The Federal Aviation Administration says helicopters will be permanently banned from flying near Washington, D.C.’s airport on the route where an airliner and an Army helicopter collided in midair. The move announced Friday comes just days after federal investigators recommended a ban on some helicopter flights after pointing out a string of earlier near misses.

The closure comes after crash investigators said there was a history of safety risks near the busy airport that had gone unaddressed.

The closure of the helicopter route near the airport makes permanent the restrictions put in place after Jan. 29 midair collision.