The Su-27KUB is a twin-seat derivative of the single-seat Su-27K deck fighter first flown in 1987 and officially accepted in service with the Russian Navy in August 1998. Designation of project is T10KUB. A prototype T10KUB-1 (no. 21) was built in Komsomolsk-on-Amur in 1995-1998 and assembled in Moscow. First flight of T10KUB: 29th April 1999 by V.G. Pugachov and S.N. Melnikov. Both the Su-27K and Su-27KUB feature Sukhoi’s characteristic “integral triplane layout”, a combination of canards, main wing and stabiliser. The main external difference is that the KUB has a forward section resembling that of the Su-34 land-based naval strike aircraft. The latter had its public debut at the 1995 Paris Air Show. Apart from the two naval airplanes, a similar nose section is used on the Su-34 interdiction aircraft intended to form the backbone of Russian Front-line Aviation in the next century.
Although neither the Russian Navy nor Sukhoi has revealed the roles that the Su-27KUB would fulfill, it is known that the new aircraft would supplement Su-27Ks, and not supersede them.
The KUB suffix means “Korabelny, Uchebno-Boyevoi”, or “Ship-borne, Training, Combat” in English. In addition to the primary combat roles, the KUB will seemingly be used for training purposes, most notably practising operations from the deck of a carrier. Also, the KUB might be used for restoration of flying skills of line Navy pilots. In this role the Su-27KUB would supplement the Su-25UTG straight-wing twin-jet, a navalized version of the Su-25 attack aircraft. There is no certainty about the Su-27KUB’s combat functions as of yet. Sukhoi has not revealed information on the avionics suite installed on the airplane. It might be that the KUB would carry the Sea Snake aiming complex and other systems developed for the Su-34, which is a dedicated strike aircraft intended to act against sea-going targets and submarines.
The Sea Snake complex built around the Argon central computer, has a coherent radar able to detect a ship at a range of 150-200 km. Also, the complex has infrared, electro-optical, acoustic, magnetic and other sensors.
In 1999 the Sukhoi Su-27KUB two-seat carrier fighter/trainer has begun arrested landing trials at Saki in the Crimea, only five months after its first flight. The aircraft is using the NITKA (Nauchno-Issledovatyelski trenirovochny kompleks aviatsii /Aviation scientific-research and training complex) facility at the Ukrainian-owned former Soviet Naval Air Base while the Russian Navy’s sole carrier, the Admiral Kuznetsov, is undergoing repair and refurbishment at Murmansk. Flight tests from the carrier are planned for later in the year on completion of that work. The NITKA provides a representation of Kuznetsov’s deck, with ski-jump and four-wire arresting gear. Although intended for carrier conversion training of pilots, the large side-by-side cockpit of the Su-27KUB makes it an excellent platform for more specialized tasks, amongst which the Russian Navy plans anti-shipping strike, land attack, reconnaissance and electronic warfare.
The Su-27KUB is equipped with the standard Al-31F engines but in the future they will be replaced with the Al-31FP engines with thrust vector control (TVC). The onboard radar is an N-014 developed at the Fazotron institute.