Pilots have long worried about the congested and complex airspace around the airport near the heart of the capital, where flights must maneuver around military aircraft and restricted areas. It was no secret there had been previous close calls, but the numbers found by the NTSB were alarming.

Helicopters will be permanently restricted from flying near Washington, D.C.'s airport on the same route where a passenger jet and an Army helicopter collided in midair, killing 67 people, the Federal Aviation Administration said Friday.