There are three major challenges in inertial data redundancy management for flight control systems: common-mode risk suppression, correct voting on singular faults, and single data available. This paper proposes a fault detection algorithm and a redundancy management architecture based on motion dissimilar monitoring. The core of this architecture lies in establishing the relationships among attitude, angular rate, load factor, and body-axis acceleration through engineering-oriented soft-reconfiguration calculations based on simplified motion models. This enables effective fault detection in inertial data and enhances the safety of the flight control system. Real flight test data is used to construct a ground-based offline flight test verification platform, and flight data gathered under boundary flight conditions is used to evaluate the proposed algorithm. The results show that under normal inertial data conditions, the body-axis overload calculated theoretically based on the aircraft dynamics is highly consistent with the actual measured overload, with a maximum deviation of less than 0.1g. However, there is a noticeable difference between the measured and theoretically computed body-axis overload when any of the angular rate, overload, or attitude signals in the inertial data are faulty. This allows for precise fault identification and isolation without the addition of new hardware, effectively enhancing the safety of the flight control system.

To address the contradiction between the necessity of fault simulation flight testing for airworthiness compliance of civil aircraft flight control systems and the safety risks caused by fault injection in flight, this paper proposes a flight test fault injection system capable of covering all flight control system failure modes to meet airworthiness verification requirements. The system has undergone extensive flight validation and supports airworthiness certification for a specific civil aircraft model. A data hub for flight test equipment, a fault injection control trigger program integrated into the flight control computer, and a simplified, multi-mode human-machine interface testing panel comprise the core of the fault injection system, which ensures the compatibility and authenticity of fault simulations. In addition, the system accomplishes dependable handling of abnormal operating situations through a variety of distinct fault excitation cutoff methods, amplitude limiting mechanisms, and monitoring protocols, thereby considerably improving safety and fault tolerance. Furthermore, a flight test simulation strategy targeting typical flight control system failures is presented. The feasibility of the proposed approach is ultimately verified through in-flight testing with onboard implementation.