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Jaguar FCS Actuator Drive & Monitor Computer

Technical Information

Catalogue No: C0954
Category: Flight Control
Object Type: Signal/Data Processor
Object Name: Jaguar FCS Actuator Drive & Monitor Computer
Part No: 49-060-10
Serial No: 106
Manufacturer: Marconi Avionics
Division: Unknown
Platform(s): Jaguar FBW
Year of Manufacture: Unknown
Dimensions: Width (mm): 123
Height (mm): 195
Depth (mm): 425
Weight (g): 8,560
Location: Rack RAA01 [Main Store]

Actuator Drive & Monitor Computer


This unit is a late unit with configuration -10.

 The Jaguar was the result of an Anglo-French collaboration to develop an advanced training and strike aircraft, entering service with the Royal Air Force in 1973.
XX765 was withdrawn from RAF service to demonstrate the feasibility of Active Control Technology (ACT), under development by British Aerospace (BAe). The aircraft's normal control rods were replaced with a 'fly-by-wire' (FBW) control system, which used four independent computer-controlled electrical channels to relay instructions to the flight surfaces. The aircraft was further modified by fitting large leading edge strakes (wing extensions) to move the centre of lift forward and adding ballast to the rear fuselage to move the centre of gravity aft. This enhanced the lift and drag characteristics and made the tail plane more efficient thereby allowing smaller lighter engines with greater fuel efficiency to be used, decreasing overall weight by 15% thereby greatly enhancing aircraft manoeuvrability – important to the next generation of air superiority fighters.
Flight trials began in October 1981. Test pilots were impressed by the crisp control responses and smooth flight. The aerodynamic instability of the aircraft enhanced manoeuvrability, but the computer-controlled flight commands provided split-second corrections to compensate for the unstable configuration.

The aircraft first flew on 20 October 1981 and was the first aircraft to fly with an all digital FBW flight control system with no form of reversionary (back up) control. The test programme was completed in 1984 after 96 flights, having successfully demonstrated concepts which were subsequently incorporated into the Typhoon and Boeing 777 FBW flight control computers produced by the company.

The Actuator Drive and Monitor Computer provides control demands to the servo valves of the control-surface actuators developed by Dowty Boulton-Paul. The servo valves control the position of the first-stage valves that are mechanically summed before applying demands to the control valves which modulate the position of the Actuator control ram. Linear variable differential transformers (LVDTs) measure the position of the first-stage actuator and output ram positions of each lane and these signals are fed back to the flight control computers, thereby closing the loop.

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