System Level RUL Estimation for Multiple-Component Systems

Aircraft are highly valuable assets and large budgets are spent in predictive maintenance programs in order to maximize fleet availability. The application of PHM (Prognostics and Health Monitoring) technologies can be a powerful decision support tool to help maintenance planners. The estimated RUL (Remaining Useful Life) for each monitored component, obtained from a PHM system, can be used to plan in advance for the repair of components before a failure occurs. However, when system architecture is not taken into account, the use of PHM information may lead the operator to replace a component that would not immediately affect the availability of the system under consideration. In this paper, a methodology that combines fault tree information and individual components RUL estimations into a system level RUL (S-RUL) estimation is applied in a real life case study. The results showed that the methodology could have been successfully used in order to anticipate the failure of an aircraft ECS (Environmental Control System) and prevent an AOG (Aircraft on Ground) event from happening.