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Nimrod AEW3

The Navy's decision to phase out fixed wing operations during the early 1970s led to the task of providing Airborne Early Warning [AEW] cover to the fleet being transferred to the Royal Air Force. It was decided that twelve low hour Shackleton MR Mk 2s would be converted as an "interim solution" until a new purpose built aircraft could be procured. Again, the same podded AN/APS 20 radar sets were fitted to the Avro designed airframes and No. 8 Sqn was declared operational with the Shackleton AEW2 at Lossiemouth in 1972.

Throughout the 1970s the need to replace the ageing Shackletons gathered pace. In August 1972, the RAF issued an AST to replace its Airborne Early Warning (AEW) variant of the Shackleton operated by No. 8 Squadron. This airborne early warning aircraft was developed from the Nimrod MR2 which was developed from the Comet airliner. All three of which can be similarly recognized, although the AEW has the bulbous nose and tail boom that houses radar equipment. Manufacturing AEW aircraft is extremely challenging.

Boeing was offering the Boeing 707 based E-3A to all NATO countries interested in providing its own AWACs / AEW. It was soon realised that the cost of the E-3 was way beyond the budgets of most member nations so Boeing then offered the aircraft to NATO. However, the inability of the member nations to come to an agreement on how and when this fleet of aircraft would be operated led to the British Government to go it alone in 1977.

In March 1977, the procurement was announced of a specialised version of the Nimrod. This variant would have a large bulbous radome in the nose and tail to house Marconi scanners providing 360 radar coverage. Unlike the American solution of a single radar antenna mounted in a rotating radome high above a Boeing 707 fuselage (which resulted in small "blind spots" directly below the aircraft), Hawker Siddeley decided to have a GEC Avionics two-antenna system mounted in the nose and tail of a Nimrod airframe. The scanners would work together each providing 180 degrees of uninterrupted coverage of the surrounding airspace. Initial tests of the system were carried out aboard a converted Comet 4 airliner. This aircraft was only fitted with the forward scanner and following its first flight in 1977 with its new bulbous nose profile, development work began on the new system.

Three AEW3 development aircraft were manufactured and the first of the eleven Nimrod AEW-3s to be completed made its maiden flight from Woodford on 16 July 1980. A production batch of eight Nimrod AEW3 aircraft was then laid down using a further eight redundant Nimrod MR1 airframes. The first flew on 9 March 1982 and by late 1984 the first 'interim standard' Nimrod AEW3 aircraft was delivered by British Aerospace to No. 8 Squadron to allow crew training to commence.

The original Nimrod air-to-air refueling [AAR] installation was fitted during the Falklands conflict in 1982. Subsequently, the MOD decided to upgrade the AAR system and move the refuelling pipes, for the most part, out of the cabin and into the bomb bay. In 1985, in the course of the AEW3 program, which was also required to have an AAR capability, the AAR system design was refined, to enable its incorporation as a formal modification to the aircraft design. During the initial incorporation of AAR into the AEW3, one of the fuel system design features which was considered by British Aerospace was the effect of the fuel tank blow-off valves. These valves are fitted to all, bar two, of the aircraft's fuel tanks and operate as pressure relief valves: should the pressure in a fuel tank exceed a prescribed limit, fuel is ejected from the tank through the valves to the atmosphere. The blow-off outlet for the No. 5 tank is situated forward of the port engine intakes and there was concern that, should fuel be ejected during AAR, it might enter these intakes. Therefore, the No. 5 tank blow-off valve was disabled to prevent this occurring. Nonetheless, the AEW3 flight trials team noted that there was a potential risk from other blow-off valves, including that of No. 1 tank, and recommended investigation to determine the effect should blow-off occur from these tanks. Unfortunately, it appears that the subsequent demise of the AEW3 project led to these recommendations remaining on the shelf, and potential sources of fuel blow-off and overflow during AAR remained unremedied.

It was also decided that the Nimrod would be made available for sale to NATO to fulfil their requirement once development was complete. (Subsequently NATO decided to order the American solution and deliveries of the ten E-3A aircraft began at Geilenkirchen, Germany in 1982). What followed has filled many volumes. The Nimrod was to have provided for Britain's early warning needs, and would have been compatible with the NATO AWACS. However, the Nimrod suffered from serious technical ?awsand major cost overruns.

