a law enforcement official told CNN that the plane's programmed change in direction was entered at least 12 minutes before the plane's verbal sign-off.
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A U.S. official told CNN that somebody programmed Flight 370 to fly off course. But it's unclear if that happened during the flight or before takeoff.
"We don't know when specifically it was entered," said Mary Schiavo, a CNN aviation analyst and former inspector general for the U.S. Department of Transportation.
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Reports, not yet confirmed by authorities, have suggested that Flight 370 followed navigational waypoints after it turned off its original route less than an hour into its journey on March 8.
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Programming waypoints into the flight management system of a Boeing 777-200 is "a task that would have been beyond the abilities of anyone but a professional pilot," said Robert Goyer, the editor in chief of Flying magazine and a commercial jet-rated pilot.
Once the pilots are in the aircraft, "anything is possible," said Ahmad Jauhari.