from mirror uk:
The US Government insists the plane exploded on impact, yet a one-ton section of the engine was found over a mile away and other light debris was found scattered over eight miles away.
THE MOBILE CALL
Passenger Edward Felt made an emergency call from the plane. He spoke of an explosion and seeing some white smoke. The superviser who took the call has been gagged by the FBI.
UA93 was identified as a hijack at 9.16am. At 9.35am three F-16s were ordered to "protect the White House at all costs" when it turned towards the capital. At 10.06am it crashed at Shanksville, less than 10mins flying time from Washington.
THE BLACK BOXES
Sources claim the last thing heard on the cockpit voice recorder is the sound of wind - suggesting the plane had been holed.
THE SONIC BOOM
The FBI insists there was no military plane in the area but at 9.22am a sonic boom - caused by a supersonic jet - was picked up by an earthquake monitor in southern Pennsylvania, 60 miles away from Shanksville.