An Aircraft System Safety Analysis Method Based on Fault Propagation

Traditional safety analysis methods suffer from strong subjectivity, low consistency, and high workload. To solve these problems, this paper proposes a safety analysis method for aircraft systems based on fault propagation. First, this study establishes nominal and extended models of aircraft systems in Simulink. The modeling relies on system mathematical models and typical fault modes, and the built models act as a fault injection platform. Second, a monitoring module is developed in Simulink. This module monitors the performance responses of components and systems after fault occurrence and automatically judges fault effects. Third, fault combinations of each subsystem are injected to explore their impacts on adjacent subsystems. On this basis, fault propagation paths are derived, and the minimal cut sets (MCS) of system top events as well as their occurrence probabilities are obtained. Finally, the lateral control system of a certain aircraft is taken as an engineering case for verification. A comparative analysis is conducted between the proposed method and the classical state traversal method. The results indicate that the proposed method greatly reduces the number of fault combinations in an exponential manner while guaranteeing analysis accuracy. It therefore improves the efficiency of system safety analysis significantly.