Abstract: By comparing time and money consumption of LRU (line-replaceable unit) and non-LRU parts in aircraft maintenance, a method to optimize the LRU list for airlines is proposed. FTA (fault tree analysis) is used to filter the faulty parts and sort troubleshooting sequences. Then, combining the 3D model data or detailed structure information of components, disassembly path with troubleshooting progress of faulty parts can be calculated. MODAPTS (modular arrangement of predetermined time standard) is used to estimate the time cost in maintenance task progress and calculate the parking loss during faulty part maintenance considering the operating status of airlines. For aircraft in service, the parking loss is compared with the cost of replacement unit to determine whether the strategy of replacing the LRU component is better for cost cutting; for aircraft type designers, the parking loss could be the reference for them to propose designing request to OEM(original equipment manufacture).

Key words: line-replaceable unit (LRU), parking loss, fault tree analysis (FTA), disassembly path, modular arrangement of predetermined time standard (MODAPTS)