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EAP Air Data Computer

Technical Information

Catalogue No: C0155
Category: Air Data
Object Type: Signal/Data Processor
Object Name: EAP Air Data Computer
Part No: 50-078-01
Serial No: 0005/85
Manufacturer: GEC Avionics
Division: Unknown
Platform(s): EAP 
Year of Manufacture: 1985
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Marconi Avionics Limited
ADC (SP-B-27-B204)
Part 50-078-01
Ser 0005/85
Code K0656
GEC Avionics Limited
Software Standard
Part SVID 0905
Ser 0005/85
Code K0656


Air data systems provide accurate information on quantities such as pressure altitude, vertical speed, calibrated airspeed, true airspeed, Mach number, static air temperature and air density ratio. The computer uses data from sensors such as the pitot-static system hence the ‘pressure’ connectors. The ADC is a key avionic system and forms part of the essential core of avionic sub systems required in all modern aircraft, civil or military.

This unit is marked ‘Software Standard SVID 0905’

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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