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Audit Reports


Air Carriers' Outsourcing of Aircraft Maintenance

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On September 30, 2008, we issued our audit of air carriers’ outsourcing of aircraft maintenance. We conducted this audit at the request of the House Committee on Transportation and Infrastructure. Air carriers are increasingly outsourcing maintenance to repair stations to reduce operating costs. When an air carrier uses a repair station that is certificated by the Federal Aviation Administration (FAA) to repair its aircraft or parts, the repair station’s organization becomes an extension of the air carrier’s maintenance organization. Our audit objectives were to (1) identify the type and quantity of maintenance performed by external repair stations and (2) determine whether FAA is effectively monitoring air carriers’ oversight of external repair stations’ work and verifying that safety requirements are met. We found that while FAA has begun moving its safety oversight toward a risk–based system, it still relies too heavily on air carriers’ oversight procedures, which are not always sufficient. Specifically, we determined that FAA did not (1) have an adequate system for determining how much and where the most critical maintenance occurs, (2) have a specific policy governing when certificate management inspectors should visit repair stations performing substantial maintenance, (3) require inspectors to validate that repair stations have corrected deficiencies identified in air carrier audits, and (4) have adequate controls to ensure that inspectors document inspection findings in the national database and review related findings by other inspectors. As a result, FAA could not effectively target its inspection resources to those repair stations providing the highest volume of repairs, which caused deficiencies at repair stations to go undetected or reoccur and prevented inspectors from obtaining sufficient data to perform comprehensive risk assessments. We recommended that FAA develop and implement an effective system to determine how much and where critical maintenance is performed. In addition, FAA must ensure that inspectors conduct initial and follow–up inspections at substantial maintenance providers, perform detailed reviews of air carrier and repair station audits and corrective actions, document inspection findings in the national database, and review related findings by other inspectors. In addition, since many air carriers do not differentiate between in–house and outsourced maintenance, FAA must ensure air carriers provide repair stations with clearer guidance on how to perform maintenance and inspections at repair stations. FAA is working to address this issue through a rulemaking change but needs to pursue interim actions to establish agreements between air carriers and repair stations on maintenance procedures.