Optimal replacement of safety-critical aircraft parts with utilization uncertainties

This paper aims to propose a practical approach to solving a maintenance optimization problem with uncertain system utilizations. This problem arises when we want to determine the optimal replacement time for turbine wheels, a safety-critical part in aircraft engines, by considering both the utilization uncertainties and the fact that a fleet of engines have been operating in the field for several years. It is important to conduct the trade-off analysis in order to balance the safety requirement and the maintenance cost. The proposed research will investigate the maintenance issue in the following steps: First of all, we will develop a quantitative model to estimate the uncertainties in aircraft engine utilizations. The model will be further verified based on the field data such as component and system lifetimes, repair and replacement costs. Secondly, we will propose an optimization-based framework to minimize the maintenance cost by incorporating system utilization uncertainties. Finally, a Monte Carlo simulation program is developed to solve the optimization problem. Both analytical and simulation results will be compared in terms of the computational complexity and the estimation accuracy.