Eurocopter conducted the first flight of an EC135 featuring a fibre optic-based flight control system late last month.

The system is being tested on an EC135 designated the Active Control Technology demonstrator/Flying Helicopter Simulator (ACT/FHS), developed by Eurocopter Deutschland and Liebherr as part of a technology programme with German research centre DLR, the German armed forces test centre, and part-funded by the German defence ministry.

The "fly-by-light" system is a "quantum leap in helicopter flight control" compared with traditional mechanically-based flight control, says Eurocopter. In fly-by-light, signals between the pilot's inceptors, the flight control computer and rotor-blade actuators are transmitted via optical fibres rather than electronically along wires. Electrical flight control - traditional fly-by-wire - has been developed by Agusta, Eurocopter and Stork-Fokker for the NH Industries NH90 helicopter, but last month's flight, near Munich, marked the first test of fibre-optics by Eurocopter.

The advantages of optical transmission compared with the electrical equivalent include immunity to electromagnetic interference, a much broader transmission spectrum which will enable future development of demanding flight control and missions systems, and low weight, says Eurocopter.

Fibre-optics have been used in military aircraft, but not widely in commercial aerospace due to cost and environmental factors.

Source: Flight International