The system consists of a network of optical fibres carrying digital optical signals forming control commands for the aircraft's elevators etc. The control commands are produced by control elements (9) and pass via signal processors (10) to the network, which carries them to servo units (14). The processors are coupled to mixers and to a data system. The servo units are addressable. The power supply system comprises several separate power sources each of which can be switched in independently. The power sources may be a jet engine (8), an auxiliary turbine, a wind-driven turbine or a battery. Each power source has its own switch and own monitor each of which is connected via three (redundancy) parallel transmission units to the control network. The control network connects them to a test unit that controls and monitors the units. The advantage of using optical fibres lies in avoiding the effects of delays, reflections and stray electromagnetic fields experienced in conventional electric cable or wire networks. The system also performs preprogrammed safety operations if a component or unit fails. Safety in general is increased. To this end the supply transmission units are provided in triplicate to raise the level of safety of the supply system to that of the control system.
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