Abstract
This article summarizes 2 related research projects sponsored by the National Aeronautics and Space Administration (NASA) Aviation Safety and Security Program. As NASA, the Federal Aviation Administration, and the airline industry have sought to understand causal factors of accidents and incidents, one emerging concern has been aircraft maintenance and subsequent inspection. Risk assessment methodologies are powerful tools for use in understanding the vulnerabilities of complex systems. This article discusses how these techniques are being used to predict the probability of inspectors detecting structural cracks in aluminum aircraft and dents in composite aircraft.