The contribution of maintenance to aviation risk: A statistical analysis
Abstract
Safety is paramount in the airline industry. A significant amount of research has been done on reducing mechanical failures and aircrew mistakes. Recently, more focus has been placed on the contribution of maintenance to airline safety. This study attempts to quantify the impact of maintenance on passenger airline safety by analyzing several different sources of data, including NTSB accident data, FAA & ASRS incident data, Service Difficulty Reports (SDRs), SAIBs (Special Airworthiness Information Bulletins) and ADs (Airworthiness Directives). Maintenance was found to be related to 7% of all aviation accidents and 16% of all aviation related fatalities since 1962. Maintenance-related accidents were also determined to be twice as likely to result in a fatality compared to accidents overall, indicating that maintenance accidents are, in general, more severe. Although maintenance-related accidents are more severe, the probability of maintenance causing an accident has decreased over the years. The decreasing trend in the accident risk associated with maintenance agrees with the overall trend in aviation. The risk associated with maintenance can present itself not only through the occurrence of accidents but through incidents as well. Maintenance was explicitly linked to 5% of all incidents recorded by the FAA between 2004 and 2008. Maintenance personnel were also responsible for submitting 7% of all incident reports received by the ASRS between 1999 and 2008. However, the lack of detailed investigations into component failures reduces the value of these figures. The prevalence of maintenance issues in enforcement activities is substantial. 36% of all penalties imposed on air carriers or maintenance facilities (AC&MF) were maintenance-related. The financial consequences of inadequate maintenance were also found to be significant with fines reaching $7.4M. In recent years, however, the degree of enforcement has decreased slightly, possibly because of an increase in leniency as a result of the economic hardships the aviation industry has endured since the turn of the millennium. An analysis of the relationships between the various categories of risk revealed some issues with the risk management system. For example, the data suggests that the FAA acts more reactively than proactively with respect to the issuance of airworthiness directives. Further, the large variance in both the severity and level of investigation of FAA incidents was deemed to be one of the limiting factors that needs to be addressed in order to continue to improve the level of safety associated with maintenance.
Degree
M.S.E.
Advisors
Marais, Purdue University.
Subject Area
Aerospace engineering
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