Analysis of Cascading Impact of Angle of Attack Signal Failure in Flight Control System of Civil Aircraft

The angle of attack (AOA) sensor for civil aircraft is generally installed on both sides of the front fuselage. It measures the angle of attack of the aircraft by sensing airflow and has a heating function to prevent freezing under icy weather conditions. The AOA signal usually adopts a redundant design. The AOA signal sent by the angle of attack sensor is processed and logically calculated or voted by the flight control system computer before being transmitted to the user system to realize functions such as stall warning logic judgment. The flight control system of civil aircraft has high reliability requirements for the angle of attack signal. After receiving the redundant angle of attack signal, the flight control system monitor the validity, comparison, and voting/selection calculation of the angle of attack signal. When comparing redundant angle of attack signals, if the difference between a certain angle of attack signal and any other angle of attack signal exceeds the monitoring threshold, it is considered that there is a fault in this angle of attack signal. By establishing principles for determining failure scenarios, judging direct effects, analyzing indirect effects, and analyzing the effect of AOA signal failure on the flight control system, the problem of classifying the effect of AOA signal failure based on cascading effect analysis technology is studied. By analyzing the architecture and function of the flight control system, the failure mechanism is determined, and the failure scenario is defined. Through cascading effect analysis technology, the effect of AOA signal failure on the flight control system is analyzed to support the comprehensive safety assessment of the entire aircraft, providing technical support for the classification of AOA signal failure impact.