Flight instruments probably led the Black Hawk crew to believe the helicopter was lower than it actually was before the collision with a commercial airplane on Jan. 29.

The National Transportation Safety Board will hold three days of hearings on the fatal midair collision between a passenger jet and an Army helicopter.

In May, the FAA barred the Army from helicopter flights around the Pentagon after a May 1 close call that forced two civilian planes to abort landings. The FAA this week said the