A number of anomalies in qualification test firings of solid rocket motors and failures in space in the mid 1980s gave an impetus for a number of detailed investigations into a method of non-destructively assuring the integrity of carbon-carbon and carbon-phenolic solid rocket motor nozzle exit cones. Boeing has been concerned with improving technology in this area and has led the industry in development and applications of both non-destructive inspection and evaluation approaches. To supplement traditional approaches, Boeing has developed acceptance criteria based on a performance model and also procedures to use these criteria. These use data from multiple-modality NDE of exit cones together with prior thermomechanical property correlations to determine the performance capability of individual exit cones, on a case by case basis.