The reliability theory for fatigue lives of one-crack, two-stage models with hijacking has been extended to allow for arbitrary inspection intervals with possible arbitrary renewals. The life distribution is similar with a modified initiation density and the associated moment generating function is formally identical. It is possible to identify an unsteady Markov chain formed by the combined fatigue and inspection process. Two FORTRAN programs have been developed from this formulation, one of which allows for random crack rates and run-time setting of inspections
