Editing Avro Shackleton (section)

===Origins===
The [[Battle of the Atlantic]] was a crucial element of the [[Second World War]], in which Britain sought to protect its shipping from the German [[U-boat]] threat. The development of increasingly capable [[diesel-electric submarine]]s had been rapid, and in particular the [[Submarine snorkel|snorkel]] virtually eliminated the need for submarines to surface while on patrol. Aircraft that had once been highly effective submarine-killers had very quickly become incapable in the face of these advances.<ref name="jeff 67-68">Jefford et al. 2005, pp. 67–68.</ref> In addition, [[lend-lease]]d aircraft such as the [[Consolidated B-24 Liberator]] had been returned following the end of hostilities. Several [[Avro Lancaster]]s had undergone rapid conversion (designated Maritime Reconnaissance Mk 3 (MR3)) as a stopgap measure for maritime search and rescue and general reconnaissance duties;<ref>Jones 2002, pp. 22, 27.</ref> however, [[RAF Coastal Command]] had diminished to only a third of its size immediately after the Second World War.<ref name="jeff 68-69">Jefford et al. 2005, pp. 68–69.</ref>

In the emerging climate of the [[Cold War]], and the requirement to guard the North Atlantic from an anticipated rapid expansion of the [[Soviet Navy]]'s submarine force, a new aerial platform to perform the anti-submarine mission was required.<ref name="jeff 68-69"/><ref name = "Jones 43">Jones 2002, p. 43.</ref> Work had begun on the requirement for a new maritime patrol aircraft in 1944, at which point there had been an emphasis on long-range platforms for [[Far East]] operations. However, with the early end of the war in the Pacific, the requirement was refined considerably. In late 1945, the Air Staff had expressed interest in a conversion of the [[Avro Lincoln]] as a general reconnaissance and air/sea rescue aircraft, formalising their requirements for such an aircraft under [[list of Air Ministry specifications|Air Ministry specification]] R.5/46. Avro's Chief Designer [[Roy Chadwick]] initially led the effort to build an aircraft to this requirement, designated as the Avro ''Type 696''.<ref name = "flight 612"/><ref>Billings, Bill. [http://www.thegrowler.org.uk/shackleton_history.htm "The Shackleton Story."] {{webarchive |url=https://web.archive.org/web/20080705111648/http://www.thegrowler.org.uk/shackleton_history.htm |date=5 July 2008 }} ''The Shackleton Association''. Retrieved: 10 July 2008.</ref>

[[File:Shackleton-WR982-303.jpg|thumb|Interior of a Shackleton MR.3]]

The Type 696 was a significant development of the Lincoln. Elements of the [[Avro Tudor]] airliner were also reused in the design, both the Lincoln and the Tudor being derivatives of the successful wartime [[Avro Lancaster|Lancaster]] bomber.<ref>Buttler 2004,  p. 144.</ref><ref name = "Jones 30">Jones 2002, p. 30.</ref> Crucially, the new aircraft was to be capable of a {{convert|3000|nmi|mi km|adj=on||}} range while carrying up to {{convert|6000|lb||||}} of weapons and equipment. In addition to featuring a large amount of electronic equipment, the Type 696 provided a much-improved crew environment compared to other aircraft types, to allow the crew to be more effective during the anticipated lengthy mission times.<ref name="jeff 70-71">Jefford et al. 2005, pp. 70–71.</ref><ref name = "flight 611">''Flight'' 18 May 1950, p. 611.</ref> During development the Type 696 was provisionally referred to as the ''Lincoln ASR.3'' before the official name 'Shackleton' was selected.

The first test flight of the prototype Shackleton GR.1, [[United Kingdom military aircraft serials|serial]] ''VW135'', was made on 9 March 1949 from the manufacturer's airfield at [[Woodford, Cheshire]] in the hands of Avro's Chief Test Pilot J.H. "Jimmy" Orrell.<ref>Harlin and Jenks 1973, p. 164.</ref> The GR.1 was later redesignated "Maritime Reconnaissance Mark I" (MR 1). The prototype differed from subsequent production Shackletons in a number of areas, featuring several [[Gun_turret#Aircraft|gun turrets]] and was equipped for air-to-air refuelling using the [[Aerial refueling#Grappled-line looped-hose|looped-line method]]. These did not feature on production aircraft due to performance difficulties or being judged ineffective.<ref>Jones 2002, pp. 34, 36–37, 39.</ref> However, the performance of the prototype had been such that in addition to the go-ahead for the MR1's production, a specification for an improved variant was issued in December 1949, before the first production Shackleton had even flown.<ref name="jeff 71-74">Jefford et al. 2005, pp. 71–74.</ref> By 1951, the MR1 had become officially considered as an interim type due to several shortcomings.<ref name = "Jones 67">Jones 2002, p. 67.</ref>