Effect of Improving Accuracy of Load Monitoring on Aircraft Probability of Failure

Abstract

Evaluating risk of aircraft failure is necessary for scheduling appropriate maintenance, avoiding aircraft losses and mission failures, maintaining a high level of readiness, and estimating aircraft fleet aging. This paper presents the results of calculating aircraft failure risk by estimating the probability of structural failure of F-18 wing attachment bulkheads. Laboratory fatigue-crack growth-test data (published in open literature) are utilized to describe the distribution of initial defects, which is then evolved as a function of applied loads and flight hours. The risk is calculated as a probability of failure (POF) during a single flight, and it is shown that the effect of uncertainty in the knowledge of applied flight loads on POF is significant. The reported results provide a framework for evaluating benefits of improving accuracy of load-monitoring data and POF.