The U.S. Department of Transportation’s Federal Aviation Administration (FAA) proposes a $474,000 civil penalty against Frontier Airlines, Inc. of Denver, Colo., for allegedly operating aircraft that lacked required medical supplies on hundreds of flights.

The FAA alleges that in June and July 2017, Frontier personnel installed on 11 aircraft emergency medical kits that lacked either injectable epinephrine, or atropine, or both.

On July 10, 2017, Frontier was made aware that the company was operating aircraft with detective emergency medical kits, the FAA alleges. The company on July 11 applied for an exemption allowing it to continue flying with those medical kits. The FAA granted the exemption on Sept. 16, 2017.

However, the FAA alleges Frontier operated the 11 aircraft on 787 revenue flights between July 11 and July 27, 2017–after it had become aware of the problem and before the FAA issued the exemption.

Frontier has asked to meet with the FAA to discuss the case.