Abstract: | To plan and schedule the repair shops for recoverable parts at Deutsche Lufthansa AC, we designed a hierarchical model consisting of two levels. The top level calculates the optimal number of parts in the system to guarantee a certain service level while minimizing the capital tied up in parts. Given this provision, the lower level schedules the repair of parts so that the service level is actually maintained. Using queuing theory, the solution gives special attention to the different hierarchical dependencies. Lufthansa has implemented the model for its repair shops of electronic parts. Their experience with the model is discussed briefly. |