Notes:
Possibly used on the Sentinel Airship.
FARL demonstrated their Fly-by-Light system (in which fibre-optic cables are used instead of wires to pass signals between aircraft electronics boxes) at the 1980 SBAC show held at Farnborough. Following this they were approached by Airship Industries who were attempting to enter the military market, for which an airship is ideally suited for early warning, coastal surveillance and other long duration roles. The original system involved cables and pulleys and gave a heavy pilot workload as a result. Having realised that some form of electronic flight control system was required they ran into another problem that the airship was largely fabricated of non-conducting material and that the electrical cables would give dangerous lightning conductors.
GEC Avionics, under contract to Westinghouse, produced a fly-by-light control system for the Skyship 600, which made its maiden flight on October 23 1988. The control system was later fitted to the Sentinel 1000 which first flew in June 1991. A more advanced production standard control system was developed, ultimately for the Sentinel 5000 which was being designed to meet the requirements of the US Naval airship programme. The advanced system was installed on the Sentinel 1000 and made its first flight in April 1992. The system provides automatic stability augmentation control together with a full autopilot capability, whilst offering fail-operational capability to ensure continuous safe operation in the event of a malfunction. The fly-by-light system comprises two dual-channel flight control computers located in the gondola and linked by fibre optic cables to four dual channel actuator units. Each of these drives a surface actuator unit which consists of two independent brushless motors and gear trains with a common driveshaft which drives one of the four ruddervators.
The Flight Control Panel provides control and monitor functions for the Airship Auto-pilot.
