The story of what happened to Malaysia Airlines flight MH370, which went missing on March 8 and has yet to be found, has confounded aviation experts and kept news watchers hanging on every development in the last 100 days.
With all of the satellite surveillance and tracking technology available today, how could a plane simply vanish? Many observers have likened it to the plot of a spy novel.
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On June 26, Australian officials released a report saying the passengers and crew most likely died from suffocation and and coasted into the ocean on autopilot. But the Australian report contained no new evidence from within the vessel.
Hard evidence about what actually happened during MH370’s aborted journey is still relatively scant. In the absence of definitive answers, many theories about the fate of the jetliner and the 239 people aboard have emerged in the media and on social networking sites – some more outlandish than others.
Here’s a look at what is known about Malaysia Airlines flight MH370, as well as some of the theories about what might have happened.
What we know
The plane, a Boeing 777, took off from Kuala Lumpur at 12:41 a.m. local time on March 8, carrying 239 people. The original destination was Beijing.
Last ACARS message
Malaysian authorities say that at 1:07 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 report 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.
It has not been conclusively determined whether this sign-off was transmitted before or after the plane’s transponder was disabled, although a senior Malaysian official told the New York Times on March 16 that the transponder was disabled first.
After 40 minutes of flight time, at about 1:21 a.m., the plane’s transponder stopped transmitting and ground control lost contact with the aircraft.
Last confirmed position
At 2:14 a.m., just over one and a half hours after the plane departed Kuala Lumpur, Malaysian military radar identified the plane in the northern part of the Strait of Malacca. This is MH370’s last known confirmed position.
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 at 8:11 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.
4 theories about flight MH370
The mysterious disappearance of MH370 has sparked speculation from experts and amateurs alike. Here's a look at some of the theories circulating in the news.
Passengers and crew suffocated
On June 26, 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 said investigators come to this conclusion by comparing the conditions on the flight with previous disasters, but offered no novel evidence from within the aircraft.
The investigators noted, 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.
When flight MH370 first went missing, some observers suggested that 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 thus far claimed responsibility for such an act.
Flight MH370’s seemingly deliberate change of course has also spurred theories that it may be a case of sabotage.
On March 14, a senior Malaysian police official said, "What we can say is we are looking at sabotage, with hijacking still on the cards.”
Chris Goodfellow, a Canadian pilot with 20 years’ experience, has posited a rather more straightforward theory that was reprinted in Wired magazine.
Goodfellow writes that “there most likely was an electrical fire” that forced the pilot to “make an immediate turn to the closest, safest airport.”
Based on the satellite data about where flight MH370 was heading after it turned off its course to Beijing, Goodfellow determined that the pilot's intended destination was a 13,000-foot airstrip on Pulau Langkawi, an island in northern Malaysia.
Online and in social media, much more far-fetched and outlandish ideas have been circulating.
One commenter on China’s popular social media site Sina Weibo suggested that MH370 could have been struck by a meteor. "It would have been a more powerful impact than a missile,” said the user, “laxnic,” and “would have split the plane into tiny pieces."
A writer for conspiracy theory site ForbiddenKnowledgeTV.com has interpreted unusual data on the flight-mapping site Flightradar24.com on the date of the disappearance as a sign a UFO might have intercepted the Malaysia Airlines plane.
The "Bermuda Triangle" effect
Some people on social media networks have suggested that flight MH370 had the misfortune of travelling into a region in southeast Asia similar to the Bermuda Triangle, an area in the Caribbean where a number of aircraft and ships have gone missing under mysterious circumstances.
One enterprising tweeter placed the “new” Bermuda Triangle in an area between northern Malaysia to the west, Indonesia’s Riau Islands to the east and Vietnam’s Con Dao island to the north.
With files from Thomson Reuters