Sukhoi S - 54 The Sukhoi S - 54 is a series of three closely related aircraft proposals ; the S - 54 trainer aircraft , S - 55 light fighter designed for export , and the S - 56 carrier - capable light fighter . All members of the family resemble the Sukhoi Su - 27 in general form , or the Sukhoi Su - 33 more closely , but built around a single example of the Saturn AL - 31 engine instead of two , and scaled down accordingly to a smaller layout . The design was offered to several potential customers , including South Africa and India , but was turned down . Development is apparently on hold , awaiting a launch customer . Design and development . Genesis . The project traces its origins to a 1990 requirement to replace the aging Aero L - 39 jet trainers , which were reaching the end of their service lives . The original Aero L - 29 had originally been selected as a Warsaw Pact - wide trainer in 1961 , after beating out the Yak - 30 and PZL TS - 11 Iskra . It started to be replaced in 1974 by the greatly updated L - 39 , powered by the new Ivchenko AI - 25 engine . By 1990 the Soviet Air Force had about 1 , 000 L - 39s on force , when the new Czech Republic stated they would no longer be supplying spares . The Soviet Air Force ' s commander - in - chief , Air Marshal Yefimov , issued a statement on the issue on 20 April 1990 . On 25 June 1990 the first official RFP document was issued for the Uchebno - Trenirovochnyi Samolyot ( UTS ) program . Four companies responded with designs , the Mikoyan MiG - AT , Yakovlev Yak - 130 ( then known as the Yak - UTS ) , the Myasischev M - 200 and the S - 54 . Most of these designs were typical trainers ; they were built to be docile in handling , low cost in operation , and were essentially all - new in design . Sukhoi decided to take a different approach , and develop a true high - performance design closer to a fighter than a trainer . Advances in aerodynamics and flight controls allowed even the most advanced fighters have docile handling suitable for transition training , while at the same time the older generation aircraft had handling so different than modern aircraft to make them of limited utility . Given their extensive experience with upgraded versions of the original Su - 27 , Sukhoi chose to use much of this design in the new trainer . Versions with one AL - 31 or two smaller engines were studied , with the single - engine version favoured throughout . The design that emerged appeared to be a Su - 33 with a fuselage plug removed behind the cockpit , giving it a cross - section similar to other advanced trainers of the era . The first design study , shown publicly not long afterwards , was upgraded and improved during 1992 . A new version , with airframe enlarged by approximately 25 per cent , was revealed at 1996 Farnborough Air Show . The Yak - 130 eventually won the UTS contract , and Sukhoi started looking for other markets . S - 55 and S - 56 . Sukhoi then modified the design to allow it to mount the same radar as the Su - 27 , the Phazotron Sokol . Shown in June 1997 , the S - 55 was a lighter , shorter - range fighter that complimented the Su - 27 in the same way the F - 16 compliments the F - 15 . Designed as a low - cost fighter , primarily for export , the S - 55 was nevertheless a very advanced design compared to similar fighters that were " up - converted " from trainers . Sukhoi also produced the S - 56 , essentially an S - 55 adapted for carrier use . The design was deliberately tailored for the " Admiral Kuznetsov " , and was designed to fit into a 10 by 3 by 3 meter space , making it one of the most compact naval fighters ever designed . The small size , especially vertically , opened the possibility of adding another internal deck between the two existing aircraft decks in the " Kuznetsov " , increasing the total number of fighters that could be carried by two to three times . The S - 56 was also offered to the Indian Navy in 1999 , but was not purchased .