The US aviation regulator said Friday it has ordered stricter safety around Washington's Ronald Reagan airport after a devastating collision between a passenger jet and a military helicopter. The Federal Aviation Administration also closed part of a corridor near Ronald Reagan National Airport that the military helicopter was using when it collided with the Bombardier CRJ-700 jet.

The investigation into a January midair collision that killed 67 people near Washington, D.C., revealed an alarming number of recent close calls just outside the nation’s capital.

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

The Federal Aviation Administration said Friday it is imposing permanently restrictions on non-essential helicopter operations around Washington Reagan National Airport and eliminating helicopter and passenger jet mixed traffic.

The US Federal Aviation Administration detailed a series of restrictions on helicopter traffic near Ronald Reagan Washington National Airport following a deadly midair collision in January.