A review by US regulators into maintenance oversight at American Airlines indicates that FAA did not recognise weakness in the carrier's maintenance and engineering programmes that were associated with a January 2008 emergency landing of a Boeing 757 after the cockpit filled with smoke.

The Inspector General branch of the US Department of Transportation (DOT) recently published a report that summarises a review of FAA oversight of American's maintenance after IG received a complaint that outlined 10 maintenance related allegations that could have contributed to a deterioration in the carrier's reliability.

One of those allegation cited by the complainant was American not adhering to a service bulletin issued by Boeing that could have prevented cockpit windshield failures.

Adherence to service bulletins is not required, but the IG points out those documents "often highlight safety issues that lead to the issuance of airworthiness directives".

The service bulletin that alerted 757 operators to a problem with a windshield heating component was published in 2006. Left uncorrected, the component could overheat and cause smoke to enter the cockpit and either crack or shatter the windshield.

In the January 2008 incident, an American 757 had to divert to West Palm Beach on a flight from San Juan to Philadelphia after smoke from the first officer's windshield heater filled the cockpit, forcing pilots to don oxygen masks and smoke goggles.

IG in its investigation discovered the American engineer responsible for drafting the engineering change order that is required to issue work cards to mechanics left the company, and the order was never released,

"The CMO [certificate management office overseeing American] incorrectly concluded, however, that American cancelled the order because it opposed the replacement windshields called for in the service bulletin," says IG.

American says it engineers in 2006 verbally requested an inspection of the windshield heat components as the aircraft underwent maintenance, but the request was not documented, resulting in IG being unable to verify if inspections were conducted.

American says its engineering analysis demonstrated failures were due to design efficiencies not addressed by the Boeing service bulletins. "Recognising the shortcoming, American instead opted to replace all of the suspect window assemblies with new windows from a different manufacturer. American is already more than 60% complete through with this replacement campaign."

The January 2008 incident was followed by the grounding of the carrier's MD-80 fleet during the second quarter of that year over issues surrounding AD compliance related to the bundling of wires in wheel wells of the aircraft. The grounding resulted in the cancellation of roughly 3,000 flights.

In 2009 additional MD-80 issues surfaced at the carrier related to improper fasteners used in bulkheads on the aircraft.

Other conclusions of IG's analysis include the confirmation of allegations that maintenance deferrals at American increased by 32% from 298 on average per day to 394 from 2004 through the first five months of 2008, and American's failure to follow certain procedures to comply with maintenance inspections.

American explains the IG's report highlighted processes that required additional review and improvement, and the carrier working with FAA has responded by adding internal auditors to its staff.

Emphasising the IG reports examines events that occurred two years ago the carrier states: "In this timeframe, American has conducted numerous self-audits and successfully passed several government-led maintenance and safety audits."

Source: Air Transport Intelligence news