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."

WASHINGTON (AP) — 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 recommended a ban on some helicopter flights Tuesday to improve safety, saying the current setup “poses an intolerable risk.”

The National Transportation Safety Board on Tuesday made an urgent safety recommendation to prevent helicopters from flying near Washington Reagan National Airport when two lesser-used runways are operational,