Nearly three decades before last week’s deadly mid-air collision between an American Airlines flight and a military helicopter, a deadly plane crash in Los Angeles changed aviation safety standards forever.

The Army helicopter that collided with a passenger jet last week in Washington had its tracking technology turned off at the time of the crash, U.S. Senator Ted Cruz told the New York Times. The technology allows air traffic controllers to better track the movement of an aircraft.

Army Black Hawk helicopter that collided with an American Eagle flight over the Potomac River​ late last month was flying with a safety system turned off, Sen. Ted Cruz told reporters after a briefing from the FAA and NTSB.

More information has emerged in the investigation into the mid-air collision over the Potomac River between an American Airlines jet and an Army Black Hawk helicopter,