ABSTRACT
The analysis finds that the fatigue design of the critical part was not at fault: the provided magnitude of life expectancy was to assure a long uninterrupted performance. The reason for a sudden failure seems to lie in another factor with as strong effects on fatigue life, namely, the surface condition of a part. Fatigue failure begins in most cases at the surface which bears the greatest load and is exposed to environmental effects. The investigating team came to a conclusion that the cause of the accident was the fatigue fracture of a fuse pin—part of a pylon mounting. Satisfied with the result thus obtained, the investigation turned to another factor most affecting fatigue life—the surface integrity of the part. Fatigue failure begins in most cases at the surface which bears the greatest load and is exposed to environmental effects.
