Way back in December 2020, Russia’s Military-Industrial Commission hinted that India was interested in the Su-57’s twin-seater version.

Three years later, in November 2023, Russia’s United Aircraft Corporation (UAC) received a “patent for a two-seat multifunctional airplane” with the drawings suggesting that “the prototype of the multifunctional airborne control centre is the fifth-generation Su-57 fighter”.

Trials Of Twin-Seater Su-57 Start 

On May 17, a Telegram channel with close ties to the Russian Aerospace Forces posted an image of a Su-57 two-seater claiming it is undergoing taxi trials, or pre-flight ground testing.

The redesigned forward fuselage and the tandem two-seat cockpit resemble those of the Su-30 and the Su-27 UB. Like the Su-30MKI used by the Indian Air Force (IAF), the Su-57’s rear seat was significantly higher than the front.

Now, Russia’s UAC has confirmed that the Su-57D’s first test flight was conducted at the Sukhoi Design Bureau.

“Flight tests have begun on the prototype of the Su-57, a fifth-generation two-seater fighter. This aircraft … also possesses the capabilities of a combat trainer and a command-and-control aircraft,” said Denis Manturov, Russia’s First Deputy Prime Minister. The Su-57’s NATO reporting name is “Felon”.

India, Russia And Fifth-Generation Jet  

Indian-Russian fighter jet collaboration goes a long way. Hindustan Aeronautics Limited (HAL) has been producing the Su-30MKI, a 4.5-generation air superiority and multirole fighter, since 2004.

India showed interest in a Russian fifth-generation warplane in late 2000. By 2010-end, India and Russia signed a deal to develop a Fifth Generation Fighter Aircraft (FGFA) based on 43 improvements in the Su-57. India was to get 166 single-seaters built by Sukhoi and 48 twin-seaters manufactured by HAL.

However, India withdrew from the project in 2018 for several reasons: the lack of proper stealth and a “modular engine concept”, doubts about the power of Saturn AL-41F afterburning turbofan engines and Russia’s refusal to share the Su-57’s flight computer and mission software.

Why India Needs Su-57 Twin-Seater

Last year, Russia’s state-owned defence export company Rosoboronexport offered the Su-57E (export version) to India and its local production at the Aero India 2025 show.

The Su-57 is “needed by the Indian Air Force as the next step in the evolution and development of our aviation industries,” UAC CEO Vadim Badekha told the Russian media.

In January this year, Badekha said at the Wings India airshow in Hyderabad that Russia and India are in a “deep technical stage” of negotiations on purchasing the fighter and also discussing the “production of the Su-57 at the facilities used to produce the Su-30MKI”.

India urgently needs a fifth-generation fighter jet for several reasons.

First, a year after the Operation Sindoor humiliation, the Pakistan Air Force (PAF) announced an “initial collaborative agreement” earlier this month to acquire 30-40 of China’s second fifth-generation fighter.

The first batch of the twin-engine Shenyang J-35AE Cloud Dragon (the export version of the land-based variant) is expected by year-end. “It will give them [Pakistan] an advantage,” Air Chief Marshal A.P. Singh had said in March last year after Pakistan approved the purchase in January.

Besides, the PAF is part of Turkey’s KAAN fifth-generation fighter project with a joint manufacturing factory planned in Pakistan.

Second, China’s first and best fifth-generation stealth fighter, the twin-engine J-20 Mighty Dragon, now has a more advanced variant, the J-20A, and a twin-seater variant, the J-20S.

While the J-20 was built to counter America’s best stealth fifth-generation fighter, the twin-engine F-22 Raptor, the J-35, was designed to counter the F-35.

Moreover, China is developing two sixth-generation jets with prototypes already flown. The triple-engine J-36 and the twin-engine J-50 are meant to counter the US sixth-generation twin-engine B-21 Raider and the F-47 respectively.

Third, India’s 5.5-generation Advanced Medium Combat Aircraft (AMCA) is a 10-year project launched in 2024, which means production will not begin before 2035. Besides, the prototype will not be ready before 2026-27, and the first test flight will not be before 2028.

The IAF seeks seven AMCA squadrons (126 aircraft) in two phases, but HAL’s LCA Tejas Mk-1A project is already behind schedule.

Fourth, the Su-57 suits the IAF not only for its stealth, sensor-fused combat, supermanoeuvrability and supercruise features, but also for its heavier long-range missiles. Its two beyond-visual-range (BVR) missiles enable the pilot to engage targets at extreme distances.

