Abstract: The suspension weights of a fighter alters the actual service load for each take-off. How the variation of take-off suspension weights affects the structural fatigue life is investigated through surveying actual flight parameter recorder (FPR) data. For the fighter involved in the investigation, scatter in fatigue damage caused by take-off suspension weights during one flight can reach 27% of the design criteria. The investigation shows that actual take-off suspension weights chang considerably and irregularly, so it is important to calculate fatigue damage based on actual suspension weights for each flight. Analysis results of the complete recorded FPR histories for three aircrafts show that the actual fatigue damages are about 20% lighter than the design assumption, which provide technical support for extending individual aircraft service life based on load/life monitoring.

Key words: aircraft life, life monitoring, suspension weight, load history, fatigue, damage