The Sukhoi Su-27 is a twin-engine supermanoeuverable fighter aircraft designed by Sukhoi. It was intended as a direct competitor for the large United States fourth generation fighters, with 3,530-kilometre (1,910 nmi) range, heavy armament, sophisticated avionics and high manoeuvrability. The Su-27 most often flies air superiority missions, but is able to perform almost all combat operations. Complementing the smaller MiG-29, the Su-27's closest US counterpart is the F-15 Eagle. The Su-27 entered service with the Soviet Air Force in 1985.