American investigators suspect that Malaysia Airlines flight MH370 stayed in the air for about four hours past the time it reached its last confirmed location, the Wall Street Journal reported today.
The business paper said this raised the possibility that the Boeing 777-200ER jet could have flown on for hundreds of additional kilometres under conditions that remain murky.
Aviation investigators and national security officials believe the plane flew for a total of five hours based on data automatically downloaded and sent to the ground from the Boeing Co 777's engines as part of a routine maintenance and monitoring programme, the paper said.
That raised a host of new questions and possibilities about what happened aboard the wide-body jet carrying 239 people, which vanished from civilian air-traffic control radar over the weekend, about one hour into a flight to Beijing from Kuala Lumpur.
Six days after the mysterious disappearance prompted a massive international air and water search that so far hasn't produced any results, the investigation appears to be broadening in scope.
United States counter-terrorism officials are pursuing the possibility that a pilot or someone else onboard the plane may have diverted it towards an undisclosed location after intentionally turning off the jetliner's transponders to avoid radar detection, according to one person tracking the probe.
The investigation remains fluid and it was not clear whether investigators have evidence indicating possible terrorism or espionage.
So far, American national security officials have said that nothing specifically points towards terrorism, though they have not ruled it out.
But the huge uncertainty about where the plane was headed, and why it apparently continued flying so long without working transponders, has raised theories among investigators that the aircraft may have been commandeered for a reason that appears unclear to US authorities, said the WSJ.
Some of those theories have been laid out to national security officials and senior personnel from various American agencies, according to one person familiar with the matter.
At one briefing, according to this person, officials were told investigators were actively pursuing the notion that the plane was diverted "with the intention of using it later for another purpose".
As of yesterday, it remained unclear whether the plane reached an alternate destination or if it ultimately crashed, potentially hundreds of kilometres from where an international search effort has been focused.
In those scenarios, neither mechanical problems, pilot mistakes nor some other type of catastrophic incident caused the 250-tonne plane to vanish mysteriously from radar.
The latest revelations come as local media reported that Malaysian police visited the home of at least one of the two pilots.
Boeing officials and a Malaysia Airlines official declined to comment.
The engines' onboard monitoring system is provided by their manufacturer, Rolls-Royce PLC, and it periodically sends bursts of data about engine health, operations and aircraft movements to facilities on the ground.
Rolls-Royce couldn't be reached for comment.
As part of its maintenance agreements, Malaysia Airlines transmits its engine data live to Rolls-Royce for analysis. The system compiles data from inside the 777's two Trent 800 engines and transmits snapshots of performance, as well as the altitude and speed of the jet.
Those snippets are compiled and transmitted in 30-minute increments, said one person familiar with the system.
According to Rolls-Royce's website, the data was processed automatically "so that subtle changes in condition from one flight to another can be detected".
The engine data is being analysed to help determine the flight path of the plane after the transponders stopped working.
The jet was originally headed for China, and its last verified position was halfway across the Gulf of Thailand.
A total flight time of five hours after departing Kuala Lumpur means the Boeing 777 could have continued for an additional distance of about 2,200 nautical miles, reaching points as far as the Indian Ocean, the border of Pakistan or even the Arabian Sea, based on the jet's cruising speed.
Earlier yesterday, frustrations over the protracted search for the missing plane mounted as both China and Vietnam vented their anger over what they viewed as poor coordination of the effort.
Government conflicts and national arguments over crises are hardly unique to the flight 370 situation, but some air-safety experts said they couldn't recall another recent instance of governments publicly feuding over search procedures during the early phase of an international investigation.
Authorities radically expanded the size of the search zone yesterday, which already was proving a challenge to cover effectively, but the mission hadn't turned up much by the end of the fifth day.
WSJ has confirmed that the pilot had the ability to turn off manually the transponder on flight MH370.
A mid-air catastrophe could have destroyed it. – March 13, 2014.