TRW Reports Progress with Flight-Control Power-By-Wire Alternatives

TRW, Inc. and its TRW Aeronautical Systems UK subsidiary are showing a wide range of advanced technology systems, among them several flight-control power-by-wire alternatives. They include electrohydrostatic actuation (EHA), electromechanical actuation (EMA), and an integrated actuation package (IAP. All aim to replace hydraulic power of primary and secondary flight controls by electrical operation.

Conventional fly-by-wire flight controls combine electrical signal inputs with hydraulic operation of the control surfaces by a complex network of high-pressure tubing. Power-by-wire aims to eliminate the hydraulic connection, and its associated risks, by providing electrical power straight to the actuators. Claimed benefits of the EHA, shown here by a demonstrator model, include enhanced survivability, plus reduced weight and aircraft ground service time.

TRW is also showing its fully-integrated control actuation systems technologies employed in the French Aster surface-to-air and joint advanced short-range air-to-air (ASRAAM) missile programs. These are among a wide range of next-generation TRW products in the areas of power generation, power management, flight controls, missile actuation, cargo handling, avionics, UAV and battlefield digitization systems.

Applying experience gained from providing the world's first variable-frequency electrical system on a civil jet aircraft, TRW is now focusing its efforts on developing a similar system for next-generation large aircraft such as the Airbus A3XX. As its Farnborough exhibits show, TRW has reduced system complexity by eliminating the hydro-mechanical constant-speed drive required in conventional constant frequency systems, for increased reliability and lower costs.

By John Fricker