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RB199 Main Engine Control Unit

Technical Information

Catalogue No: C0273
Category: Engine Control
Object Type: Signal/Data Processor
Object Name: RB199 Main Engine Control Unit
Part No: 22-001-01A/R01A
Serial No: 002
Manufacturer: Marconi-Elliott Avionic Systems Ltd
Division: Unknown
Platform(s): Tornado
Year of Manufacture: circa 1973
Dimensions: Width (mm): 194
Height (mm): 197
Depth (mm): 454
Weight (g): 12,580
Location: Rack RAA01 [Main Store]

Marconi-Elliott Avionics
RB199 M.E.C.U.
Type 22-001-01A/R01A
Ser 002
Code K0656


Two of the RB199 engines are fitted to the Tornado and provide outstanding performance. In order to meet the many different mission requirements of the Tornado, in particular extreme low-level missions, a 3-shaft design with afterburner and thrust reverser was selected. Each engine is controlled by a Main Engine Control Unit (MECU)which reduces the pilot’s workload during operation and supports on-condition maintenance. The MECU has two independent lanes of dry engine control and a single reheat control lane.
The original design of the MECU was by Rolls Royce but they gave the production contract to Lucas Aerospace but according to Flight International (14th May 1977) it appears that Lucas went in for ambitious advanced avionics, while the schedule required Turbo-Union to produce a flight cleared box for the Vulcan flying testbed early in the programme and later for the Tornado. During that period, 1973-74, Turbo-Union commissioned a fall-back system from Marconi-Elliott.
The Marconi-Elliott prototype system was highly regarded and did what it promised to do,whereas the Lucas equipment was less sophisticated but had done substantial flight testing and which was a lower risk when developed to high electronic standards for service use. It was a choice between the low-hour, advanced box or the more tested prototype. So the Lucas item was selected and subsequently improved.

The Tornado originally came in two variants; the Interdictor Strike Version (IDS) for the German, Air Force and Navy, Italian Air Force, and the Royal Air Force, and the Air Defence Variant (ADV) for the Royal Air Force only. Marconi-Elliott Avionic Systems provided a wide range of equipment for both variants.

• Digital Autopilot Flight Director System (AFDS)in conjunction with Aeritalia, Italy
• Command Stability Augmentation System (CSAS)  in conjunction with Bodenseewerk, Germany
• Quadruplex Actuator Integrated into Fairey Hydraulics power control unit
• Stores Management System (SMS) in conjunction with Selenia, Italy
• Fuel Flowmeter System in conjunction with Teldix, Germany and OMI, Italy
• TV Tabular Display System in conjunction with AEG Telefunken, Germany
• Combined Radar and Projected Map Display (CRPMD) from Ferranti
• E-Scope Display System
• Triplex Transducer Unit
• Central Suppression Unit
• Engine Control Unit

By 1980 the Enhanced E-Scope Display (EESD) was under development. This was was a digital design with a frame store, rather than the analogue design and long persistence phosphor CRT of the original E-Scope Display (ESD). The EESD part number was 79-061-xx and this version was probably fitted to the majority of Tornado IDS aircraft.

RAF IDS variants were initially designated the Tornado GR1 with two variants called the Tornado GR1A and Tornado GR1B; the Tornado F3 was yet another version.

The contract covering the development and production investment for the Royal Air Force's mid-life update (MLU) for their 229 Tornado GRl and F3 aircraft was signed in April 1989. The upgrade included the following:

• Introduction of a new avionics architecture built around a 1553 databus.
• New sensors & Displays consisting of a Forward Looking Infra-red sensor, a Pilot's Multi-Function Display with digital map, wide angle HUD, Computer Symbol Generator, Video recording System and a Computer loading System.
• New Armament Control System consisting of a Stores Management System, a Weapon Interface Unit linked to a 1553 databus within a 1760 interface.
• A Night Vision Goggle compatible cockpit and the aircraft is also equipped with Forward Looking InfraRed (FLIR)
• Terrain Reference Navigation /Terrain Following Display/Terrain Following Switching & Logic Unit /Covert RadAlt.

Ferranti won the contract for the new HUD, Active Matrix Liquid Crystal Displays (AMLCD) to replace the TV Tabs, EHDD and E-scope. To support the new avionics a new Computer Signal Generator (CSG), with several times the computing capacity of the original Tornado main computer, and using the new high level ADA progamming language was procured

The Ferranti Nite-Op jettisonable NVGs were also procured under a separate contract.

In the event the MLU project stalled. In March 1993 a new Mid-Life Upgrade (MLU) project was launched and in1994 the UK signed a contract for MLU of GR1/GR1A/GR1Bs to GR4/GR4A standard.

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