Evaluation of Prescriptive Maintenance Strategies for a Tire Pressure Indication System (TPIS) assuming Imperfect Maintenance

Abstract

Digital technologies for condition monitoring enable failure predictions of aircraft systems and will have an enormous impact on aircraft maintenance in the future. Current research studies evaluate the potential of these technologies within prescriptive maintenance strategies. These strategies combine failure predictions of a system with given operational environmental conditions to identify the optimal time for maintenance. However, current prescriptive maintenance models neglect the impact of imperfect maintenance, which affects system reliability, system availability and its associated costs. The goal of this thesis is to investigate how this impact of imperfect maintenance affects prescriptive maintenance strategies including the tire pressure indication system. In addition, an aviation maintenance stakeholder model for a prescriptive simulation model of the tire pressure indication system is presented, which will allow for more precise strategy development in future implementations. This aviation maintenance stakeholder model includes the stakeholders aircraft maintenance, airline, mechanics, logistics service providers, and component maintenance. The imperfect maintenance model considers the impact of human factors in addition to technological influences. The effects of fatigue, procedure design, certifications, training, experience, age, and environmental conditions are included into the model to determine the degree of imperfection of a performed task. Imperfect maintenance considers discretely performed maintenance tasks and calculates a new system state after the execution of an imperfect repair. For the development of prescriptive maintenance strategies for the tire pressure indication system, the obtained results of a sensitivity analysis are used. In this context, the parameters of the imperfect maintenance model are analyzed with regard to the objective maintenance cost. These strategies are subsequently compared to the defined state-of-the-art tire maintenance process. In comparison, the application of the tire pressure indication system in addition to human factor optimization indicates the highest cost savings potential of 67 percent.