An American Airlines regional jet collided with a U.S. Army Black Hawk helicopter on Jan. 29. Both aircraft plunged into the Potomac River near Reagan Airport.

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.

The NTSB says when the Jan. 29 collision between a passenger plane and helicopter occurred, the air traffic control tower had five persons on duty.