Editing Invincible-class aircraft carrier (section)

==Development==
The ''Invincible'' class has its origins in a sketch design for a 6,000-[[long ton|ton]], guided-missile armed, helicopter carrying escort cruiser intended as a complement to the much larger [[CVA-01|CVA-01-class]] fleet aircraft carrier.<ref name="Grove">{{cite book|title=Vanguard to Trident; British Naval Policy since World War II |first=Eric J. |last=Grove |publisher=The Bodley Head |date=1987 |isbn=0-370-31021-7}}</ref> The cancellation of CVA-01 in 1966 meant that the smaller cruiser would now have to provide the [[anti-submarine warfare]] (ASW) taskforce with [[Command and control (military)|command and control]] facilities. Two new designs were prepared for this requirement;<ref name="Grove"/> a 12,500-ton cruiser with missiles forward, six Westland Sea King helicopters and a flight deck aft, somewhat similar to {{ship|Italian cruiser|Vittorio Veneto|550|2}} of the [[Marina Militare|Italian Navy]] and a larger 17,500-ton vessel with a "through-deck", nine Sea Kings and missiles right forward. By 1970, the "through-deck" design had advanced into a Naval Staff Requirement for an 18,750-ton Through-Deck Command Cruiser (TDCC).<ref name="Grove"/>

In February 1963, the [[Hawker P.1127]] VTOL (vertical take-off and landing) aircraft had landed and taken-off from the carrier {{HMS|Ark Royal|R09|2}} and the subsequent [[Hawker P.1127#Kestrel FGA.1|Hawker-Siddeley Kestrel]] had undergone trials from the "Commando carrier" (an aircraft carrier operating helicopters) {{HMS|Bulwark|R08|6}}. It was therefore perfectly possible that the new "cruisers" could be used to operate VTOL aircraft.<ref>[https://api.parliament.uk/historic-hansard/written-answers/1969/mar/26/cruisers-vstol-aircraft Hansard HC Deb 26 March 1969 vol 780 c303W] ''Cruisers (V/STOL Aircraft)''<br>"[[Patrick Wall|''Mr. Wall'']] asked the Secretary of State for Defence whether the new cruisers will operate vertical/short take-off and landing aircraft; and when it is expected the first will be ordered.<br>[[John Morris, Baron Morris of Aberavon|''Mr. John Morris'']] No decision has yet been taken whether vertical and short take-off and landing aircraft should be operated at sea. It is too early to say when the first of the new cruisers will be ordered."</ref> The new ships were called [[aircraft cruiser|"through-deck cruisers"]] and not "aircraft carrier". This was in part because CVA-01's cancellation was so recent, but also because the ships were intended to serve in traditional cruiser roles of [[Command, Control, Communications and Intelligence|C<sup>3</sup>I]] and anti-submarine warfare, and were constructed like cruisers.<ref name="james19991">{{cite journal | url=http://www.naval-review.co.uk/issues/1999-1.pdf | title=Carrier 2000: A Consideration of Naval Aviation in the Millennium – I | author=James, D. R. | journal=The Naval Review | date=January 1999 | volume=87 | issue=1 | pages=3–8 | access-date=12 December 2011 | archive-date=26 April 2012 | archive-url=https://web.archive.org/web/20120426045355/http://www.naval-review.co.uk/issues/1999-1.pdf | url-status=dead }}</ref> The "aircraft carrier" name did not officially appear in association with the ships until the 1980 [[Defence Estimates]] referred to the ''Invincible''s as such.<ref>{{cite book|last=Benbow |first=Tim |title=Seapower at the Millennium |editor=Geoffrey Till |publisher=Royal Navy Museum Publications and Sutton Publishing |location=Thrupp, Gloucestershire|year=2001 |chapter=British Naval Aviation: Limited Global Power Projection |isbn=0-7509-2458-6 |pages=61, 341}}</ref>

Economic problems in the UK in the early 1970s delayed progress on the new ships, but the design continued to evolve. The order for the first ship was given to [[Vickers Shipbuilding and Engineering|Vickers (Shipbuilding)]] on 17 April 1973.<ref name="Moore">''Warships of the Royal Navy'', Capt. John E. Moore RN, Jane's Publishing, 1981, {{ISBN|0-7106-0105-0}}</ref> By now, the design was for a 19,000-ton "CAH"<ref name="Grove"/> (helicopter carrying heavy cruiser, styled after the [[US Navy hull classification symbol]]s) with up to fourteen aircraft and a [[Sea Dart missile]] launcher on the bows.

