The Carroll-Hung method for component reliability mapping in aircraft maintenance

摘要

Mean time between unscheduled removal (MTBUR) measurement is a baseline technique for condition monitoring (CM) in aircraft reliability programmes. Many airlines, component suppliers and airframe manufacturers apply MTBUR analysis because of its simplicity and industry-wide acceptance for contractual, performance and technical evaluation purposes. Owing to its aggregated nature, MTBUR alone has little to offer for showing the significant changes within a repairable component population. This paper introduces the Carroll-Hung (CH) method, an innovative approach for bridging the industrial practice of CM alerts and the process of identifying candidates for reliability improvement. Through systematic mapping of modulated time-to-failure patterns onto finger-print charts, trained engineers are able to scrutinize life characteristics and then detect inherent issues by making reference to a CH pattern guidebook. Applications at two airlines have proved the method to be simple and effective because the CH algorithm and its unique failure pattern examination technique involve aircraft system knowledge and logistics factors in developing component improvement plans. Possible refinement of the CH methodology using a non-parametric approach and pattern recognition is planned for future research.