Despite terrorist bombs and structural failures, human error on the flight deck continues to account for the majority of aircraft accidents. The Royal Air Force (RAF) Institute of Aviation Medicine (IAM) has investigated the psychology of such error since the early 1970s, and to this end has used two principal techniques. The first has involved assisting in the official inquiries into both RAF and civil flying accidents, and the second has involved setting up a reporting system that permits any commercial pilot to report his own everyday errors, in complete confidence, to the RAF IAM. The latter system possesses the clear benefit of gathering error data untainted by considerations of culpability, and sometimes permits system rectification before the occurrence of accidents. This paper examines selected examples of errors associated with the design of equipment and with the social psychology of crews, and suggests that some consideration of the psychology of organizations may be necessary to ensure that the problems of human error are given the degree of consideration they require.