The A330 MRTT (Multi-Role Tanker Transport) is a conversion of the A330-200 civilian airliner that can function as both a transport and a tanker. It is the second such conversion of an Airbus airliner, following the A310 MRTT that was adopted by the German Luftwaffe (among others). The conversion was prompted due to the RAF's need to replace its aging TriStar and VC10 tankers as part of the Future Strategic Tanker Aircraft (FSTA) program. The main difference with the airliner version is the provision for wing refueling pods of various types depending on the operator. However, aside from its tanker role, it can also be adapted as a troop transport, Medevac aircraft (with up to 130 stretchers), and well as a cargo aircraft loaded through a cargo door. Aside from the RAF, the A330 MRTT has also been adopted or ordered by Australia, France, Saudi Arabia, Singapore and the UAE. The A330 MRTT had also won a competition for a successor to the US KC-135 (the KC-X program); however, the competition has relaunched due to an appeal by Boeing which subsequently went on to win it despite complaints that the bid was biased in its favor.
First flight of a converted A330-200 took place on 15 June 2007, and it entered service in Australia initially where it is known as the KC-30A and is equipped with wing refueling pods and an Aerial Refuelling Boom System (ARBS). In RAF service it is known as the Voyager KC.2 and KC.3, which differ only on account on their pod configurations, the latter which has a Fuselage Refueling Unit (FRU) for use with larger aircraft. A version designed for US service in partnership with Northrop Grumman was known as the KC-30 for the initial (winning) bid. This was later redesignated as the KC-45 for the second and definitive bid which was lost to Boeing.