Conflicting theories as to what exactly caused flight to mysteriously disappear
The disappearance of the Boeing 777 on March 8, 2014, still baffles the experts, who cannot find a trace of wreckage or come up with a definitive explanation for its sudden disappearance.
More tragically, its loss still haunts the lives of those whose friends and family were aboard the doomed plane.
Malaysia Airlines Flight MH370 left Kuala Lumpur for Beijing with 227 passengers and 12 crew on board. Piloted by Captain Zaharie Ahmad Shah, the plane was due to fly north-east from Kuala Lumpur across Malaysia.
Its usual path should have taken it across the Gulf of Thailand, then over Cambodia, Laos, Vietnam and mainland China, before landing just under six hours later at 6.30am. Instead, final contact with air traffic control occurred at 1.19am, when a co-pilot, believed to be Fariq Abdul Hamid, radioed: "Alright, good night."
Two minutes later, the plane failed to check in as scheduled with air traffic control in Ho Chi Minh City, Vietnam. No distress signal was received.
Radar showed that the plane made a sharp left turn, from north-east to almost due west.
According to a report released by the Malaysian Government last May, 17 minutes later, at 1.38am, Vietnamese air traffic control became concerned and asked other countries and nearby aircraft to attempt to make contact.
Some 37 minutes later, at 2.15am, MH370's position was picked up for the final time - by Malaysian military radar. The aircraft was heading north-west, across the Andaman Sea. Finally, after four hours of mounting panic and confusion, the alarm was raised at 5.30am and a search and rescue operation launched.
Initial searches focused on the South China Sea, south of Vietnam's Ca Mau peninsula. The loss of the aircraft was confirmed at a press conference at 11.14am.
What happened after plane contact was lost?
Theory A is that the jet continued on a northwards trajectory. At 2.15am, Malaysian military radar plotted MH370 at a point south of Phuket in the Strait of Malacca, west of its last known location.
Thai military radar logs also then confirmed that the plane turned west and then north over the Andaman Sea. A week later, it was revealed that satellites above the Indian Ocean reported seven contacts - known as 'handshakes' - during the night of March 8, with the last occurring at 8.19am. This makes it possible that the jet travelled along a flight corridor stretching north between Thailand, as far north as Kazakhstan.
Theory B is that it headed west. The plane's sharp turn left after contact was lost could mean that the plane was being flown to Diego Garcia, the tiny British-owned island in the Indian Ocean which is used as a military base by the US.
'Haveeru', a leading Maldives newspaper, reported that several islanders on Kudahuvadhoo in Dhaalu Atoll spotted a low-flying jet over their territory at about 6.15am the day the plane went missing. The residents claimed the plane was flying towards the Addu Atoll, the southern tip of the Maldives.
Theory C is that it turned south. Satellite 'handshakes' could indicate that the plane flew south between Indonesia and the southern Indian Ocean. Two objects spotted on satellite in the Southern Indian Ocean some 12 days later appeared to confirm this theory.
As a result, the search operation was focused on the Roaring Forties, one of the world's roughest stretches of oceans, 1,800km off the coast of Western Australia.
However, almost half of the targeted 120,000 sq km zone has yet to offer up any trace of the Boeing 777.
Why did it crash?
One theory is that the plane suffered a structural failure.
MH370's violent turn west after contact is lost could be explained by a sudden decompression in the cabin. Its violent left turn after contact was lost could have been the crew's failed attempt to reach the safety of the 13,000ft runway at Pulau Langkawi, an archipelago 30km off the mainland coast of northwestern Malaysia.
A second theory is that it was sabotaged.
According to a preliminary report by Australian air crash investigators, the Boeing 777 suffered a mysterious power outage during the early stages of its flight, which experts believed could have been part of an attempt to avoid radar detection.
The plane's satellite data unit made an unexpected "log-on" request - or 'handshake' - to a satellite less than 90 minutes into its flight.
This could have been caused by an interruption of electrical power on board the plane.
The theory was given credence by the belated discovery that two Iranian passengers on board MH370 were travelling on false passports.
However, further investigation revealed that Pouria Nour Mohammad Mehrdad (19) and Delavar Seyed Mohammadreza (29) were headed for Europe via Beijing, but had no apparent links to terrorist groups.(© Daily Telegraph, London)