Fairchild Republic and Northrop each built two prototypes for evaluation under the US Air Force's A-X programme, initiated in 1967, for a close support aircraft. The first Fairchild Republic prototype (71-1369), designated YA-10A, flew for the first time 10 May 1972. It was announced 18 January 1973 that Fairchild was the winner of the competitive evaluation of the prototypes, and received a contract for six A-10A DT and E aircraft, the first of which flew 15 February 1975. The first flight by a production A-10A Thunderbolt II (75-00258) was made 21 October 1975. Purchase of a total of 739 aircraft was planned (including the six DT and E aircraft); but funding was terminated in 1983 after a total of 713 production A-10s had been ordered. Delivery was completed 20 March 1984. There were still 327 aircraft in service with the USAF, USAF Reserve and ANG in early 1994. The Thunderbolt II was used during the Gulf War of 1991.