Research On The Application Of Compositional Safety Analysis Technology In Modern Airborne System Design Process

Traditional safety analysis techniques, like FTA and FMEA, cannot meet the requirements of the modern airborne system failure dynamic. Compositional safety analysis methods can partially satisfy the airborne system failure characteristics, not completely. Based on the existing compositional safety analysis methods, this paper use Start Chart to describe and analyze system failure dynamic, which can overcome the drawbacks of Compositional safety analysis methods.This paper first summarized the characteristics of airborne systems failures, introduced four existing compositional safety analysis methods. At the base of analyzing the shortcomings of describing characteristics of airborne systems failures in the existing four methods, the paper proposed that using state chart to describe the state transition of system, driven by failure event, which can satisfy the requirements. Through State Chart the paper establishes a qualitative analysis method to calculate the minimum cut-sequence. The method needs acquiring sequence expression from transition path of Start Chart, and then reduces the expression with reduction rule and the minimum cut-sequence is obtained. Finally, this paper took aircraft wheel braking system of PSSA stage for the application object, applying the state chart to describe dynamic failure and solve the minimum cut sequences, which prove the rationality of the method. Compared with the traditional minimum cut sets from FTA, the minimum cut sequences are more accurate for system dynamic failure description.