The
9/11 Commission estimated that the flight was hijacked between 08:51 and 08:54, shortly after
American Airlines Flight 11 struck the North Tower of the World Trade Center and not too long after
United Airlines Flight 175 had been hijacked. The last normal radio communications from the aircraft to
air traffic control occurred at 08:50:51.
[30] Unlike the other three flights, there were no reports of anyone being stabbed or a bomb threat and the pilots were possibly not immediately killed but herded to the back of the plane with the rest of the passengers. At 08:54, as the plane flew in the vicinity over
Pike County,
Ohio, it began to deviate from its normal assigned flight path and turned south.
[31] Two minutes later, at 08:56, the plane's transponder was switched off.
[23] The hijackers set the flight's
autopilot on a course heading east towards
Washington, D.C.[32]
The FAA was aware at this point there was an emergency on board the airplane. By this time, Flight 11 had already crashed into the North Tower of the World Trade Center and Flight 175 was known to have been hijacked and was within minutes of striking the South Tower. After learning of this second hijacking involving an American Airlines aircraft and the hijacking involving United Airlines, American Airlines' executive vice president Gerard Arpey ordered a nationwide ground stop for the airline.
[23] The Indianapolis Air Traffic Control Center, as well as American Airlines dispatchers, made several failed attempts to contact the aircraft. At the time the airplane was hijacked, it was flying over
an area of limited radar coverage.
[33] With air controllers unable to contact the flight by radio, an Indianapolis official declared that it had possibly crashed at 09:09.
[33]
[33] Phillips, Don (November 3, 2001). "Pentagon Crash Highlights a Radar Gap; Limited System in One Area Made Flight 77 Invisible to Controllers for Half-Hour".
The Washington Post.