Verification of an airframe fatigue life monitoring system using ex-service structure

In this paper the verification of the Royal Australian Air Force's (RAAF) F/A-18 Hornet Airframe Service Life Monitoring system is summarised. The availability of a significant number of RAAF ex-service centre fuselage sections with known usage facilitated this effort. Using an enhanced teardown procedure, in-service crack growth was identified at a significant number of locations. By comparing measured in-service growth with full scale fatigue test-demonstrated growth, and fitting failure distributions to the in-service data, the effectiveness of the monitoring system in maintaining a specific probability of failure was assessed.