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Circuit Module

Technical Information

Catalogue No: C0497
Category: Unknown
Object Type: Module/Sub-Assembly/Component
Object Name: Circuit Module
Part No: 7740-00021-RIG03
Serial No: 007
Manufacturer: Marconi Avionics
Division: Combat Aircraft Controls [CACD]
Platform(s): EAP 
Year of Manufacture: circa 1986
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Marconi Avionics Ltd
Ser. No 007


This Circuit Module was used in the Flight Control Computer system of the EAP (originally known as the ACA Advanced Combat Aircraft). Its function may be a Data Store
The module is also etched with: "6752-00313"; probably the part number of the bare circuit board

EAP's quadruplex-redundant digital flight control system is a development of that in the active control technology (ACT) Jaguar FBW test bed, the first digital fly-by-wire aircraft to fly without mechanical backup controls. The system has to withstand two critical failures. EAP has four identical flight control computers with no fewer than 13 control surfaces, the flight control computers will operate at more than three times the speed of Jaguar's. These computers house the flight resident software which stabilises the aircraft artificially then enables the pilot to fly it. In addition they house software for failure management, reversion logic, and built-in test.
Also included in the flight control system are two digital air data computers, four aircraft motion sensor units (AMSUs), and four actuator drive units (ADUs). While the foreplane, intake varicowl,
and wing leading-edge flaps are driven directly from the flight control computers, the flaperons and rudder are driven from the aft-mounted ADUs which are connected to the computers by serial digital databus.
The air data and motion sensors are also connected to the computers along two dual redundant 1553B multiplex digital databuses. The AMSUs consolidate roll, pitch, and yaw rate sensors in single boxes. The flight control computers pass on air data to the avionics and engine controls via EAP's two main digital data highways and additionally process motion sensor output to provide standby attitude and heading reference.
GEC Avionics is responsible for EAP's flight control system, supplying the four flight control and two air data computers, while Bodenseewerk supplies the four actuator drive units, and Litef the four aircraft motion sensor units.
The Company, in common with other suppliers, made equipment for the EAP at their own cost in anticipation of orders for the Typhoon. Around 6 to 8 sets of equipment were made and all were put through the full evaluation/qualification tests.

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