U.S. investigators1 suspect that Malaysia Airlines 3786.KU -2.04% Flight 370 stayed in the air for about four hours past the time it reached its last confirmed location, according to two people familiar with the details, raising the possibility that the plane could have flown on for hundreds of additional miles under conditions that remain murky2.
据两位知情人士透露，美国调查人员怀疑马航370航班离开最后被定位的位置后，仍在空中飞行约4个小时。而这意味着飞机在失联后可能又继续飞行了几百英里，虽然后来飞行时的具体情况目前尚未可知。
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. BA -0.99% 777's engines as part of a routine maintenance and monitoring program.
That raises a host of new questions and possibilities about what happened aboard the widebody jet carrying 239 people, which vanished from
civilian3 air-traffic control
radar4 over the weekend, about one hour into a flight to Beijing from Kuala Lumpur.
Six days after the mysterious
disappearance5 prompted a massive international air and water search that so far hasn't produced any results, the
investigation6 appears to be broadening in scope.
U.S. counterterrorism officials are pursuing the possibility that a pilot or someone else on board the plane may have diverted it toward an undisclosed location after
intentionally7 turning off the jetliner's transponders to avoid radar detection, according to one person tracking the probe.
The investigation
remains8 fluid, and it isn't clear whether investigators have evidence indicating possible terrorism or
espionage9. So far, U.S. national security officials have said that nothing specifically points toward terrorism, though they haven't ruled it out.
But the huge
uncertainty10 about where the plane was headed, and why it
apparently11 continued flying so long without working transponders, has raised theories among investigators that the aircraft may have been
commandeered（征用，霸占） for a reason that appears unclear to U.S. authorities. Some of those theories have been laid out to national security officials and senior personnel from various U.S. agencies, according to one person familiar with the matter.
At one briefing, according to this person, officials were told investigators are
actively12 pursuing the notion that the plane was diverted "with the intention of using it later for another purpose."
As of Wednesday it remained unclear whether the plane reached an alternate destination or if it ultimately crashed, potentially hundreds of miles from where an international search effort has been focused.
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