Editing Hawker Siddeley Nimrod (section)

==Development==
[[File:Hawker Siddeley Nimrod MR1 (801), UK - Air Force AN1047063.jpg|thumb|Nimrod MR1 XV262 landing at [[RAF St Mawgan]] in July 1981]]

===MR1===
{{External media |topic= |width= |float=right |image1=[http://www.singas.co.uk/Charles_Jordan/Nimrod.jpg Circa 1967, Nimrod XV242 taxiing at RAF Changi during the type's test and evaluation phase in the Far East]}}

On 4 June 1964, the British Government issued [[List of Air Ministry specifications|Air Staff Requirement 381]], which sought a replacement for the aging [[Avro Shackleton]] [[maritime patrol aircraft]] of the [[Royal Air Force]] (RAF).<ref>Haddon-Cave 2009, pp. 16–17.</ref> Such a replacement had been necessitated by the rapidly-approaching fatigue life limitations accumulated across the Shackleton fleet.<ref>Jefford et al. 2005, p. 87.</ref> A great deal of interest in the requirement was received from both British and foreign manufacturers, who offered aircraft including the [[Lockheed P-3 Orion]], the [[Breguet Atlantic]] and derivatives of the [[Hawker Siddeley Trident]], [[BAC One-Eleven]], [[Vickers VC10]] and [[de Havilland Comet]].<ref name="chartres12">Chartres 1986, p. 12.</ref><ref name="Jefford et al. 2005, p. 131">Jefford et al. 2005, p. 131.</ref> On 2 February 1965, Prime Minister [[Harold Wilson]] announced the intention to order Hawker Siddeley's maritime patrol version of the Comet, the HS.801 as a replacement for Shackleton Mk 2.<ref>{{cite news |url=http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200384.html |title=Aircraft Decisions: Mr Wilson's Statement |work=Flight International |volume=87 |issue=2918 |page=224 |date=11 February 1965 |archive-url=https://web.archive.org/web/20130731130200/https://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200384.html |archive-date=31 July 2013}}</ref><ref>{{cite news |url=http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200849.html |title=The Maritime Comet |work=Flight International |volume=87 |issue=2924 |date=25 March 1965 |pages=465–466 |archive-url=https://web.archive.org/web/20130731124857/https://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200849.html |archive-date=31 July 2013}}</ref>{{refn|Following evaluation testing by the RAF, the Vickers VC10 had been identified as highly suitable for the task; however, an initial version of Comet-based Nimrod could be in service within five years, a more capable Nimrod equipped with the envisioned avionics would follow.<ref name="Jefford et al. 2005, p. 131"/>|group=N}}

The Nimrod design was based on the Comet 4 civil airliner which had reached the end of its commercial life (the first two prototype Nimrods, XV148 and XV147, were built from two final unfinished Comet 4C airframes). The Comet's [[turbojet]] engines were replaced by [[Rolls-Royce Spey]] [[turbofan]]s for better [[fuel efficiency]], particularly at the low altitudes required for maritime patrol. Major fuselage changes were made, including an internal weapons bay, an extended nose for radar, a new tail with [[electronic warfare]] (ESM) sensors mounted in a bulky fairing, and a MAD ([[magnetic anomaly detector]]) boom. After the first flight in May 1967, the RAF ordered 46 Nimrod MR1s.<ref name = "Fricker 593">Fricker 1972, p. 593.</ref> The first example ([[Royal Air Force Nimrod XV230|XV230]]) entered service in October 1969.<ref name="neal 119"/> A total of five squadrons using the type were established; four were permanently based in the UK and a fifth was initially based in [[Malta]].<ref name = "neal 119">Neal 1970, p. 119.</ref>

