American Airlines has received notice from the US FAA that the agency intends to issue a second fine against the carrier for maintenance violations.
The proposed $300,000 penalty follows a proposed fine of $787,500 by FAA against American on 12 March for three other maintenance violations.
FAA today alleges that on 2 February 2009 American mechanics deferred maintenance on a Boeing MD-80 under the aircraft's minimum equipment list (MEL), when they noted that the "pitot/stall heater light off" light on the aircraft's annunicator panel was inoperative.
MELs list components and systems that the aircraft can operate safely without in certain conditions.
FAA says the day after the deferred maintenance was noted, American's maintenance personnel determined the inoperative part was actually the captain's pitot probe heater.
Pitot probes are placed on aircraft surfaces to measure airspeed, and since ice can build up on the probes the devices are equipped with heaters.
The agency explains the aircraft's MEL allows for deferral of maintenance of the pitot probe's heater, but it restricts flights to daylight hours in visual meteorological conditions (VMC). Flights into known or forecast icing or visible moisture are prohibited.
"Because the mechanics logged the discrepancy as an inoperative panel light, the flight crew was unaware that the daytime, VMC restrictions applied to further flights," says FAA.
FAA explains American violated Federal Aviation Regulations by operating the aircraft on five passenger flights when the restrictions should have been applied.
The fines issued against American this month follow a $7.1 million penalty levied against the carrier in August 2008 for violating regulations governing maintenance and drug and alcohol testing.