The investigation into a January midair collision that killed 67 people near Washington, D.C., revealed an alarming number of recent close calls just outside the nation’s capital.

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.

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.’