The Federal Aviation Administration (FAA) said the air traffic control staffing was “not normal” during the Wednesday night plane collision between an American Airlines passenger plane and an Army Black Hawk training flight in a Thursday report.

“The position configuration was not normal for the time of day and volume of traffic,” the FAA wrote in their report, according to the Associated Press. 

The agency noted one air traffic controller was working in two different positions at the time of the crash, handling local and helicopter traffic.

Nick Daniels, president of the National Air Traffic Controllers Association, said it’s not “unusual or uncommon” for air traffic controllers to work more than one position at a time, according to CNN.

The National Air Traffic Controllers Association has called for changes in their shift rotations in recent months, requesting 10 hours off between work periods, 12 hours off before and after a midnight shift, and a limit on consecutive overtime assignments.

The FAA agreed to their terms and hired an additional 1,800 controllers, but near-miss crashes have persisted, according to the AP. 

Officials are waiting for a full investigation to determine the main cause of the crash.

“We will wait for the National Transportation Safety Board to complete its work and use that information to help guide decisions and changes to enhance and improve aviation safety,” Daniels shared in a statement to the outlet. 

Law enforcement immediately began recovery efforts from the Potomac River after the crash but does not expect to rescue any survivors.

The National Transportation Safety Board said flight data from the aircrafts’ black boxes have been recovered and will provide further information for their investigation, according to CNN.