Nimrod R1

Originally designed as a maritime patrol and anti-submarine aircraft, the Nimrod has become famous for its role in support of many air-sea rescues. Less well known is the secondary role for which a number of aircraft were adapted. The original maritime equipment was removed from the airframe, and replaced with a highly sophisticated and sensitive suite of systems used for reconnaissance and the gathering of electronic intelligence. The ability of the Nimrod to loiter for long periods, following a high speed dash to the required area of operation, make the aircraft ideally suited to this task.

Three additional airframes were also ordered from Hawker Siddeley to replace the ageing Comet R2s still used by the RAF for Electronic Intelligence (ELINT) duties. The first of these three extra airframes was delivered to RAF Wyton in July 1971. They were each fitted with a suite of sophisticated and sensitive electronic intelligencegathering equipment and antennae and were designated Nimrod Reconnaissance Mk 1 (Nimrod R1). The principal external difference from the maritime Nimrod was that they did not have the Magnetic Anomaly Detector probe fitted in the tail. The three original Nimrod R1s were built by Hawker Siddeley at Woodford and delivered to the RAF between 1970 and 1973. There are currently three Nimrod R1s in existence, operated by No. 51 Squadron from RAF Waddington.

In 1995, a Nimrod R1 (XW666) was lost following an engine fire. It was replaced in December 1996 by the conversion of a Nimrod MR2 (XV249), then in storage at RAF Kinloss, into a Nimrod R1. The Nimrod R1 played a key role in the Falklands Conflict of 1982. Its increasingly important electronic intelligence (ELINT) capabilities have been employed in almost every conflict involving UK forces since then.

The flight profiles of the Nimrod MR2s and R1s have been very different. The maritime patrol work of the Nimrod MR2 has required it to fly 'in the weather' and frequently at low level (200-300 feet) over the sea, causing the structure to fatigue at a faster rate than for normal cruise flight profiles. By contrast, the R1 has tended to fly only at high level and, therefore, in a structurally more benign environment. As a result, the fatigue and corrosion levels of the MR2s have been greater than the R1s. The corrosion suffered is not only evident on the structure but on some components, such as elements of the fuel system.

The original decision to withdraw the Nimrod R1 from service was taken in 2008 by the previous Government. Some members of Parliament expressed concern about the future of the BAE Systems Woodford production plant and aerodrome bordering the Macclesfield constituency and the Ministry of Defence's Project Helix decision to replace three Nimrod R1 aircraft with US RC-135 Rivet Joint Boeing jets instead of the MRA4, nine of which were being assembled at Woodford. They noted that 400 million had been budgeted for the Helix Programme with the decision on the future of the United Kingdom's large aircraft capability centering on two options, first to upgrade and modify the existing airframe and, secondly, to use the new MRA4 platform. They further noted that while BAE Systems would be involved in both options, the Woodford plant would only benefit from the commissioning of the MRA4 platform. While they recognised that BAE Systems considers the cost of revamping the R1 fleet to be a lot greater than using the MRA4 platform, the also acknowledged that BAE Systems' experience demonstrated that there is considerable risk in stripping down aeroplanes, with projects often incurring extreme cost and time overruns. They believed that the MRA4 option continues to give the RAF the best capability, best in-service date and best value for money for HM Exchequer; and noted with deep concern that due to the current state of the defence budget the RAF plans, at a cost of 700million, to replace three 35 year old Nimrod R1 aircraft based at RAF Waddington, near Lincoln, with even more antiquated US RC-135 Boeings, which entered service with the US Air Force 46 years ago.

In March 2010, the Ministry of Defence signed an agreement with the US Government to purchase three Rivet Joint aircraft and associated training and ground systems as a replacement for the Nimrod R1. The capital cost of procuring the Rivet Joint fleet is around £650 million. Estimated logistic support costs up to 2025 are £590 million, which includes regular capability updates. Rivet Joint is replacing the Nimrod R1 aircraft. The annual estimated logistic support cost that can directly be attributed to the Nimrod R1 fleet in its last full year of service life (2009-10) is £18 million. This figure does not include the costs of managing obsolescence and updating capability which were incurred throughout the life of the aircraft; such costs are included in the Rivet Joint figure. Rivet Joint provided best value for money when compared to all other options. It will provide an assured capability through-life, able to cope with evolving threats, and will be substantially more capable than the current Nimrod R1 aircraft.

After the withdrawal of the Nimrod R1 on 31 March 2011 the following airborne intelligence, surveillance, target acquisition and reconnaissance capabilities will remain available to assist British armed forces: Sentry, Sentinel, Tornado GR 4 when fitted with a RAPTOR or Litening III pod, Typhoon when fitted with a Litening III pod, Sea King Mk7, Reaper Remotely Piloted Air System and Hermes 450 UAS.

On 14 March 2011 the Secretary of State did confirm that the military had been tasked with assessing whether there could be a temporary extension in service of the Nimrod R1 signals intelligence aircraft, which was due out of service in 2011. Although not directly linked by the MOD to current events, several analysts have suggested that the decision is related to discussions over the establishment of a no-fly zone over Libya. In view of current events in Libya one Nimrod R1 aircraft is being kept in the region for up to three months in support of UNSCR 1973. This is a pragmatic decision given the aircraft is already in the region but is subject to continuous review of the Alliance's operational requirement.

RAF Units

• 51 Squadron, RAF Waddington - 2 Nimrod R1