The Tucson (Ariz.) Police Department has grounded three helicopters and a fixed-wing aircraft after an audit by the Airborne Law Enforcement Association (ALEA) discovered that pilots and mechanics had been fighting over safety issues that contributed to a hostile work environment, according to a report from the Mohave Valley Daily News.

Tucson Police Chief Roberto Villaseñor took the aircraft out of service on Dec. 23 after the association said the airborne unit was only 58% in compliance with ALEA standards, placing it at high operational risk.

The department has 30 days from the grounding to get the unit operational again, and according to Assistant Police Chief Mark Timpf, they are running ahead of schedule.