Mexican budget carrier Volaris is facing a federal fine of up to $735,000 for violating safety inspection rules.
The Federal Aviation Administration (FAA) has proposed the fine after the airline continually operated an Airbus A319 despite being informed necessary safety inspections had not been carried out in March 2013.
The FAA alleges Volaris flew the plane on 121 occasions before carrying out the required safety checks.
The FAA said certain tasks were not completed during the ‘heavy maintenance inspection’ which included checking the condition of an evacuation emergency slide.
"The traveling public relies on airlines to ensure that airplanes are properly maintained, which includes paying close attention to all maintenance requirements," said FAA Administrator Michael Huerta.
The airline was given 30 days to respond to the FAA charge.
