IN-DEPTH: Russia's declining Su-27/30 Flanker fleet

The Sukhoi Su-27/30 fleet in Russia is now declining in numbers; even if it is set to continue more or less unchanged in the foreseeable future, as Alexander Mladenov explains.

Dubbed by NATO as the Flanker-B/C, the first-generation Su-27s are becoming an increasingly rare sight in Russian service, having been promptly replaced by the Su-35S in most front-line regiments from 2014. The active fleet of both ‘legacy’ and upgraded or newly-built single and two-seat Flankers, operated by the Russian Aerospace Forces (VKS) and the Russian Naval Aviation (AVMF), currently numbers 140 to 150 aircraft; this figure includes about 70 non-upgraded examples – some 35 single-seaters and no fewer than 35 twin-seaters. Between 2015 and 2021, no fewer than 30 of the first-generation Flankers in Russia were cycled through extensive general overhauls. This provided 500 more flight hours and eight years of service, while others underwent life-extending deep airframe inspections at a lower cost. The service life is currently set at 35 years.

Two principal factors led to the short lived service of most first-generation Flankers in Russian service. Initially fielded in an accelerated manner during the second half of the 1980s, deliveries continued at a much slower pace until 1996. The first is related to the possible reluctance of the Russian aerospace industry and fighter maker Sukhoi to deal with a fleet-wide mid-life upgrade and life extension program, offering hefty prices and long lead times for such complex activities. Additionally, instead of upgrading the existing fleet, the industry has kept its aircraft plants running, supplying the Russian military with newly-built fighters of the advanced Flanker multi-role derivatives, such as the Su-30SM and Su-35S. The second factor contributing to the rapidly shrinking fleet is related to poor standards of long-term storage of hundreds of grounded Flankers from the fighter regiments of the Russian air arm which were disbanded in the 2000s.

This resulted in significant airframe corrosion, while most of these aircraft were also rapidly cannibalized for their useful parts and equipment. In addition, a significant number of aircraft, mostly two-seaters, were grounded due to fuselage cracking and deformation issues; caused by intense and repetitive high-G maneuvering in training flights when serving with both the front-line units and in the ‘Russikie Vityazi’ (Russian Knights) display team, who flew the type in a rather aggressive manner until 2016. This, in turn, has led to a sharp increase in prices for structural overhauls and modifications necessary to restore airworthiness and life extensions needed to render the otherwise low hour but aging Flankers useful for 10 to 15 more years. Consequently, a significant number of aircraft, placed in long-term storage in the 2000s due to expired time between overhauls or structural problems, were scrapped or re-rolled as gate guards and ground instructional airframes.

Combining these adverse factors could explain why fewer than 20% of the Russian Su-27 fleet - single-seaters only - were eventually cycled through the SM/SM3 upgrade and life-extension effort.

Stripped from an air-to-surface capability, the non-upgraded single seat fleet comprises mainly the Su-27P (T10P) version, serving together with a small number of the original Su-27S (T10S). The T10P derivative was rolled off the production line for the first time in 1989. Built in the mid and late 1980s, a significant number of single and two-seat aircraft, equipping the fighter regiment of the Air Defense Troops (VPVO) service, were modified to this standard by replacing several electronic black boxes in their weapons control system.

Enhanced twin-seaters in VKS service

The VKS fields yet another new-build Flanker derivative, the two-seat Su-30M2 boasting full combat capability, with the first examples taken on in 2011. This is a two-seater with in-flight refueling capability and a maximum warload of 17,600lb (8,000kg), using the basic Su-30 airframe dating back to the early 1990s. Said to be almost identical to the Su-27SM3 single-seater, the mission avionics fit of this enhanced derivative enables the employment of the most-modern (late 2000s) Russian-made air-to-surface guided ordinance.

In August 2009, the new two-seat derivative was ordered together with the newly built Su-27SM3s, with the initial batch for four jets delivered in 2010 and 2011. In December 2012, the Russian MOD placed its second order for 16 more Su-30M2s, delivered between 2013 and 2015. All these enhanced two-seater Flankers are currently used mainly for continuation training and check rides in the Su-27SM/SM3 and Su-35S-equipped squadrons. By June 2021, 19 Su-30M2s remained in active service with the VKS.

