The
probable cause has been determined.
The NTSB board said it was likely the use of a helicopter route that passed right next to Reagan as well as a faulty attempt by the Army helicopter to fly around Flight 5342.
That "visual separation" led to the midair collision, because the Black Hawk is believed to have been looking at the wrong plane.
Other causal factors were the lack of regular review of the problematic helicopter routes around Reagan, a busy airport; and the "loss of situation awareness and degraded performance," under heavy strain, by the air traffic controllers at the time, as well as no processes for them to counter risk, leading them to not issue more clear and more urgent traffic warnings to the chopper and plane.
Contributing factors included an "unsustainable arrival rate" at the airport, which increased the workload on the air traffic control tower, as well as failures by the Army and FAA to track or implement needed safety reforms.
Another issue was the lack of better collision avoidance and alert systems on both crafts.
