The Army goggles would have made it difficult to see the plane's colored lights, which might have helped the Black Hawk determine the plane's direction. The goggles also limited the pilots' peripheral vision as they flew near Ronald Reagan Washington National Airport.

The hearings in Washington will involve NTSB board members, investigators and witnesses. Panels will focus on military helicopter routes in the Washington area, collision avoidance technology and training for air traffic controllers at Ronald Reagan National Airport, among other subjects.

The National Transportation Safety Board said on Wednesday that testing showed faulty altitude data in U.S. Army helicopters like the one that collided with an American Airlines plane in Washington, D.