PROBABILISTIC RISK ANALYSIS FOR AIRCRAFT STRUCTURES WITH LIMITED IN-SERVICE DAMAGES

摘要

This paper presents some recent results of NRC research on risk assessment for aircraft structures. First, this paper briefly reviews the Canadian Forces (CF) risk assessment requirements related to aircraft structural life assessment. Because the single flight probability of failure (SFPOF) (instantaneous failure rate) is an important parameter used in aircraft risk assessment, a critical review of different SFPOF definitions and calculations is presented. As the size of the CF aircraft fleet is relatively small, one common issue encountered during risk assessment is that only a limited number of in-service damage findings are available. Several methods are discussed for preparing input data, especially the initial crack size distribution (ICSD), from small samples for structural risk analysis. To demonstrate one of the in-service damage based methods, a risk analysis case study is presented, in which limited in-service damage findings were used to calculate the SFPOF at a wing location, in support of the CF risk-based decision-making on maintenance actions and the operational life limit.