Robust Aircraft Maintenance Routing with Heterogenous Aircraft Maintenance Tasks

Robust aircraft maintenance routing problems (RAMRPs) have been extensively studied due to their significance on flight schedule reliability. In the current practice, the traditional huge A-check program is divided into multiple Heterogeneous small maintenance packages (with different maintenance durations and risk levels) and performed differently during the ground time between two connected flights. As the available maintenance time becomes relatively shorter, maintenance becomes a new source of disruption. Thus, the assignment of maintenance packages-to-ground times becomes more critical. Accordingly, this paper proposes a robust strategy to alleviate the disruption due to maintenance risk. The strategy is to provide each package the appropriate amount of buffer time based on the fuzzy risk assessment. Correspondingly, a robustness measure is developed to construct the RAMRP model. As its impact can be better illustrated in large scale problems, we adopt matheuristic approach. We examine 500 disruption scenarios, the results show that the proposed strategy can greatly reduce flight delays (i.e., an 82.7% reduction in the number of delayed flights) while maintaining an acceptable decrease in aircraft utilization (i.e., a 32.42% increase in average unused flying times) compared to those obtained from the traditional model. Additionally, the proposed model is further investigated from the perspectives of aircraft utilization constraints and the risk-averse attitude of airlines. Our study validates its cost-effectiveness for delay risks reduction and highlights the significance of being properly risk-averse in decision making.