Investigators trying to determine what caused last week’s deadly midair collision between a US military Black Hawk helicopter and an American Airlines plane near Washington, DC, briefed lawmakers Thursday on what they’ve learned after combing through data from both aircraft and air traffic control.

After American Airlines Flight 5342 and a U.S. Army helicopter collided mid-air, officials shared insight into the respective pilots’ communication with air traffic control.

Moment US army helicopter wreckage pulled from river after DC plane crashSource: National Transportation Safety Board

Radar evidence proves that the Black Hawk helicopter was not flying low enough during collision with American Airlines Flight 5342.

A feared blunder made by the black hawk helicopter moments before colliding with an American Airlines passenger jet has been confirmed.