“…Due to military budgetary constraints and civilian industry requirements, all of these older aircraft either have encountered ageing problems, such as fatigue cracking, stress corrosion cracking (SCC) or corrosion [1,2]. Fatigue cracks often initiate from impact damage occurring during pre-flight and taxiing operations, dropped tools during maintenance, runaway debris, hail or bird strike [3,4]. Such damaged structures are frequently required to remain in service for extended periods, despite the occurrence of damage.…”