Study On Failure Modes Of Fuel System In Civil Aircraft Based On The LSA FMECA

Fuel system is one of the key systems of civil aircraft, which not only delivers fuel to the engine and APU but also adjusts the aircraft center of gravity and cools other equipments.Once the failure occurs, it will endanger the safety of flight. So the research on reliability and supportability of fuel system becomes a key point in the risk and safety analysis for civil aircraft.Based on logistic support analysis specification reguirements, fuel system failure modes were studied and a suitable LSA FMEA analysis process for aircraft system was established firstly in this paper, which is presented in detail.Then, on the basis of research on RPN and fuzzy comprehensive evaluation method, considering of the discreteness and imperfection of failure mode criticality indexes and the imbalance of quantitative and qualitative indexes, the data envelopment analysis(DEA)-based C2 R model for criticality analysis of LSA failure modes is presented. In the model, the criticality indexes for failure mode are constrained by allocating weights using the relative comparison method, which is used to improve the discreteness and irrationalities of traditional method in dealing with integrating the risk factors. After studying on algorithms, the simplex method approach was used tocalculate.Finally, the reliability and function block diagrams of fuel subsystems for certain type civil aircraft are constructed, and using the model a simplified case for the LSA FMEA and criticality analysis is accomplished in detail. Then a comparative analysis between the proposed approach and fuzzy comprehensive evaluation method is carried out, according to which a list of key failure modes of fuel system by the risk sequences of failure modes was obtained.At the same time, combining with the failure mode effects and criticality analysis process of fuel tank system based on the LSA FMECA, a software system for civil aircraft system failure mode analysis is developed.