Reliability with imperfect diagnostics

A reliability estimation method for systems that continually accumulate faults because of imperfect diagnostics is developed and an application for redundant digital avionics is presented. The present method assumes that if a fault does not appear in a short period of time, it will remain hidden until a majority of components are faulty and the system fails. A certain proportion of a component's faults are detected in a short period of time, and a description of their detection is included in the reliability model. A Markov model of failure during flight for a nonreconfigurable five-plex is presented for a sequence of one-hour flights followed by maintenance.