The government decided that the carrier needed fixed-wing aircraft to defend against Soviet reconnaissance aircraft.{{r|james19991}} In May 1975, it authorised the maritime version of the [[Hawker Siddeley Harrier]],<ref name="Grove"/><ref name="Moore"/> which was successfully developed into the [[BAE Sea Harrier|Sea Harrier]]. This meant that the design was reworked again to include a small complement of these [[VTOL]] aircraft. The comparatively short {{convert|170|m|adj=on}} [[flight deck]] made even [[STOVL]] rolling take-offs marginal for launching fully laden Harriers. The development of the [[Ski-jump (aviation)|ski-jump]] made it possible to launch in all conditions by propelling the aircraft upwards at the end of its take-off roll. ''Invincible'' and ''Illustrious'' were equipped with 7° ski-jumps, and ''Ark Royal'' carried a 12° ski-jump.<ref name="hobbs2015">{{cite book |last1=Hobbs |first1=David |title=The British Carrier Strike Fleet: After 1945. |date=2015 |publisher=Seaforth Publishing |isbn=9781612519999 |pages=469–472}}</ref> The class also had, since 1976,<ref name="Grove"/> a secondary role as a helicopter carrier, or [[Landing Platform, Helicopter|LPH]], in the reinforcement of NATO's Northern flank in Norway. In 1998, {{HMS|Ocean|L12|6}}, with a hull form based on that of the ''Invincible'' class, was commissioned specifically for this role.

[[File:HMS Invincible 1991 DN-ST-92-01125s.jpg|thumb|left|HMS ''Invincible'' in 1991]]
After the 1982 [[Falklands War]], [[CIWS]] guns were added to the design. ''Illustrious'' had them fitted at the last minute before commissioning, ''Ark Royal'' had them added as a normal part of the building process, and ''Invincible'' had them fitted during her first overhaul after the Falklands. Initially, ''Invincible'' and ''Illustrious'' were fitted with two [[Phalanx CIWS|Vulcan Phalanx]] units; these were replaced with three [[Goalkeeper CIWS|Goalkeeper]] systems. ''Ark Royal'' retained the three [[Phalanx CIWS]] systems she was fitted with when built (she could be easily distinguished from her sisters by the Phalanx's distinctive white "[[R2-D2]]" radome). Electronic countermeasures were provided by a Thales jamming system and ECM system. [[Seagnat]] launchers were provided for chaff or flare decoys. As part of upgrades during the mid-1990s, all three ships had the Sea Dart removed, with the forecastle filled in to increase the size of the flight deck.

===Foreign interest===
In the mid-1970s, the [[Shah Mohammad Reza Pahlavi|Shah]] of [[Pahlavi dynasty|Iran]] expressed interest in acquiring three ''Invincible''-class ships and a fleet of twenty-five [[BAE Sea Harrier|Sea Harriers]] to provide fleet defence. When the [[Iranian Navy]] could not commit to providing sufficient personnel for manning the vessels, the ship order was cancelled in 1976.<ref name=Iran>[http://www.secretprojects.co.uk/forum/index.php/topic,11062.0.html Secret Projects, 13 September 2010]</ref> A later proposal to buy four "Harrier-type" vessels was also discarded, as were later negotiations to buy the Sea Harrier.

The [[1981 Defence White Paper]] and its planned reduction in the size of the carrier fleet saw ''Invincible'' marked as surplus to requirements, and the ship was offered for sale to the [[Royal Australian Navy]] in July 1981 as a replacement for the ageing aircraft carrier {{HMAS|Melbourne|R21|6}}.<ref>{{cite book |last=Wright |first=Anthony |title=Australian Carrier Decisions: the acquisition of HMA Ships Albatross, Sydney and Melbourne |orig-year=1978 |series=Papers in Australian Maritime Affairs (No. 4) |date=June 1998 |publisher=Sea Power Centre |location=Canberra |isbn=0-642-29503-4 |oclc=39641731 |issn=1327-5658 |page=167}}</ref> The class had previously been considered and discarded as a potential replacement for the Australian ship, but the low [[Pound sterling|£]]175&nbsp;million ([[Australian dollar|A$]]285&nbsp;million) offer price and the already-constructed state of the vessel prompted the Australian government to announce in February 1982 their intention to accept the British offer.<ref name=Stevens227>{{cite book |author=Stevens, David |author2=Sears, Jason |author3=Goldrick, James |author4=Cooper, Alastair |author5=Jones, Peter |author6= Spurling, Kathryn  |editor=Stevens, David |title=The Royal Australian Navy |series=The Australian Centenary History of Defence (vol III) |year=2001 |publisher=[[Oxford University Press]] |location=South Melbourne, VIC |isbn=0-19-554116-2 |oclc=50418095 |page=227}}</ref> In Australian service, the ship would have been named HMAS ''Australia'', and would operate as a helicopter carrier until a later decision on the acquisition of Sea Harriers was made.<ref name=Hobbs9>{{cite journal |last=Hobbs |first=Commander David |date=October 2007 |title=HMAS ''Melbourne'' (II) – 25 Years On |journal=The Navy |volume=69 |issue=4 |page=9 |issn=1322-6231}}</ref> ''Invincible''{{'}}s service during the Falklands War showed that the White Paper's suggested reductions were flawed and both nations withdrew from the deal in July 1982.<ref name=Stevens227/>