In addition, the VKS operates five ‘vanilla’ Su-30s, delivered between 1994 and 1996. All these rare Flanker derivatives serving with the 968th IISAP of the Lipetsk combat training center and, in 2019-2020, were cycled through overhaul to extend their service life until the mid-2020s.

Depleted but still busy fleet

Today, the VKS’ fleet of 40 or so ‘vanilla’ Flankers includes a mixture of nonupgraded Su-27P/S single-seaters and Su-27UB/UBK two-seaters, and is complemented by five 1990s-vintage Su- 30s. These aircraft, manufactured between 1987 and 1993, continue with one frontline and one training squadron, while also partially equipping an instructor-research squadron assigned to the Lipetsk combat training center. A handful of Su-27UBs are believed to still be in active operation with the five Su-27SM/SM3-equipped front-line squadrons. There are also at least two twin-seaters flying with the 929th GLITs (State Flight-Test Centre), the VKS flight test and evaluation center at Akhtubinsk, together with a few Su-27SM/SM3s.

The sole front-line squadron in VKS service, still equipped with non-upgraded single-seat Flankers, is assigned to the 38th IAP (Fighter Aviation Regiment) at Belbek near Sevastopol in Crimea, flying a dozen single-seaters in addition to three more two-seaters. In turn, the training squadron assigned to the 195th UAP at Kushchevskaya, included within the structure of the Krasnodar Higher Military Aviation Pilot School, has a fleet of eight Su-27UBK export-standard two-seaters. The squadron is mainly tasked with the conversion-to-type training of foreign pilots from client countries operating the Su-27/30s of export Flanker derivatives.

The AMVF, in turn, has two front-line air defense squadrons fully equipped with ‘legacy’ Flankers which are both assigned to the 689th Guards IAP, a fighter regiment of the Baltic Fleet stationed at Chkalovsk in the Kaliningrad exclave. Disbanded in 2009 and then re-established in December 2018, the famous fighter unit inherited the aircraft and aircrews of the sole fighter squadron of the now disbanded 72nd Guards Air Base. Currently, its fleet includes over 20 Su-27Ps in addition to four more Su-27UB two seaters. Initially, the newly-established regiment had a fleet of only 13 aircraft; then it began taking additional Flanker-B/Cs in early 2019 in an effort to fully equip its two squadrons. Between January and May that year, the 689th received no fewer than five Su-27Ps previously operated by the 790th IAP, a VKS fighter regiment stationed at Khotilovo in the Tver region. Later, the regiment took additional single seaters, operated previously by the 3rd SAP (Composite Aviation Regiment) at Krymsk, while in 2020, its fleet was further strengthened by two freshly-overhauled single-seaters and one two-seater.

The AVMF also operates a pair of Su- 27UB two-seaters assigned to the 279th OKIAP, a carrier-borne fighter aviation regiment stationed in Severomorsk-3 near Murmansk; it is mainly equipped with single-seat Su-33 desk-capable fighters, with up to a dozen examples believed to be maintained in active service.

While the days of the first-generation Flankers in VKS service are numbered, as the type is projected to be replaced sooner rather than later by the Su-35S, the fleet of newly-built and upgraded Su-27SM3s, which are complemented by the Su-30M2 two-seaters, is to continue in active service for decades to come. In contrast, the AVMF’s front-line fleet of two dozen or so non-upgraded Flankers will continue to ply their trade from Chkalovsk for around five more years, as the naval aviation arm has no funds or ambitions to rapidly upgrade its fleet to boost its otherwise limited combat potential.

As a result, the strategically important Kaliningrad exclave will continue to rely on aging ‘vanilla’ Flanker fleets equipped with single-target engagement radars and a combination of semi-active radar homing (SARH) beyond visual range (BVR) air-to-air missiles, the R-27R and R-27ER, complemented by the R-27T and R-27TE, outfitted with a heat-seeking guidance system and the heat-seeking R-73 for close-in air combat. The first-generation Flankers in AVMF service are expected to eventually be superseded by newly-built Su-30SM2 multi-role two-seaters.

