An air traffic controller did not inform the crew of a commercial flight about an approaching Army helicopter, resulting in a collision in Washington, D.C., this past January and claiming 67 lives, as reported by a representative from the Federal Aviation Administration on Thursday.

This first admission by the FAA regarding a potential mistake by Ronald Reagan National Airport’s control tower came amidst ongoing National Transportation Safety Board hearings investigating the circumstances that led to the tragic midair accident.

Testimonies during the hearing highlighted the significant volume of takeoffs and landings at the airport, coupled with intense helicopter activity, pushing air traffic controllers to their safety limits, according to The Washington Post.

On the night of the incident, practices included relying on helicopter crews’ judgment to steer clear of other traffic and using runway 33. This shorter runway necessitates jets approaching from the south to deviate from the typical flight path, extending their eastward trajectory, the outlet reported.

Controller staffing at the airport has been concerning since the incident, disclosed NTSB investigator Brian Soper. Latest FAA figures reveal that although there are 26 controllers designated to the tower, only 19 are operable.

“Every person we spoke with cited staffing as a significant concern,” Soper said.