Malaysia Airlines Flight MH370: What we know 2 years later

One little piece of a wing has been found, along with perhaps a part of a tail section. Beyond that, the fate ofMalaysia Airlines Flight MH370 remains an aviation mystery, two years after the Boeing 777 went missingon its way to Beijing.

Many questions remainafter the plane's disappearance in the early hours of March 8, 2014.

With all the satellite surveillance and tracking technology available today, how could a jetlinersimply vanish? And why hasn't itbeen found, even after a wing flap was discovered washed up on a remote island in the Indian Ocean?

• Flight MH370 debris could reach Mozambique, officials say
• Analysis suggests plane located within official search area
• France confirms part found on Runion Island is from missing plane

Here's a look at what is known about Malaysia Airlines Flight MH370, as well as some theories about what might have happened.

What we know

Departure time

The planetook off from Kuala Lumpur at 12:41 a.m.local time on March 8, 2014, carrying 239 people. The original destination was Beijing, with arrival scheduledfor nearly six hours later, at 6:30 a.m. local time.

Last ACARS message

Malaysian authorities say that at1:07 a.m., the plane sent its last message via the Aircraft Communications Addressing and Reporting System (ACARS), an automated system that relays performance data about each flight (including turbulence, fuel usage and any maintenance concerns) to the airline.

Sign-off from the cockpit

Malaysian authorities reported having audio of either the pilot, Capt. Zaharie Ahmad Shah, or his first officer, Fariq Abdul Hamid, saying, "All right, good night" in a transmission to air traffic control.

The Malaysian government later changed its account of the final voice transmission, saying the last words received by controllers at Kuala Lumpur's international airport at 1:19 a.m. local time on March 8 were "Good night Malaysian three-seven-zero."

Transponder disabled

After 40 minutes of flight time, at about1:21 a.m., the plane's transponder stopped transmitting and ground control lost contact with the aircraft.

Last confirmed position

At2:14 a.m., just over one and a half hours after the plane departed KualaLumpur, Malaysian military radar identified the plane in the northern part of the Strait of Malacca.

Last satellite signal

ACARS continued to transmit "pings" to satellites for four to five hours, a senior U.S. official told CNN.

The last signal was picked up by a satellite at8:11 a.m., which suggests MH370 had deviated from its northward course to Beijing and was somewhere in a geographical radius spanning from Kazakhstan to the Indian Ocean west of Australia.

Search area

Search efforts have been adjusted several times, buthave focusedon a 120,000-square-kilometre expanse ofremote waters west of Australia. The plane is believed to have crashed in that area after flying on autopilot forhours before running out of fuel. In December 2015, the Australian-led search efforts wererefocused on the southern reaches of the search zone, based on a new analysis of the flight's last hours.

Debris discoveries

In September 2015,French investigators formally identified a washed-up piece of airplane debris foundthree months earlier on a remote island in the Indian Ocean as part of Flight 370. The wing part, called a flaperon,wasfound on Runion Island and later identified using maintenance records and aserial number.

Debris that washed up in Mozambique in late February 2016 was tentatively identified as being from a Boeing 777. Officials say debris from Flight 370 could reach Mozambique, a coastal country in southeastern Africaabout 6,000 kilometres from the area where the plane is believed to have crashed.

4 theories about flight MH370

The mysterious disappearance of MH370 sparked speculation from experts and amateurs alike. Hereare some of the theories.

Passengers and crew suffocated

On June 26, 2014,the Australian Transport Safety Board released a 55-page report that concluded the passengers and crew suffocated on-board, and that the plane eventually fell into the ocean.

The report saidinvestigators came to this conclusionby comparing the conditions on the flight with previous disasters, but offered no evidence from within the aircraft.

The investigatorsnoted, among other things,the lack of communications and the steady flight path.

"Given these observations, the final stages of the unresponsive crew/hypoxia event type appeared to best fit the available evidence for the final period of MH370's flight when it was heading in a generally southerly direction," the ATSB report said.

Hijacking

When flightMH370 went missing, some observers suggested it might have been hijacked by extremists with a political agenda.

After satellite data showed that MH370 had made a sharp westward deviation from its intended destination, some took this as proof of a mid-air takeover.

No extremist group has claimed responsibility for such an act.

Sabotage

Flight MH370's seemingly deliberate change of course also spurred theories that it may be a case of sabotage.

On March 14, 2014, a senior Malaysian police official said, "What we can say is we are looking at sabotage, with hijacking still on the cards."

Mechanical failure

ChrisGoodfellow, a Canadian pilot with 20 years' experience, posited a more straightforward theorythat wasreprinted in Wired magazine.

Goodfellowwrotethat "there most likely was an electrical fire" that forced thepilot to "make an immediate turn to the closest, safest airport."

Based on the satellite data about where FlightMH370was heading after it turned off its course to Beijing,Goodfellowdetermined that the pilot'sintended destination was a 4,000-metre airstrip onPulauLangkawi, an island in northern Malaysia.