Comparison of FMEA and field-experience for a turbofan engine with application to case based reasoning

The failure modes and effects analysis for the TFE731, a popular turbofan engine, was compared to field experience with the same engine type recorded over several years of in-service troubleshooting activities, while engines were installed on the aircraft. This effort was undertaken to better understand the relationship between failure modes anticipated at the equipment design stage and the failure modes encountered in the field. Out of 727 failure modes encountered in the field, 142 (20%) matched FJVLEA anticipated failure modes, of which there were 610. The majority of failure modes encountered in-service involved engine controls, electronics, and accessory systems. Analysis of the datasets provides direction for selecting which FMEA records could be transformed into diagnostic cases for improved efficiency in developing a seed diagnostic application using case-based reasoning. FMEA transformation to cases is discussed, with a comparison of the design and maintenance terminology and focus. Generalization of the FMEA transformation process to any complex equipment is discussed.