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

Sixty-four people aboard a commercial airliner died Wednesday after it collided with a military helicopter midair near Reagan Washington National Airport. Both the American Eagle jet and Army Black Hawk are in the Potomac River.

Data from air traffic control radar showed the military chopper was flying at 300 feet on the air traffic control display at the time of the fiery crash, according to the NTSB.