===R1===
{{Main|Hawker Siddeley Nimrod R1}}
[[File:Hawker Siddeley Nimrod R1 (801), UK - Air Force AN1554801.jpg|thumb|Nimrod R1 XW665 landing during [[Waddington International Airshow]] in [[Lincolnshire]] in 2009]]
Three Nimrod aircraft were adapted for the [[signals intelligence]] role, replacing the Comet C2s and [[English Electric Canberra|Canberra]]s of No. 51 Squadron in May 1974.<ref name="AIJul01 p31">Lake ''Air International'' July 2001, p. 31.</ref><ref name = "Fricker 594">Fricker 1972, p. 594.</ref> The R1 was visually distinguished from the MR2 by the lack of a MAD boom.<ref>Haddon-Cave 2009, p. 17.</ref> It was fitted with an array of rotating dish aerials in the aircraft's bomb bay, with further dish aerials in the tailcone and at the front of the wing-mounted fuel tanks. It had a flight crew of four (two pilots, a flight engineer and one navigator) and up to 25 crew operating the SIGINT equipment.<ref name="AIJul01 p30-1">Lake ''Air International'' July 2001, pp. 30–31.</ref>

Only since the end of the [[Cold War]] has the role of the aircraft been officially acknowledged; they were once described as "radar calibration aircraft". The R1s have not suffered the same rate of fatigue and corrosion as the MR2s. One R1 was lost in a flying accident since the type's introduction; this occurred in May 1995 during a flight test after major servicing, at [[RAF Kinloss]]. To replace this aircraft an MR2 was selected for conversion to R1 standard, and entered service in December 1996.<ref name="AIJul01 p34">Lake ''Air International'' July 2001, p. 34.</ref>

The Nimrod R1 was based initially at [[RAF Wyton]], Cambridgeshire, and later at [[RAF Waddington]], Lincolnshire, and flown by [[No. 51 Squadron RAF|51 Sqn]]. The two remaining Nimrod R1s were originally planned to be retired at the end of March 2011, but operational requirements forced the RAF to deploy one to [[RAF Akrotiri]], Cyprus on 16 March in support of [[Operation Ellamy]]. The last flight of the type was on 28 June 2011 from RAF Waddington, in the presence of the Chief of the Air Staff, ACM Sir Stephen Dalton.<ref name=dmj-r1>[http://www.defencemanagement.com/news_story.asp?id=16738 "Nimrod R1 makes final flight"] {{webarchive|url=https://web.archive.org/web/20120325162031/http://www.defencemanagement.com/news_story.asp?id=16738 |date=25 March 2012 }} ''Defence Management Journal,'' 28 June 2011. Retrieved 28 June 2011.</ref><ref>[https://www.bbc.co.uk/news/uk-13942014 "Nimrod R1 aircraft in final flight for RAF."] ''BBC,'' 28 June 2011. Retrieved 13 July 2011.</ref> XV 249, the former MR2, is now on display at the RAF Museum Cosford, West Midlands. The R1 was replaced by three [[Boeing RC-135|Boeing RC-135W ''Rivet Joint'']] aircraft, acquired under the Airseeker project; the first aircraft was delivered in late 2013.<ref>[http://www.flightglobal.com/news/articles/pictures-first-raf-rivet-joint-aircraft-arrives-in-uk-392875/ "PICTURES: First RAF Rivet Joint aircraft arrives in UK."]''Flight Global.'' Retrieved: 18 December 2013</ref>

===MR2===
[[File:Nimrod - RIAT 2006 (2424167612).jpg|thumb|Nimrod MR2 XV254 at a steep bank while displaying at the Royal International Air Tattoo, 2006]]
Starting in 1975, 35 aircraft were upgraded to MR2 standard, being re-delivered from August 1979.<ref name="Don World p95">Donald 1996, p. 95.</ref> The upgrade included extensive modernisation of the aircraft's electronic suite. Changes included the replacement of the 1950s ASV Mk 21 radar used by the Shackleton and Nimrod MR1 with the new EMI [[Searchwater radar]],{{refn|Equipped with the Searchwater radar, a Nimrod could offer an "[[Airborne early warning and control|AWACS]]-like" capability in the maritime environment.<ref>Jefford et al. 2005, p. 134.</ref>|group=N}} a new acoustic processor (GEC-Marconi AQS-901) capable of handling more modern sonobuoys, a new mission data recorder (Hanbush) and a new [[Electronic Support Measures]] (Yellow Gate) which included new pods on the wingtips.<ref name="Don World p95"/><ref name="face p9-0,12-4">''Air International'' July 1981, pp. 9–10, 12–14.</ref>

