During the hearings, the NTSB was told that the Army helicopter never heard the command from the air traffic controller to "pass behind the CRJ" as the transmission was stepped on. It was also revealed that the plane's pilots were not warned by the controller that there was a helicopter nearby or cleared to fly near the helicopter.

Last week, the NTSB held three days of hearings looking into what led up to the fatal crash between a plane and a helicopter in January.

At their closest points, helicopters and planes routinely flew within 75 feet near the airport, according to the NTSB.