In the three years before the deadly collision between an Army helicopter and an American Airlines flight near Reagan National Airport, at least two other pilots reported near-misses with helicopters while landing at the airport,

The report, reviewed by The New York Times, said that one controller was communicating with both helicopters and planes. Those jobs are typically assigned to two people, not one.

The crash disrupted flights at Reagan National Airport. Several dozen emergency crews could be seen at the scene of the crash, apparently just south of Reagan National Airport’s upper departure area,