Design of fault diagnosis expert system for civil aircraft based on FTA-BDD analysis

According to the different types of faults of the complicated system of civil aircraft, this paper designs a kind of fault diagnosis expert system based on the fault tree analysis. The designing method of each module of knowledge base is given in detail, and the process of calculation is simplified through direct binary decision diagrams (DBDD) method which analyzes component probability importance. The problem of confliction of rules is also solved effectively by introducing a priority coefficient combined with component probability importance and fault diagnosis time. Landing gear retraction system is an example in order to analyze and explain the feasibility of the design of fault diagnosis expert system for civil aircrafts.