Scheduled and SHM structural airframe maintenance applications using a new probabilistic model

This paper focuses on aircraft structure maintenance. A general mathematical framework based on a probabilistic analytical model was developed to provide the average number of fuselage panels to be replaced after any number of cycles and over the aircraft lifetime under fatigue damage failure [1]. This paper proposes a study to explore structure maintenance strategies using this analytical model. Both scheduled maintenance and condition-based maintenance using SHM are considered for different aircrafts with different lifetimes and timetable inspections. In each case, the aircraft lifecycle cost is evaluated in terms of average number of panels changed. A similar study based on Monte Carlo method is presented in [2]. We studied the results given by this approach considering same maintenance strategies as mentioned above. Because the simulation conditions are not exactly the same, the results obtained using the PAM are a little bit different than the ones obtained by Monte Carlo simulations; indeed, it shows an adequacy. Compared to Monte Carlo method, the analytical model is of a great interest regarding the accuracy because the recurrence formula leads to an exact expression of the average number of fuselage panels to be replaced.