On Jan. 29, an American Airlines passenger jet and an Army helicopter collided as the plane prepared to land at Washington D.C.’s Ronald Reagan National Airport. Both plunged into the Potomac River, killing all 67 people aboard.

Investigators revealed that the U.S. Army Black Hawk helicopter that collided with American Airlines Flight 5342 was flying about 100 feet higher than it should have been, and also stated the helicopter crew was warned about the incoming jet two times.