Diagnostic of the avionic equipment based on dynamic fault tree

The diagnostic of avionic equipment on aircraft is based on the messages recorded during the flight. For a diagnostic establishment to a maintenance team, these messages are correlated with each others, thanks to specific rules. For example if message A and message B have been registered during the flight, then there are a failure, located on the equipment "n". Most of time, these rules are static, and do not integrate the dynamics of the failure and its implication on time relationship between recorded messages. Our study is based on the improvement of these rules by integrating the time dependencies between failure messages. The rules have been implemented, thanks to the formalism of dynamic fault tree. Nowadays dynamic fault trees are mostly used to evaluate the reliability of a complex system. Static gates as AND, OR, K-of-M... gates and dynamic gates as PAND, SEQ, FDEP, CSP, HSP, WSP... are used for reliability analysis. Our study is based on the use of dynamic fault tree to isolate all faults occurring on avionic systems. In the proposed approach, three new classes of dynamic gates are defined and an extension of fault tree analysis is developed. These gates are called "temporal sequences", "duration gates" and "counter gates".