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.

A 3-D model created by The Times visualizes the helicopter pilots’ field of view minutes before a fatal crash with a jet in Washington.

The Army helicopter that collided with a passenger plane above the Potomac River boasted an experienced crew doing “an unforgiving job.” Friends and relatives are still baffled and mourning their loss.

The U.S. Army helicopter that collided with an passenger jet near Washington, D.C., had an advanced surveillance system turned off.

Technology that would have allowed air traffic controllers to better track the movement of an Army helicopter was turned off at the time of the crash, Sen. Ted Cruz, R-Texas, said in an interview Thursday.

A key safety system was turned off on the U.S. Army helicopter that collided with an American Airlines regional jet last week near Washington's Reagan Airport, killing 67. Senate Commerce Committee chair Ted Cruz told reporters the Black Hawk helicopter had turned off its automatic dependent surveillance-broadcast (ADS-B),