Air Force, 70 went to the Royal Indian Air Force and 30 of its reconnaissance variant went to the Royal Thai Air Force. Mk XV and Mk XVII The mark numbers XV and XVII (15 and 17) were reserved for the naval version, the Seafire, in an effort to reconcile the Spitfire numbering scheme with that of the Seafire. Mk XVIII (Mk 18) (type 394) The Mk 18 was a refinement of the Mk XIV. It was identical in most respects including engine (the Griffon 65) and cockpit enhancements, but it carried extra fuel and had a revised, stronger wing structure. Its handling was also nearly identical and so it was not put through any performance tests. Like the Mk XIV there were fighter and fighter reconnaissance variants built. The Mk 18 missed the war. It was built up until early 1946 but it was not until January 1947, that an RAF squadron, 60 Squadron which operated from RAF Seletar, Singapore, was re-equipped with the variant. Later, other squadrons in the Far East and Middle East would receive them. Some 300 F Mk 18s and FR Mk 18s were built, before production ended in early 1946. The Mk 18s saw little action apart from some involvement against guerrillas in the Malayan Emergency. The Royal Indian Air Force purchased 20 ex-RAF Mk 18s in 1947. Mk XIX (Mk 19) (types 389 and 390) The Mk XIX was the last and most successful photographic reconnaissance variant of the Spitfire. It combined features of the Mk XI with the Griffon engine of the Mk XIV. After the first 25 (type 389s) were produced, later aircraft were also fitted with the pressurised cabin of the Mk X and the fuel capacity was increased to 256 gallons, three-and-a-half times that of the original Spitfire This version was the type 390. The first Mk XIXs entered service in May 1944, and by the end of the war the type had virtually replaced the earlier Mk XI. A total of 225 were built with production ceasing in early 1946, but they were used in front line RAF service until April 1954. In 1951, Hainan Island (People's Republic of China) was targeted at the behest of US Naval Intelligence for RAF overflights, using Spitfire PR Mk 19s based at Kai Tak Airport in Hong Kong. The last operational sortie by a Mk 19 was in 1963 when one