The disappearance of flight MH370 has become the biggest mystery in modern aviation history. Leaving aside the wilder conspiracy possibilities, the leading theories about what happened to the plane and its passengers are:
1. Pieces of the plane, or most of the plane itself, are at the bottom of the ocean
Searchers have been unable to find pieces of the plane floating on the water's surface, despite a multination task force searching a widened search area. That may be because the plane now lies at the bottom of the South China Sea, over which its last communication took place. The search began at part of the sea that is relatively shallow, but failure to find any debris there leads to the possibility it may lie in a deeper location. What's more, as time passes, ocean currents will spread the debris field, if there is one, farther and farther apart.
2. The plane crashed – but into the jungle – not the ocean
The inability to find anything on the ocean has led some experts to wonder whether the plane crashed into the dense Malaysian jungle – or exploded in mid-air with debris falling into that jungle – with the jungle's tall trees obscuring the crash site. (The "black box" transmits signals for six or seven kilometres. Malaysia's Taman Negara jungle is more than 4,000-square-kilometres in size.) Under this case, the plane turned back on its course, and flew out of contact, for an unknown reason. (The last communication did show the plane turning slightly.)
Of course, these two theories – and the fact the plane suddenly stopped communicating – prompt the question: Why did the plane crash?
- style="margin-bottom:1em">A major mid-air explosion
Some sort of explosion – such as a bomb – depressurized the cabin instantly, knocking out communications, and killing everyone or at least rendering them all unconscious. Debris then fell to Earth. A high-altitude break up would spread debris over a wide area, unlike if the plane crashed relatively intact and broke apart upon hitting the surface. Again, ocean currents would cause any debris field to spread further apart with each passing hour.
- The transponder was purposefully switched off
The suddenness with which communication was lost is one of the most mystifying aspects for experts. This has led some to wonder, that if there was no “catastrophic event” such as a bomb, then perhaps the pilot, either by himself or under duress, intentionally switched off communications, for some unknown purpose.
3. The plane flew for four hours after radar contact was lost
The Wall Street Journal reported a new theory on Thursday morning. It claimed that even after manual communication with the plan was lost, automated and routine data transmissions from the plane's engines to their manufacturer Rolls Royce continued to be received for several hours. If true, that could mean the plane travelled 3,000 kilometres from its last known point. Unfortunately, these transmissions contain only data concerning the engines' performance – not location. In either case, Malaysian authorities have dismissed the possibility these data transmissions actually occurred. Later Thursday, the WSJ clarified its story to say that the signals were actually onboard systems sending "pings" -- brief transmissions -- which were received by satellites, not engines sending status updates to Rolls Royce.
Expanding this theory leads investigators to consider the possibility that the plane did not crash, but landed safely at an undisclosed location "with the intention of using it later for another purpose," according to an investigator quoted in the WSJ report.
Sources: Wall Street Journal, AP, Encyclopedia Britannica