Analysis of electronic pulses picked up from a missing Malaysian airliner shows it could have run out of fuel and crashed into the Indian Ocean after it flew hundreds of miles off course, a source familiar with official U.S. assessments said on Friday.
The source, who is familiar with data the U.S. government is receiving from the investigation into the disappearance of the Malaysia Airlines plane, said the other, less likely possibility was that it flew on towards India.
The data obtained from pulses the plane sent to satellites had been interpreted to provide two different analyses because it was ambiguous, said the source, who declined to be identified because the investigation was continuing.
But it offers the first real clues as to the fate of Flight MH370, which officials increasingly believe was deliberately diverted off its scheduled course from Kuala Lumpur to Beijing. The Boeing 777-200ER was carrying 239 people.
Two sources familiar with the probe earlier said Malaysian military radar data showed a plane that investigators suspect was Flight MH370 following a commonly used navigational route toward the Middle East and Europe when it was last spotted by radar early on March 8, northwest of Malaysia.
The electronic pulses were believed to have been transmitted for several hours after the plane flew out of radar range, said the source familiar with the data.
The most likely possibility is that after travelling northwest, the airliner did a sharp turn to the south, into the Indian Ocean where officials think, based on the available data, it flew until it ran out of fuel and crashed into the sea, added the source.
The other interpretation from the pulses is that Flight MH370 continued to fly to the northwest and headed over Indian territory, said the source.
The plane had enough fuel for its scheduled flight that would have lasted just under six hours from Kuala Lumpur to Beijing and some for reserve.
At the point it was reported to have first diverted from its intended flight path, when it was off Malaysia's east coast, the plane would have had just under five hours of fuel left.
Around 45 minutes later, when the radar plot believed to be the aircraft was last spotted off Malaysia's northwest coast, it would have had enough fuel to fly for another four hours or so - enough to take it another 2,200 miles assuming a cruising speed and altitude of 35,000 feet.
Because of the fragmentary nature of the data, U.S. officials don't know for sure which analysis is correct, although they believe the turn to the south is more likely, the source said.
The source added that it was believed unlikely the plane flew for any length of time over India because that country has strong air defence and radar coverage and that should have allowed authorities there to see the plane and intercept it.
A U.S. government official, who requested anonymity as they were not authorized to speak publicly on the matter, explained that the satellite data was patchy because it was never intended to be a primary location system.
The official described the signals as a "handshake" - a brief interaction between plane and satellite.
In normal circumstances, this handshake would precede the sharing of more data, but this did not happen because the plane's transponders had been apparently switched off.
No location data was transmitted, the official said, merely a calculation telling the satellite in which direction to tilt its equipment to search for the plane.
Malaysian Transport Minister Hishammuddin Hussein said on Friday he could not confirm the last heading of the plane or if investigators were focusing on sabotage.
There has been no trace of the plane nor any sign of wreckage as the navies and military aircraft of more than a dozen countries scour the seas on both sides of peninsular Malaysia.