Quick Reaction Alert duty

The 38th and 689th Guards IAPs are tasked with Quick Reaction Alert (QRA) duty on a 24/7 basis under Russia’s integrated air defence system. The 38th polices airspace over the Crimea and the adjacent Black Sea area, while the 689th deals with protection of the equally strategically important and heavily-militarized Kaliningrad exclave and adjacent airspace over the Baltic Sea.

The regiments are among the busiest Russian air defense fighter units. Their aircrews are heavily burdened with QRA responsibility; they frequently scramble to intercept a variety of foreign reconnaissance and bomber aircraft flying in neutral airspace over the Baltic and Black Sea, near Russian borders, to gather electronic and signals intelligence on Russian military installations and ships. The regiments maintain QRA flights at their home airfields, with four aircraft ready for take-off within 15 minutes of receiving the scramble order.

Multiple close encounters between Russian Su-27s and Western aircraft have occurred over recent years. The most widely publicized was August 28, 2020, when QRA Flankers, belonging to the 38th IAP, came dangerously close to a Bomber Task Force Europe B-52H bomber in international airspace over the Black Sea next to the Russian border in Crimea, otherwise known as ‘Russia’s backyard’. Operating in an aggressive manner, the Su-27 pair crossed the US bomber’s flight path within 100ft (30m) of its nose multiple times at co-altitude and while in afterburner, causing strong turbulence and restricting the B-52’s ability to maneuver. This high-visibility and hardline reaction is believed to be consistent with the standard Russian air defense/ air policing procedures to drive away ‘unfriendly’ aircraft.

Chkalovsk is also very busy with the QRA scrambles, with a sharp increase in these operations reported since 2013 rendering the 689th Guards IAP as the busiest Russian fighter unit. Flight time from Chkalovsk to the border line over the Baltic Sea waters around the Kaliningrad exclave is about five minutes and many of the experienced Flanker drivers from the regiment have amassed more than 100 scrambles under their belts. In most cases, this figure is said to have been amassed in fewer than five years, with aircrews scrambled to encounter and shadow Western aircraft flying their recce-gathering missions over neutral waters for prolonged periods in close proximity to the Russian borders.

Another widely covered dangerously close encounter over the Baltic Sea occurred on April 7, 2015, when an Su-27 flew extremely close to a US Air Force RC- 135 flight in a manner which the Pentagon claimed to be ‘unsafe and unprofessional’ with the US government protesting in diplomatic and official channels. The Flanker was said to have passed within 20ft (6.5m) of the RC-135 during this specific QRA scramble.

In December 2019, the Russian MOD official newspaper, ‘Krasnaya Zvezda’ (Red Star), published an article naming the pilot involved in this encounter. On the front page of the newspaper, Capt (then) Vasiliy Antipov shared that he had performed a sharp and precise maneuver, ending near the RC-135, and apparently scaring its pilot. He rejected, however, the US allegations that he had been acting in an unprofessional manner. Moreover, the Russian Navy pilot was decorated with the Order of Bravery for his effective harassment of the US high-value intelligence-gathering aircraft, which eventually led to its prompt retreat from the area of an ongoing operation.

Development and in-service fielding story

The Su-27 heavyweight fighter traces its origins back to 1969 when the Soviet Air Force outlined its initial set of technical and tactical requirements for developing a new-generation air superiority machine. It was viewed as a counter to the US Air Force FX program which eventually resulted in the development of the McDonnell Douglas (now Boeing) F-15 Eagle. The Soviet new-generation fighter program was tasked to develop a heavyweight fighter, well-suited to tight maneuvering in close-in combat, provided with huge internal volume for long-range/ long-endurance air defense operations and capable of being armed with many long and short-range air-to-air missiles; its overall air superiority performance was required to be at least 10% better than the F-15.

