S-92 Fly-by-Wire Advanced Flight Control System

Incorporation of Advanced Flight Controls (AFC) into the S-92 adds even more capability to this modern, high performance and versatile helicopter. The full-time, full-authority, fly-by-wire (FBW) system now under development replaces conventional mechanical linkages between pilot control sticks and aircraft actuators with redundant electronic channels. FBW technology enables the use of advanced control laws that enhance performance, increase mission capability and reduce pilot workload while providing extremely fault tolerant ADS-33 Level 1 handling qualities. In addition, the new system removes significant weight from the vehicle, reduces direct maintenance costs, and offers operational enhancements. The S-92 advanced flight control system utilizes three redundant channels, each with self-checking processing pairs and duplicate input/output signal paths. Channels receive pilot input and aircraft state information and calculate commands to drive main and tail rotor actuators. In the event of a failure, fault detection and isolation algorithms automatically remove any failed components from the actuator drive path. Robust partitioning has been built into the flight control computer ensuring a diverse range of aircraft functions, including vehicle management functions, can safely be executed in every microprocessor. Since the S-92 accomplishes a wide array of missions, the FBW system addresses both military and civil requirements. Development of the FBW system began in 2002 and will culminate with FAA Part 29 certification in the 2007 timeframe.