Last month, an American Airlines passenger jet and an Army helicopter collided as the plane prepared to land at Washington D.C.’s Ronald Reagan National Airport.

Senator Ted Cruz, the chairman of the committee with oversight of transportation, said there was no compelling reason for the technology not to have been in use when the helicopter collided with a commercial jet over the Potomac River.

Air traffic controller audio TIME retrieved from LiveATC.net revealed what happened moments before the collision. The tower had cleared the plane for landing on Runway 33, but just seconds before the crash, an air traffic operator asked the helicopter—with radio call sign PAT 25—if the commercial jet—referred to as the CRJ—was in sight.

The NTSB chairwoman said the recording from the helicopter cockpit suggests the crew may have missed a key instruction just before the Jan. 29 collision.

National Transportation Safety Board Chairwoman Jennifer Homendy told reporters that the recording from the Black Hawk helicopter cockpit suggested an incomplete radio transmission may have left the crew without understanding how it should shift position just before the Jan.