Designated as the T10-1, the first prototype of the new fighter made its maiden flight on May 20, 1977, and was soon followed by three more examples. Early in the flight-test program, however, it became clear that the T10 is a seriously flawed design, demonstrating much inferior aerodynamic performance when pitted against its US rival and designer’s benchmark, the F-15. Consequently, the leadership of Sukhoi undertook the risky step of radically redesigning the underperforming and disappointing T10 in an effort to fix its most evident aerodynamic shortcomings.

The end result of this enormous, but otherwise fast-going, effort was the virtually all-new T10S design, the first prototype of which took to the air on April 20, 1981. Amid a compressed and rather troublesome flight test program, the T10S entered series production at the Komsomolsk-on-Amur aircraft plant during 1982, under the in-service designation Su-27.

Entering front-line regimental service during late 1984, the Flanker-B lagged well behind its US rivals F-15A and F-16A. Its formal acceptance, however, in Soviet Air Forces (VVS) and Soviet Air Defence Troops (PVO) service - as a fully combat-capable weapons system – took place not long before August 1990, following completion of the type’s exhaustive testing and evaluation program. Taking to the air for the first time in March 1985, the Su-27UB (NATO: Flanker-C) is a fully combat-capable two-seater built in prototype form at Komsomolsk-on-Amur, followed by a small batch of pre-series aircraft for testing and evaluation.

The two-seater entered serial production at the aircraft plant in Irkutsk (now known as IAZ or the Irkutsk Aviation Plant, part of Irkut corporation) the following year, with the first production example taking to the air in September 1986. Retaining most of the single-seater’s design, the Flanker-C’s systems remained unchanged, with its second cockpit added by reducing fuel capacity. The new, remarkably agile, fast-climbing, well-armed and long-legged air superiority fighter was firstly taken on by the PVO regiments and, several years later, the VVS’ frontal aviation arm followed suit.

By the end of the Cold War, just before the Soviet Union broke up in late 1991, the combined Flanker-B/C inventory in Soviet service (both in the PVO and VVS arms) numbered just over 400 examples, including some 100 two-seaters. These Su-27S/P/UBs equipped 17 PVO fighter-interceptor regiments, in addition to four VVS front-line fighter regiments, two combat training and aircrew conversion centers and one air display squadron.

The type’s production for domestic use ended in 1992-1993 and by 2001, the Russian air arm had over 300 airframes. In early 2013, some 180 of these Flankers remained in active service, with ten front-line and two training squadrons, one display team and a test and evaluation unit. In addition to the high-intensity QRA duty, the Chkalovsk Flankers are also often tasked to escort VKS aircraft, including frontal and strategic bombers performing long-range patrol operations over the Baltic Sea while operating from bases in mainland Russia. Another important mission assigned to the 689th Guards IAP calls for the escort of VKS transport aircraft with VIPs onboard, as well as intelligence-gathering air platforms transiting between mainland Russia and the Kaliningrad District.

Still going strong

Currently, the VKS operates a fleet of more than 40 upgraded Su-27SM/SM3s serving with three front-line squadrons, while five more examples were delivered to the Flanker-equipped squadron of the 968th IISAP (Instructor-Research Composite Aviation Regiment), assigned to Lipetsk-based combat training center. A handful of fighters are also operated by the VKS 929th Flight-Test Centre in Akhtubinsk.

In total, 55 first-generation single-seat Flankers (including two prototypes) were cycled through an upgrade at the company today known as KnAAZ (the Komsomolsk-on-Amur Aircraft Plant, a fully-owned Sukhoi subsidiary), between 2003 and 2009. Three of these were subsequently lost in flying accidents, while others have been grounded due to expired service life or time between overhauls.

The mid-life upgrade package for the baseline Su-27S/P Flanker-B was developed by Sukhoi for the Russian air arm fleet in an effort to beef up the combat capability in the air-to-air role and add air-to-surface guided weapons to the fighter’s arsenal. Taken from the last Su-27P production batch, the Su-27SM prototype was upgraded at KnAAZ and test-flown for the first time in December 2002.