Provision for [[Aerial refuelling|in-flight refuelling]] was introduced during the [[Falklands War]] (as the ''MR2P''), as well as hardpoints to allow the Nimrod to carry the [[AIM-9 Sidewinder]] missile to counter enemy [[Argentine Air Force]] maritime surveillance aircraft.<ref>Brown 1987, p. 110.</ref> In preparation for operations in the [[Gulf War]] theatre, several MR2s were fitted with new communications and ECM equipment {{clarify|date=February 2020}} to deal with anticipated threats; at the time these modified aircraft were given the designation ''MR2P(GM) (Gulf Mod)''.<ref name="New role p53-4"/>

The Nimrod MR2 carried out three main roles: Anti-Submarine Warfare (ASW), Anti-Surface Unit Warfare (ASUW) and Search and Rescue (SAR). Its extended range enabled the crew to monitor maritime areas far to the north of Iceland and up to {{convert|4,000|km|nmi|order=flip}} out into the Western Atlantic. With Air-to-Air Refuelling (AAR), range and endurance was greatly extended. The crew consisted of two pilots and one flight engineer, two navigators (one tactical navigator and a routine navigator), one Air Electronics Officer (AEO), the sonobuoy sensor team of two Weapon System Operators (WSOp ACO) and four Weapon System Operators (WSOp EW) to manage passive and active electronic warfare systems.

Until 2010, the Nimrod MR2 was based at RAF Kinloss in Scotland ([[No. 120 Squadron RAF|120]], [[No. 201 Squadron RAF|201]] and [[No. 206 Squadron RAF|206]] Squadrons), and RAF St Mawgan in Cornwall ([[No. 42 Squadron RAF|42]] and [[No. 38 Squadron RAF|38(R)]] Squadrons). Following [[Options for Change]], 42 Squadron was disbanded and its number reassigned to 38(R) Squadron. The Nimrod MR2 aircraft was withdrawn on 31 March 2010, a year earlier than planned, for financial reasons.<ref>[http://www.mod.uk/DefenceInternet/DefenceNews/EquipmentAndLogistics/LastFlightOfTheNimrodMr2.htm "Last flight of the Nimrod MR2."] {{Webarchive|url=https://web.archive.org/web/20121004051634/http://www.mod.uk/DefenceInternet/DefenceNews/EquipmentAndLogistics/LastFlightOfTheNimrodMr2.htm |date=4 October 2012 }} ''Ministry of Defence'', 31 March 2010.</ref><ref>[http://www.raf-families-federation.org.uk/policies-news.asp?id=434 "Planning Round 10 is Going to be a Tough One."] {{Webarchive|url=https://web.archive.org/web/20110724052613/http://www.raf-families-federation.org.uk/policies-news.asp?id=434 |date=24 July 2011 }} ''RAF Families Federation'', 6 January 2010.</ref> The last official flight of a Nimrod MR2 took place on 26 May 2010, with XV229 flying from RAF Kinloss to [[Kent International Airport]] to be used as an evacuation training airframe at the nearby MOD Defence Fire Training and Development Centre.<ref>Wilson, Tom. [http://www.thisiskent.co.uk/Historic-plane-ends-career-Manston/story-11997519-detail/story.html "Historic plane ends its career at Manston."] {{webarchive|url=https://web.archive.org/web/20120402234152/http://www.thisiskent.co.uk/Historic-plane-ends-career-Manston/story-11997519-detail/story.html |date=2 April 2012 }} ''This is Kent,'' 8 June 2010. Retrieved 13 July 2011.</ref>

