This very well might explain why it hasn't been found.
U.S. Investigators Suspect Missing Malaysia Airlines Plane Flew On for Hours - WSJ.com
By ANDY PASZTOR
Updated March 13, 2014 4:17 a.m. ET
U.S. investigators suspect that Malaysia Airlines Flight 370 stayed in the air for about 4 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 murky.
Aviation investigators and national security officials believe the plane flew for a total of 5 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 program
That raises a host of new questions and possibilities about what happened aboard the widebody 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.
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 intentionally turning off the jetliner's transponders to avoid radar detection, according to one person tracking the probe