“We’ve determined that the existing separation distances between helicopter traffic operating on Route 4 and aircraft landing on Runway 33 are insufficient and pose an intolerable risk to aviation safety by increasing the chances of a mid-air collision at DCA,” NTSB Chair Jennifer Homendy said during a news conference.

Share on Facebook Share on Twitter Future accidents are a concern for the National Transportation Safety Board after the deadly mid-air collision between an American Airlines passenger jet and an Army helicopter in January.

Current airport flight safety practices create an "intolerable safety risk" that could be eliminated by changing allowed separation distances between helicopters and airplanes, federal officials say.