The navalised Su-27K for Korablny' was developed for the Project 1143.5 55,000 tonne class aircraft carrier, of which four were to have been built. The Su-27K is the Russian equivalent to the US Navy F-14 series, but also important as it was the prototype for design features which migrated to a wide range of other Flanker variants and derivatives.

The Su-27K had folding wings and stabilators, strengthened undercarriage with twin nosewheels, upgraded hydraulics, a tailhook, enlarged flaperons, a modified ejection seat angle, folding outer wings and stabs, upgraded FBW, modified LERX (Leading Edge Root Extensions) with canards, enlarged leading edge slats and a deployable aerial refuelling probe. The refuelling probe modification included a pair of deployable floodlights in the nose, used to illuminate the tanker aircraft, here intended to be either an Il-78 Midas or another Su-27 buddy tanker carrying a centreline UPAZ hose-drogue pod. The probe permits a fuel transfer rate into the fighter of up to 4,000 lb/min. Another notable Su-27K feature which migrated to later Flanker variants was the right offset IR Search and Track housing, this improving the pilot's downward view over the aircraft's nose. Production Su-27Ks operated by the Russian Navy are often designated the Su-33. Perhaps the most important feature of the Su-27K/Su-33 are the enlarged LERX/canards which increase the available body lift of the aircraft, and the centre of pressure forward thus enhancing achievable pitch rates. The Su-27 series shares with the F-14 series a large body lift capacity resulting from the wide fuselage tunnel - as a result the aircraft's effective wing loading is much lower than that of aircraft with different configurations. This is reflected in superb high alpha handling and sustained turn rates. The enlarged LERX/canards migrated to a range of other Flanker variants, including the Su-35, Su-37 and production Su-30MKI.

Experience from initial Su-27K flight testing and trials indicated that major issues would arise with training pilots for carrier recoveries. Without the large range of aircraft types, and specialised carrier trainers operated by the US Navy, the Soviet AV-MF needed an aircraft which was identical in handling to the basic Su-27K but dual seated, without the forward visibility impediments of the existing tandem configuration Su-27UB.

Design of the dual navalised combat trainer derivative began in 1989, the aim being to produce an airframe suitable for a range of other carrier based roles such as reconnaissance, aerial refuelling, maritime strike and support jamming - niches in the US Navy now being filled by F/A-18E/F derivatives.

The new Su-27KUB (Korabl'niy Uchebno-Boyeviy - Shipboard Trainer-Combat) included a radically revised forward fuselage and a range of incremental aerodynamic changes. The latter are cited as enlargement of the canards, stabilisers, fins and rudders. The wing fold position was moved further outboard.

The new side-by-side cockpit involved a major resculpting of the forward fuselage, with crew access via a nosewheel well deployable ladder. The crew sit on upward firing ejection seats under jettisonable canopy panels. The circular cross section of the nose was retained, but the baseline NIIP N-001 multimode radar was to be replaced by a Phazotron Zhuk derivative. The OEPS/OLS-27 IRST housing was located on the centreline of the cockpit.

The prototype Su-27KUB first flew in April 1999, but no significant production orders have materialised due to the collapse of Russian carrier aviation funding post 1991. Production aircraft, designated as Su-33UB, would be built by KNAAPO at Komsomolsk Na Amure.

A demonstration Su-33UB aircraft has been flown at a Russian airshow, equipped with thrust vectoring Saturn Al-31FU engines. A TVC capability would be useful for ski jump launches, reduced approach and trap speeds, and improved turning performance, compromised to some extent by the heavier forward fuselage against baseline Flanker variants.