820 Naval Air Squadron 820 Naval Air Squadron is a Royal Navy Fleet Air Arm carrier based squadron formed in April 1933 with the transferral of the Fairey III aircraft from 405 Flight Royal Air Force to the Fleet Air Arm . It has operated , with a number of brief gaps , up to the present day and continues in service , flying the Merlin HM . Mk . 1 out of RNAS Culdrose . History . Second World War . The squadron ' s first assignment on its formation was to provide spotter - reconnaissance duties for the aircraft carrier HMS " Courageous " . They were later re - equipped with Fairey Seal s and Blackburn Shark s , eventually receiving Fairey Swordfish in autumn 1937 . The squadron was reassigned in November the following year to the new aircraft carrier , HMS " Ark Royal " . The squadron operated from here for the next three years , initially on anti - submarine duties , but later as surface search and torpedo - attack aircraft . The squadron went with " Ark Royal " to the Atlantic , and by April 1940 they were supporting allied operations during the Norwegian campaign , where they bombed Vaernes airfield . After the withdrawal from Norway , " Ark Royal " and the squadron moved to the Mediterranean in June . Aircraft from 820 squadron were involved in attacking the French fleet at Mers - el - Kébir , and later the Battle of Dakar , as well as attacks at Cagliari . They were also active during the Battle of Cape Spartivento , as well as covering convoys to Malta . 820 Squadron ' s next major engagement was the hunt for the German battleship " Bismarck " . Aircraft from the Squadron were able to disable the " Bismarck " ’ s steering gear with a torpedo hit , allowing the " Bismarck " to be engaged and sunk . In June 1941 the squadron left " Ark Royal " , and in November that year returned to Iceland aboard HMS " Victorious " . The Swordfish were then replaced with Fairey Albacore s . 820 Squadron then embarked aboard HMS " Formidable " in February 1942 , and sailed with " Formidable " to serve in the Indian Ocean . The squadron was then active in the Battle of Madagascar , followed by Operation Torch , the Allied landings in North Africa . During these operations , aircraft from the squadron sank the German U - boat " U - 331 " , which had earlier sunk the battleship HMS " Barham " . " Formidable " and the squadron remained in the Mediterranean to provide support for the Allied landings at Sicily and Salerno . The squadron then returned to the UK in November 1943 and disbanded at RNAS Donibristle . The squadron was quickly reformed however , and equipped with 12 Fairey Barracuda s was initially based at RNAS Lee - on - Solent as a torpedo bomber / reconnaissance squadron . They were assigned to HMS " Indefatigable " in June 1944 and saw action as part of Operation Mascot on 17 July and Operations Goodwood in August , the attempts to sink the German battleship " Tirpitz " in Kaa Fjord , Alta , Norway . The operations failed to cause significant damage to the " Tirpitz " . The squadron was re - equipped with 21 Grumman Avenger s in September 1944 and sailed with " Indefatigable " to the Far East in November . They sailed to Ceylon where 820 squadron joined No 2 Strike Wing , which also consisted of 849 Squadron . The Wing attacked the oil refineries at Palembang , Sumatra in January 1945 as part of Operation Meridian , following this up with later strikes on the Sakashima Gunto islands . As the war in the Pacific moved closer to Japan 820 Squadron was assigned to the 7th Carrier Air Group , and carried out a number of raids on Tokyo prior to VJ - Day . After the end of the war , " Indefatigable " remained in the Pacific for some time , finally returning to the UK in March 1946 . 820 Squadron was then disbanded again . Post war . The squadron was re - formed five years later in July 1951 , this time flying the Fairey Firefly . The squadron was embarked alternately aboard the carriers HMS " Indomitable " and HMS " Theseus " during 1952 and 1953 , spending most of its time on exercises in the Mediterranean . The squadron operated the Grumman Avenger and then the Fairey Gannet during 1954 and 1956 , aboard HMS " Centaur " and HMS " Bulwark " , before the decision was made to convert 820 Squadron as a helicopter squadron . 820 disbanded on 2 December 1957 but were immediately re - formed the same day at HMS " Vernon " , equipped with the Westland Whirlwind MK VII . They were assigned to HMS " Hermes " in May 1958 as an anti - submarine and commando support force , remaining aboard " Hermes " until October 1960 , when the squadron was again disbanded . The squadron was re - formed in 1964 , and equipped with the Westland Wessex MK1 , with which they served as anti - submarine squadron aboard HMS " Eagle " . They were upgraded to the MK3 in 1969 , when they were transferred to the " Tiger " class helicopter cruiser HMS " Blake " . They remained aboard " Blake " until her disposal in 1979 , having been upgraded with the Westland Sea King HS . Mk . 1 in December 1972 , followed by the HS . Mk . 2 version and then the HS . Mk . 5 in December 1980 . The squadron was then assigned to HMS " Invincible " in April 1982 for the Falklands War . During the conflict the squadron flew over 4700 hours , with " Invincible " spending 166 days continuously at sea , setting a world record for continuous carrier operations . The squadron transferred to HMS " Ark Royal " in late 1985 . They were re - equipped in February 1990 with the Sea King MK5 , and in January 1993 were dispatched aboard RFA " Olwen " and RFA " Fort Grange " to support the British forces in Bosnia as part of Operation Grapple . There the squadron was used to ferry men and supplies . 820 Squadron returned to Bosnia in 1994 , this time aboard HMS " Ark Royal " . With the later decommissioning of " Ark Royal " , the squadron joined HMS " Illustrious " and by 1996 was in the eastern Atlantic , followed by a round the world deployment in 1997 . With " Illustrious " in refit from 1998 , 820 Squadron operated out of RNAS Culdrose on anti - submarine training exercises , followed with periods embarked on ships of the Royal Fleet Auxiliary . They rejoined " Illustrious " in 1999 and participated in relief operations in Mozambique , aboard RFA " Fort George " , and for Operation Palliser in Sierra Leone . Further training periods followed , as well as a Search and Rescue effort in October 2004 to aid the stricken Canadian submarine HMCS " Chicoutimi " , which had been disabled after suffering a fire and flooding off the west coast of Ireland . Present day . The squadron continues to carry out exercises aboard Royal Navy and Royal Fleet Auxiliary vessels , as well as participating in military operations . It is based at RNAS Culdrose and operates the Merlin HM . Mk . 1 . Training is performed by 824 NAS and front line duties are shared with 814 NAS .