American Airlines flight 77 was a morning flight on a Boeing 757 from Washington Dulles to Los Angeles (IAD-LAX). On September 11, 2001, the plane was hijacked and crashed into the western side of the Pentagon at 9:43 AM EDT, starting a violent fire. The plane was carrying 58 passengers and 6 crew. There were no survivors.
The section of the Pentagon hit was reported to consist mainly of new, unoccupied offices. Barbara K. Olson had called her husband, Solicitor General Theodore Olson at the Justice Department at 9:25 from the plane to tell him about the hijacking and to report that the passengers and pilots were held in the back of the plane.
See September 11, 2001 Terrorist Attack/Plane_casualties for the flight manifest.