Dynamic fault tree analysis for digital fly-by-wire flight control system

Digital Fly-By-Wire (FBW) Flight Control System (FCS) is designed to achieve high level of reliability, frequently employ high level of redundancy. Dynamic redundancy employed in FEW system can realize complex fault and error diagnosis, recovery and reconfiguration. It is very difficult to analyze the reliability of the FEW system by traditional methods, such as Fault Tree Analysis (FTA) or Network Analysis. This paper describes dynamic fault-tree modeling techniques for handling these difficulties and provides a Markov Chain generation modeling method for coverting Dynamic Fault Tree to Markov Chain. The software failure of the FBW system can also be considered in the model. An example of a quadruple FEW redundant system and a Markov State Transition Chain software package (MSTCP) are given.