Reliability Approach Applied on Fatigue Safety Factors for Fleet Monitoring

French armament procurement agency (DGA) is currently implementing a reliability approach in order to check aircraft safety level. The goal of the method is to carry out a quantitative study about the structural failure based on random phenomenon. Physical randomness is considered in the aviation regulation with the use of scatter factors. Dealing with safe-life substantiated aircraft, DGA, in charge of airworthiness, allows the reduction from 5 to 3 of the fatigue scatter factor for the monitored fleets with a safety level at least preserved. Two aspects are analyzed with the reliability method: The first application evaluates the safety level induced by different monitoring systems. The second one quantifies the safety level of aircraft without monitoring system compared with monitored ones in order to evaluate the reduce scatter factor.