Su-57 has six internal and external hardpoints each.

The two BVR missiles are the R-37M “AWACS and C4ISTAR jet Killer” (speed Mach 6 and range around 400 km) and the R-77M (speed Mach 4 and range around 200 km).  

For close combat, the Su-57 has the R-74M2 short-range, infrared-homing air-to-air missile (speed Mach 2.5 and range of 20-40 km).

It can carry the air-launched variant of the nuclear-capable Mach 9 3M22 Zircon anti-ship, land-attack cruise missile, usually launched from surface ships and submarines, with a maximum range of 1,000 km.

The Su-57 also carries the nuclear-capable Kh-102 air-launched cruise missile (ALCM), which has a range of more than 3,500 km.

Russia has also developed a mini version of the Mach 10 nuclear-capable Kh-47M2 Kinzhal air-launched ballistic missile that can fit inside the Su-57’s internal weapons bay. The missile can strike targets 2,000 km away.  

The Su-57 has three types of air-to-surface missiles. The stealth subsonic Kh-69 ALCM (range 290 km), the Kh-38M tactical missile (speed Mach 2.2 and range 70 km) and the S-71K “Kover” low-observable subsonic ALCM (range 300-350 km).

The Su-57 also carries two anti-ship missiles. The Kh-35U turbojet subsonic cruise missile (upgraded version range 300 km) and Kh-31A (speed Mach 3.5, range 70 km).

The Kh-58UShKE is an anti-radiation missile (speed Mach 3.6 and range 245 km) designed for SEAD (Suppression of Enemy Air Defences) missions.

Fifth, India’s concerns about the power of AL-41F afterburning turbofan engines could be addressed if Sukhoi combines the improvements in the advanced Su-57M variant with the Su-57 twin-seater.

The Su-57M’s new AL-51F-1 turbofan engine has several advantages: increased stealth, thrust, speed and range, and reduced weight, maintenance and operational costs.  

The engine will provide the Su-57M with one of the highest afterburner thrusts — the temporary, massive boost (50%-100%) to a jet engine’s power when extra fuel is injected into the exhaust stream — of any fighter jet globally.

AL-51F-1’s afterburner thrust is 42,000 lbf (pound-force, the standard imperial unit used to measure the thrust produced by a jet engine). The J-20 with advanced WS-15 engines reportedly produces 44,000 lbf and the J-35 26,000 lbf.

Moreover, the Al-51F-1’s flat nozzles, which minimise the rear radar cross-section, and new radar-absorbent materials in the airframe increase the Su-57M’s stealth.

‘Drone Commander’ In Su-57 Twin-Seater 

The Ukraine War and the Iran War have proved the lethality, reach, and capability of drones in countering a superior military power.

The Su-57 twin-seater takes drone warfare to a new level. It’s a drone command-and-control centre with the Weapon Systems Officer (the second crew member) controlling combat, reconnaissance and electronic warfare drones.

The S-70 Okhotnik-B serves as the Loyal Wingman alongside the Su-57 fighter, undertaking SEAD missions and conducting precision strikes on high-value targets, battlefield reconnaissance and electronic warfare.

Its 2,800 kg payload of guided and unguided munitions is distributed in two internal weapons bays.

The drone can carry the KAB-series precision-guided bombs ranging from 250 kg to 1,500 kg (range 3 km-200 km), UMPB D-30SN precision-guided glide bomb (weight 250 kg and range 90-120 km), Kh-38 and Kh-59Mk2 anti-ship, land-attack ALCM (range 290 km), R-73 air-to-air missile (speed Mach 2.5 and range 30-40 km) and dumb bombs (250-500 kg).

In 2021, the Military Industrial Commission said that several Okhotnik drones could be controlled by the Su-57.

Both the Su-57 and Okhotnik can also house the kamikaze S-71M Monochrome stealth drone, which can also be carried externally.

The S-71M, a hybrid between a missile and an autonomous drone, uses optical guidance and target recognition technology to navigate to the target without relying on satellite navigation. With a 100-150-kg payload, it can carry different types of warheads, such as penetrating high-explosive fragmentation, high-explosive and shaped-charge types.

The Su-57 also carries a swarm of Molniyas, mini-60-kg stealth drones with a 5-kg payload and 200-km range. Guided by laser, optronics, and Russia’s Global Navigation Satellite System or radar, the Molniya can strike enemy radars, conduct reconnaissance and jam devices.

(Aninda Dey is a columnist with more than two decades of experience in journalism. Views are personal.)