The first production-upgraded Flankers were taken on strength by the VKS’ 4th Combat Training and Aircrew Conversion Centre at Lipetsk in December 2003, for the so-called experimental operation, and the Su-27SM was formally commissioned in Russian service in 2004. Stationed at Dzemgi airfield near Komsomolsk-on-Amur in Russia’s Far East, the first front-line unit, the 23rd IAP, received a batch of six Su-27SMs in December 2004. The last of 24 upgraded single-seat Flankers to fully equip the two fighter squadrons of the Dzemgi-based regiment were delivered in September 2006.

The second front-line unit to receive the Su-27SM was the 22nd Guards IAP at Tsentralnaya Uglovaya airfield, also in Russia’s Far East, not far from the big port city of Vladivostok. It took on an initial batch of 12 aircraft in 2007-2008 to equip one of its two Flanker squadrons, while the delivery of the second dozen of Su-27SMs was reportedly completed in September 2009.

Replacing the Su-27SMs with newly built Su-35Ss in the 23rd IAP began in early 2014, with two of its squadrons fully-equipped with this new-generation Flanker derivative by the year-end, while the upgraded Flanker continued to serve with one squadron of the Dzemgi-based regiment. Then, the 22nd IAP went on to replace the Su-27SMs in one of its Flanker-equipped squadrons with Su-35Ss and a portion of the surplus upgraded Flankers were handed over to the newly established 38th IAP at Belbek. This regiment, situated next to the big port city of Sevastopol in Crimea, took on a total of 12 Su-27SMs in November 2014 which had previously been operated by the 22nd and 23rd IAPs. Later two of these were returned to the 23rd IAP.

Ex-22nd IAP Su-27SMs were also taken on by the 159th IAP at Besovets. In December 2015, the first deliveries partially equipped its two squadrons, where the upgraded Flankers served shoulder-to-shoulder with non-upgraded Su-27P/UBs until early 2019. In addition, several of the former 22nd IAP’s Su-27SMs were handed over to the 790th IAP at Khotilovo, with the first deliveries reported in mid-2016.

The type continued in service with one squadron there until late 2020, serving with freshly-overhauled ‘vanilla’ Su-27Ps. Finally, in 2020, the 38th IAP took at least six additional Su-27SMs which had previously been operated by the 790th IAP; the single Flanker squadron took on 12 newly-built Su-35Ss between January and October 2019.

In August 2009, the Russian MOD placed an order for 12 newly-built single-seaters with vastly improved avionics and mission equipment, designated as the Su-27SM3, together with four Su-30M2s with similar equipment and avionics outfit. In 2011, these Flankers were taken by the frontline unit now known as the 3rd SAP, a two-squadron composite regiment stationed at Krymsk in the southern part of Russia, next to the big Black Sea port city of Novorosiisk. These much-enhanced Flankers were then augmented between 2014 and 2018 by 12 more upgraded Su-27SM3s.

This time, they were converted from existing airframes and were cycled through a deep structural overhaul and a life-extension program at KnAAZ in a bid to extend the jet’s service life to 40 years and 2,000 flight hours. However, the original VKS procurement plans called for the upgrade of no fewer than 36 existing ‘legacy’ Flankers to the SM3 standard, under a contract inked in mid-2015 between MoD and Sukhoi, but this has proved to be a protracted effort.

The first four production standard upgraded examples were not handed over to the VKS before December 2017. By 2018, its eventual scope was reduced to 12 airframes only, including the two initial examples already taken in service during 2014 for an experimental operation. Currently, all the upgraded Su- 27SM3s serve with the two-squadron 3rd SAP at Krymsk.

SM/SM3 upgrade explained

Based around the SUV-27E enhanced weapons control system, the Su-27SM avionics standard for upgrading the existing Flanker fleet uses the significantly improved-performance N001V Mech-M multi-mode radar. The upgraded radar retains the existing twist-cassegrain mechanically scanned antenna and comes endowed with a vastly increased computing power compared with the original version.

