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 key safety system was turned off on a U.S. Army helicopter that collided with an American Airlines regional jet last week near Washington 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),

The Army Black Hawk helicopter involved in the fatal midair collision in Washington, D.C., had a tracking system turned off, Sen. Ted Cruz said.

Sen. Ted Cruz said a key safety system was turned off aboard the Black Hawk helicopter that collided with a plane in Washington, D.C. His comments followed a closed-door meeting with the NTSB.

The black hawk helicopter involved in the deadly collision with an American Airlines jet over Washington, D.C. has a crucial safety system turned off at the time.