Fault Tree Analysis of an Airborne Refrigeration System Based on a Hyperellipsoidal Model

The airborne refrigeration system is an important subsystem in aircraft environmental control. The increasing complexity of this subsystem means that cabin temperature issues are sufficiently complex to exhibit various faults during operation. In this study, a fault tree analysis is applied to establish a model based on the fault mechanisms of an airborne refrigeration system to improve its reliability. Considering that the probability of occurrence of all basic event faults in the interval of operation is extremely low and that the probability decreases as the number of basic events increases, a new method of fault tree interval analysis is proposed. Based on the hyperellipsoidal description of uncertain variables, the reliability evaluation of the system can be realized using a two-layer Monte Carlo sampling method. Accordingly, the failure modes that are most likely to occur are determined by importance analysis, providing conclusions that can help to improve system reliability and performance.