The Sukhoi Su-35 (-35; NATO reporting name: Flanker-E) is the designation for two improved derivatives of the Su-27 air-defence fighter. They are single-seat, twin-engine, supermaneuverable aircraft, designed by the Sukhoi Design Bureau and built by Sukhoi. The type was originally developed by the Soviet Union from the Su-27 and was known as the Su-27M. It incorporated canards and a multi-function radar giving it multi-role capabilities. The first prototype made its maiden flight in June 1988. Following the dissolution of the Soviet Union Sukhoi re-designated it as the Su-35 to attract export orders. Fourteen aircraft were produced and used for tests and demonstrations; one example had thrust-vectoring engines and was in turn redesignated the Su-37. A sole Su-35UB two-seat trainer was also built in the late 1990s that resembled the Su-30MK family. In 2003, Sukhoi embarked on a second modernization of the Su-27 to serve as an interim aircraft awaiting the development of the Sukhoi PAK FA (Su-57) program. Also known as the Su-35, this version has a redesigned cockpit and weapons-control system and features thrust-vectoring engines in place of the canards. The type made its first flight in February 2008. Although it was designed for export, the Russian Air Force became the launch customer in 2009, with the production version designated Su-35S. China's People's Liberation Army Air Force has also placed orders. Design and development Upgraded Su-27 The first aircraft design to receive the Su-35 designation had its origins in the early 1980s, at a time when the Su-27 was being introduced into service with the Soviet Armed Forces. The definitive production version of the Su-27, which had the factory code of T-10S, started mass ("serial") production with the Komsomolsk-on-Amur Aircraft Production Association (KnAAPO) in 1983. The following year, this Su-27 version reached initial operational readiness with the Soviet Air Defence Forces. Having begun work on an upgraded Su-27 variant in 1982, the Sukhoi Design Bureau was instructed in December 1983 by the Soviet Council of Ministers to use the Su-27 as the basis for the development of the Su-27M (T-10M). Nikolay Nikitin would lead the design effort throughout much of the project's existence, under the oversight of General Director Mikhail Simonov, who had been the chief designer of the Su-27 along with Mikhail Pogosyan. While sharing broadly the blended wing-body design of the Su-27, the Su-27M is visibly distinguished from the basic version by the addition of canards, which