plane are registered as lost or stolen.
"This is a situation we had hoped never to see. For years Interpol has asked why should countries wait for a tragedy to put prudent security measures in place at borders and boarding gates," he said.
Are there any links to terrorism?
The lack of distress signal or evidence of mechanical fault, plus the revelation of stolen passports, has led some to speculate that the flight was the target of a terrorist attack.
There were 14 nationalities on board, the vast majority Chinese nationals.
A number of ethnic minorities have waged terror attacks against the Chinese state.
The largely Muslim Uyghur ethnic group, concentrated in the north-western province of Xinjiang, are more closely attached to the cultures of Central Asia and have fought for independence from China on several occasions.
Just last week the group was blamed for a violent attack at a Chinese train station.
Tibet has resisted control from China for centuries.
However, so far no group has claimed responsibility for an attack on the flight.
Why have search teams not found any debris?
It is almost 48 hours since flight MH370 went missing.
Dozens of vessels and aircraft from 11 countries have been scouring the South China Sea for signs of the jet without success.
Possible sightings of debris have been made, but none have been confirmed.
Why are missing passenger's mobile phones still ringing?
At least one relative of a Chinese passenger on board the missing flight has successfully been able to ring his mobile phone - but nobody answers.
Eerie video footage emerged of the family of the missing man ringing his phone live on state television.
The call connected, but no one picked up.
A group of passengers have reportedly handed a petition to Malaysia Airlines to reveal "the real truth" about what happened to the flight.
Why did it take so long for Malaysia Airlines to reveal the plane was missing?
Air traffic controllers lost contact with flight MH370 at 2.40am.
But for hours, relatives waiting in Beijing simply thought the flight had merely been 'delayed'.
Display boards in the airport gave no indication of the disaster which had unfolded.
Furious family members say they found out that the plane had gone missing from news stories, rather than Malaysian Airlines.
The company eventually issued a statement at 9.05am on Saturday, March 8 admitting: "We deeply regret that we have lost all contacts with flight MH370 which departed Kuala Lumpur at 12.41 am earlier this morning bound for Beijing."
Was the delay simply down to incompetence on the part of panicking airline bosses? Or was the delay covering something more sinister?
Did the plane try and turn back?
Radar signals indicate the jet may have tried to turn back towards Kuala Lumpur, investigators say.
Military officers said the were looking at the possibility that flight MH370 had tried to turn back from its scheduled path before vanishing.
"What we have done is actually look into the recording on the radar that we have and we realised there is a possibility the aircraft did make a turnback," Rodzali Daud, the Royal Malaysian Air Force chief, told reporters at a news conference.
If true, was this an attempt to land after a mid-air disaster? Or because of some element of foul play on board the aircraft?
Why did another pilot hear mumbling and interference when he tried to contact flight MH370?
A pilot who was flying in the vicinity of flight MH370 said he heard mumbling and interference when he tried to contact the missing plane.
The pilot, who asked to remain anonymous, told the New Straits Times that his plane, which was bound for Narita, Japan, was able to make contact using an emergency frequency.
"We managed to establish contact with MH370 just after 1.30am and asked them if they have transferred into Vietnamese airspace," he said.
"The voice on the other side could have been either Captain Zaharie (Ahmad Shah, 53,) or Fariq (Abdul Hamid, 27), but I was sure it was the copilot
“There were a lot of interference ... static ... but I heard mumbling from the other end.
“That was the last time we heard from them, as we lost the connection,” he told the New Sunday Times.
Are the oil slicks found in the ocean of any significance?
A Vietnamese search plane saw two possible oil slicks in the area the flight went missing.
Aerial photographs of the streaks, said to be around 12 miles long, have been released.
But vessels who were sent to the area failed to find any further sign of the plane and it cannot be confirmed they are linked to flight MH370.
Yet they remain the strongest piece of evidence of crash so far.
Will we EVER know what happened for sure?
The sudden disappearance of the jetliner represents one of the rarest kinds of aviation disaster, and the mystery is compounded by uncertainty about which country's jurisdiction the plane came down in.
Take-off and, in particular, final approach and landing are the most inherently hazardous parts of a flight, and the periods when most accidents occur.
But it has been more than 48 hours since the plane went missing and Malaysia Airlines said it was "fearing the worst".
"Aircraft do not crash while en route like this," said Paul Hayes, Director of Safety at Flightglobal Ascend, a British-based aviation consultancy. "It is an extremely unusual event."
Only one other recent disaster was similar: the loss of Air France Flight 447, which crashed in the Atlantic Ocean in 2009 en route from Rio de Janeiro to Paris.
Investigations were unable to conclusively come up with a reason for the crash of the Airbus A330 until the plane's black boxes - its flight and voice data recorders - were recovered from the bottom of the ocean two years later.
The incident is likely to rekindle a debate about whether black box flight recorders should be replaced with satellite-based systems capable of sending back telemetry in real time. Such systems exist, but have so far been ruled out on the basis of cost and logistics.