Its newly-introduced air-to-air mode supports a simultaneous engagement of two targets, while the maximum detection range against a large-size fighter target was increased up to 81nm (150km) and small-size fighters can be seen at up to 59nm (110km). The aircraft was able to deploy the new R-77-1 (RVV-AE, AA-12 Adder) active-radar BVR air-to-air missile. In addition, the N001V boasts newly added air-to-surface modes, thanks to an add-on signal processing channel, that includes surface search, real-beam ground mapping, Doppler sharpening and moving target indicator.

The new air-to-surface modes also enable the use of the Kh-31A (AS-17 Krypton) and Kh-35U (AS-20 Kayak) anti-ship missiles. The upgraded radar can also provide initial cueing of TV-guided weapons, to be unleashed by the pilot after visual target acquisition and identification using the weapon’s own TV seeker, such as the Kh-29T missile (AS-14 Kedge) in addition to the KAB-500Kr and KAB-1500Kr guided bombs.

Furthermore, the N001V enables bombing runs against radar-reflecting surface targets at night, and in poor weather, without visual aiming thanks to the newly-introduced range-finding mode. The newly-integrated L150-27.2 Pastel radar homing and warning system enables the upgraded heavyweight fighter to be used in suppression of enemy air defense (SEAD), providing targeting for the Kh-31P high-speed anti-radiation missile and its improved derivative, the Kh-31PD.

Installed offset to starboard, the aircraft’s 52Sh infrared search and track (IRST) sensor is capable of lasing ground targets at up to 5.4nm (10km) range; it is also useful for targeting laser-guided weapons while boasting extended range in the air-to-air mode. The SM’s man-machine interface was considerably improved thanks to a complete redesign of the cockpit, with three LCD displays (two 7x5in MFI-9s with a smaller one between them). There are also a number of back-up instruments and the new SILS-27 head-up display, complemented by the Berkut-1 video recording system and a mission planning and flight management system. The new mission avionics list also includes an improved datalink for intra-aircraft tactical information exchange in group operations or for the exchange of information with airborne and ground command-and-control facilities.

Also in possession of a new communications suite, the Su-27SM’s navigation system was enhanced by the integration of the A737-010 GLONASS/GPS satellite positioning receiver. The increased-thrust AL-31F-M1 engines, rated at 29,754lb (132.44kN) at maximum afterburner and with military thrust rating of 18.320lb (81.49kN), were used for the first time to power a batch of upgraded Su-27SMs, delivered in 2008.

Using two Su-27SMs upgraded to the new configuration, the enhanced SM3 standard was tested from 2008-2010. SM3-standard was then adopted for the first time for the last batch of 12 newly built Flankers, handed over in 2010 and 2011, introducing a further improved cockpit with four LCD displays and no back-up analogue instruments. The SM3’s further upgraded N001VM radar features extended detection and tracking ranges, while also adding a datalink to support mid-course guidance of the R-77-1 extended-range, active-radar air-to-air missiles. Advertised as capable of guiding two active-radar BVR missiles against two targets, the SM3 boasts an improved electronic countermeasures (ECM) system, the two-pod L265M10 Khibini-M and an all-new communication suite with secure and jam-resistant modes of operation. Also powered by AL-31F-M1 afterburning turbofans, the Su-27SM3’s take-off weight increased by some 6,612lb (3,000kg) compared with the 'vanilla' Flanker and comes with 12 hardpoints for carrying ordinance and ECM pods. The Su-27SM3 is also endowed with the capability to use the new KAB-500S 1,102lb (500kg) satellite/INS-guided bomb.

According to Sukhoi, the Su-27SM3 standard boasts three times better air-to-air combat capability, while in the air-to-ground role, it is claimed to have two times better combat effectiveness than its predecessor, Su-27S.

Su-27/30 operators

Abbreviations: Fighter Aviation Regiment (IAP); Composite Aviation Regiment (SAP); Instructor-Research Composite Aviation Regiment (IISAP); State Flight-Test Centre (GLITs); GTsPAPVI - State Personnel Training and Aircraft Field-Testing Centre); Training Air Base (UAB)