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.

The National Transportation Safety Board is seeking more flight restrictions on helicopters around Ronald Reagan Washington National Airport. The NTSB's "urgent" recommendations come more than a month after a Jan.

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,