WASHINGTON, D.C. — The National Transportation Safety Board chairman called for immediate changes at Washington, D.C.'s Ronald Reagan Washington National Airport, saying the current helicopter routes around the airport "pose an intolerable risk to aviation safety."

Federal investigators looking for the cause of the January collision between a passenger jet and an Army helicopter near Washington, D.C., that killed 67 people are recommending a ban on some helicopter flights.

U.S. Transportation Secretary Sean Duffy on Tuesday said the agency will make permanent restrictions to prevent helicopters from flying near Washington Reagan National Airport when two lesser-used runways are operational,

An American Airlines passenger jet and an Army helicopter collided on Jan. 29 as the plane prepared to land at Washington, D.C.’s Ronald Reagan National Airport.

The NTSB says the current helicopter routes around the busy airport "pose an intolerable risk to aviation safety" in the wake of January's collision that killed 67 people.