There's an "intolerable risk to aviation safety" with helicopters and planes flying too close to one another near DCA.

The NTSB’s preliminary report on the Jan. 29 crash that killed 67 people said current helicopter routes allowed around the airport are an ‘intolerable risk to aviation safety.’

The National Transportation Safety Board said the separation between helicopters and jets in the area was insufficient and increased “chances of a midair collision.”