Abstract:With the advancement of intelligent aviation systems, modern aircraft demand higher levels of real-time responsiveness and autonomous diagnostic capability from flight control systems. As a critical actuator component, failures in the electrically controlled rudder surface can directly affect flight stability and safety. To enhance detection accuracy and response efficiency, this study proposes a fault detection model combining multi-scale convolutional neural networks (MSCNN) and long short-term memory (LSTM) networks. A multi-stage signal denoising mechanism is integrated to optimize feature extraction. The model is trained on multi-source flight data to accurately capture the temporal evolution patterns of key sequences such as voltage, current, and deflection angle. Experimental results show that the model achieves an accuracy of 96.7% and a miss rate below 1.08% after full training. It can generate high-confidence early warnings 2.2 seconds before the occurrence of abnormal events, demonstrating excellent timeliness and stability. Additionally, the model successfully identifies weak intermittent lag faults during typical cruise conditions with a classification confidence of 0.974, indicating strong early detection capability. The study confirms the robustness and practical applicability of the model under complex nonlinear scenarios and provides technical support for shifting fault diagnosis in flight control systems from passive response to intelligent prediction.