Applied Repairable-item Inventory Modeling in the Aviation Industry

In the aviation industry, reliable spare parts supply is essential for continuous aircraft operation. Spare parts of high value are repaired and returned to stock after removal from the aircraft, forming a closed-loop supply chain. Current planning methods of maintenance, repair, -and overhaul providers (MRO providers) as well as research findings published to date do not cover the requirements of the commercial aviation industry. This paper presents a spare part inventory planning method that calculates cost-optimal inventory levels for warehouses in a two- echelon supply chain for spare parts supply in the aviation industry and takes into account various input and output planning parameter, such as budget and inventory level limitations. The development and introduction of the planning method is accompanied by a change management process. For validation of the calculated inventory levels a simulation model is used and sensitivity analyses are conducted. Using the discrete- event simulation model, effects of the demand level at local warehouses and its influence on the central warehouse are investigated.