A regional jet carrying 64 people collided with an Army Black Hawk helicopter. Reagan National Airport grounded all flights.

A jet with 60 passengers and four crew members collided with an Army helicopter while approaching Ronald Reagan National Airport near Washington, D.C., sending the two aircraft plummeting into the Potomac River and killing everyone on board.

Through maps, videos, photos and radio transmissions, CNN is piecing together what occurred during the deadly, midair collision.

A midair collision between an Army helicopter and an American Airlines flight killed all 67 people aboard the two aircraft, officials said Thursday, as they scrutinized the actions of the military pilot and reported that control tower staffing was “not normal” at the time of the country's worst aviation disaster in a generation.