===AEW3===
{{multiple image
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 | image1 = Nimrod-XZ286-133.jpg
 | alt1 = Nimrod AEW3 in flight
 | image_caption1 = Nimrod AEW3 XZ286 at the 1980 [[Farnborough Air Show]]
 | image2 = Nimrod MRA4 1.jpg
 | alt2 = Nimrod MRA4 in flight
 | image_caption2 =Nimrod MRA4 ZJ518 during a test flight
}}
{{Main|British Aerospace Nimrod AEW3}}
In the mid-1970s a modified Nimrod was proposed for the [[Airborne Early Warning and Control|Airborne Early Warning]] (AEW) mission – again as a replacement for the [[Avro Lancaster|Lancaster]]-derived, piston-engined Shackleton AEW.2. Eleven existing Nimrod airframes were to be converted by [[British Aerospace]] to house the [[GEC Marconi]] radars in a bulbous nose and tail. The Nimrod AEW3 project was plagued by cost over-runs and problems with the [[GEC 4000 series|GEC 4080M]] computer used.<ref name="spyflight">[http://www.spyflight.co.uk/nim%20aew.htm "BAe Nimrod AEW 3."] {{Webarchive|url=https://web.archive.org/web/20120502141328/http://www.spyflight.co.uk/nim%20aew.htm |date=2 May 2012 }} ''Spyflight.'' Retrieved: 20 October 2010.</ref> Eventually, the MoD recognised that the cost of developing the radar system to achieve the required level of performance was prohibitive and the probability of success very uncertain, and in December 1986 the project was cancelled. The RAF eventually received seven [[Boeing E-3 Sentry]] aircraft instead.<ref name="spyflight"/>

===MRA4===
{{Main|BAE Systems Nimrod MRA4}}
The Nimrod MRA4 was intended to replace the capability provided by the MR2. It was essentially a new aircraft, with current-generation [[Rolls-Royce BR700|Rolls-Royce BR710]] turbofan engines, a new larger wing, and fully refurbished fuselage. The project was subject to delays, cost over-runs, and contract re-negotiations. The type had been originally intended to enter service in 2003 but was cancelled in 2010 as a result of the [[Strategic Defence and Security Review 2010|Strategic Defence and Security Review]], at which point it was £789&nbsp;million over-budget;<ref name=FT/> the development airframes were also scrapped.<ref>[https://www.bbc.co.uk/news/uk-england-12294766 "Scrapping RAF Nimrods 'perverse' say military chiefs."] ''BBC News,'' 27 January 2011.</ref> Some functions were allocated to other assets, with [[Lockheed C-130 Hercules|Hercules]] transport aircraft and E-3 Sentry Airborne Early Warning aircraft given some tasks, but the cancellation of the MRA4 resulted in a significant gap in long-range maritime patrol and search-and rescue capability.<ref>Hoyle, Craig. [https://www.flightglobal.com/news/articles/in-focus-uk-left-exposed-by-nimrod-cancellation-re-376998/ "IN FOCUS: UK left exposed by Nimrod cancellation, report says"]. ''Flightglobal'', 27 September 2012. Retrieved 21 May 2016.</ref><ref>{{cite web |url=https://publications.parliament.uk/pa/cm201213/cmselect/cmdfence/110/110.pdf |title=Future Maritime Surveillance |date=19 September 2012 |publisher=House of Commons Defence Select Committee |access-date=2020-05-28 }}.</ref>

In July 2016, the [[Ministry of Defence (United Kingdom)|Ministry of Defence]] announced the purchase of nine [[Boeing]] [[P-8 Poseidon|P-8A Poseidon]] aircraft for the RAF. The RAF declared the P-8 had reached [[initial operating capability]] (IOC) on 1 April 2020, by which time two of the planes had been delivered.<ref name=RAFIOC>{{cite web |title= RAF Declare Poseidon an Initial Operating Capability |url= https://www.raf.mod.uk/news/articles/raf-declare-poseidon-an-initial-operating-capability/ |date= 3 April 2020 |website= raf.mod |access-date=24 May 2020}}</ref> The nine aircraft will be based at [[RAF Lossiemouth]].<ref>{{Cite web |url=http://www.raf.mod.uk/news/archive/mod-seals-the-deal-on-nine-new-maritime-patrol-aircraft-to-keep-uk-safe-11072016 |title=MOD seals the deal on nine new Maritime Patrol Aircraft to keep UK safe |access-date=9 February 2017 |archive-url=https://web.archive.org/web/20170211075431/http://www.raf.mod.uk/news/archive/mod-seals-the-deal-on-nine-new-maritime-patrol-aircraft-to-keep-uk-safe-11072016 |archive-date=11 February 2017 |url-status=dead }}</ref>