Decision Analysis Model for Optimal Aircraft Engine Maintenance Policies Using Discrete Event Simulation

With stringent standards for materials, manufacturing, operation, and quality control, jet engines in use on commercial aircraft are very reliable. It is not uncommon for engines to operate for thousands of hours before being scheduled for inspection, service or repair. However, due to required maintenance and unexpected failures aircraft must be periodically grounded and their engines attended to. The tasks of maintenance and repair without optimal planning can be costly and result in prolonged maintenance times, reduced availability and possible flight delays.

This chapter presents the development of Discrete Event Simulation (DES) models that utilize aircraft flying, grounding and engines service times, as well as Time-On-Wing (TOW) data which represents the current accumulated flying time for each engine since its last service, and Remaining-Time-to-Fly (RTTF) to aid maintenance policy decision making. The objective is to determine the optimum number of engines on an aircraft for maintenance that leads to greater use of the estimated remaining useful life of the engines and shorter downtime for the aircraft. To achieve this, first, a number of small models are built and simulations performed to gain an insight into the problem. A final model is then developed that is based on the integration of these small models. It is shown that a simulation model of this type can enable the decision maker to readily examine different policies and from the analysis of the simulation output arrive at an optimum policy.