In the summer of 1986, the British Government opened a competition for a system to fulfill its early warning needs. Seven companies submitted bids to the Ministry of Defence: Boeing (AWACS), Grumman (E-2 Hawkeye and Nimrod fitted with U.S. avionics), Lockheed (P-3 Orion), Airship Industries, Pilatus Britten-Norman, MEL (a subsidiary of Philips Electronics), and GEC Avionics (Nimrod AEW.3). It is important to note that had the British been successful in developing their own early warning system, the Nimrod AEW.3, the radar for which has been under development at GEC since 1977, there probably never would have been any competition at all. When the U.K. opened its airline early warning competition, Boeing submitted a preliminary offset bid of 35 percent of the "contract value. But in July, 1986 this offer was increased to 100 percent of the contract value, which is the normal minimum acceptable to the British Government.

In September, 1986, the Ministry selected two of the seven bidders as semi-finalists, the GEC Nimrod and the Boeing AWACS, stressing that only these two had the potential to meet all of the Royal Air Force's requirements. According to Lord Trefgarne, British Minister of Defence for Acquisition, the selection of the two finalists was based on demonstrated capabilities, the amountof risk foreseen in completing development, cost, and the amount of time needed for completion. At this time, France, which was also considering an early warning purchase, joined Britain in theevaluation of the two early warning systems.

In November, 1986 Boeing and its subcontractors (including Westinghouse, G.E. and SNECMA) again upped the offset offer to 130 percent of the contract value over eight years if AWACS were selected. This figure was the highest ever made by Boeing in an international competition. By this time, Boeing had already negotiated participation agreements with three British avionics companies -- Plessey, Ferranti, and Racal -- and these firms publicly supported AWACS over the Nimrod. These firms were not participants in the Nimrod program. The "agreements" were vague, simply stating the intent to cooperate in any offsets that may result if the AWACS were eventually selected by the UK. However, the fact that three of Britain's largest aerospace-related firms favored the AWACS played the important role of making an American buy seem less onerous. The Risk Assessment Group of the British Ministry of Defence, an internal committee which studies technical risks in new programs, also came out in favor of the AWACS.

After years of rising costs and delays due to the inability of the radar to work to specification the decision was made by the Government to cancel the order for the Nimrod solution. On 18 December 1986 the ill-fated Nimrod Airborne Early Warning project was finally cancelled after numerous delays and setbacks. It was also announced at the same time that Britain was procuring the Boeing E-3D Sentry as the Shackleton replacement - 6 (later changed to 7) Boeing E-3 Airborne Warning and Control System (AWACS) aircraft were ordered.

This came despite the fact that over $1.37 billion had already been spent by the Government to research and develop the Nimrod. The Nimrod AEW3 airframes were stored at RAF Abingdon until they were scrapped in the 1990s.

According to the British Govemment, the decision was made solely on the system's proven ability to meet the country's defense requirement. This decision resulted in public outrage, especially by GEC, that the negative implications were "tremendous" for the British electronics industry, including loss of over 2,500 prime and subcontractor jobs and a substantial future export market for early waming devices. But the British Minister of Defence, George Younger, in announcing the AWACS decision to the House of Commons, held that the gains for other British firms will equal or even exceed losses to GEC.

Lord Levene of Portsoken, who was then the Chief of Defence Procurement and also the National Armaments Director, later recelled the Government " ... had got to the stage where we had written off 500 million. "We cannot stop now. We have written off 600 million. We cannot stop now. We have written off 700 million. We cannot stop now." I then walked in and we had to decide that that project unfortunately was not going to work. We were forced to buy in the United States. It is a very difficult issue."

Richard D. Fisher, Jr., Senior Fellow, International Assessment and Strategy Center, stated in 2010 that "Britain's Marconi apparently sold at least one example of its Argus radar from the cancelled Nimrod AEW program, which China placed on a modified Russian Ilyushin Il-76 transport. Then in the mid-1990s Britain's Racal Co. sold six of its Skymaster lightweight naval airborne early warning (AEW) radar, which still fly on the PLA Navy Air Force's Y-8J aircraft. Ostensibly sold to help China "combat piracy," by 1999 the Y-8J was observed in exercises providing long-distance cuing for ship-launched anti-ship missiles."

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Page last modified: 11-07-2011 03:02:48 ZULU