Russia begins testing two-seat variant of Su-57 Felon

Russia begins testing two-seat variant of Su-57 Felon

Russia has begun taxi testing of a two-seat variant of the Su-57 with a new cockpit reminiscent of the Su-30 Flanker, according to a post on the popular FighterBomber Telegram channel.

On May 16, 2026, it was claimed that a two-seat variant of the Su-57 Felon is currently undergoing taxi trials. The information was shared by the leading Russian Telegram account ‘FighterBomber’, which is affiliated with many Russian Aerospace Forces (RuAF) units and provides crowdfunded supplies of everyday military accessories and equipment.

The same channel posted the photo a day later and said it was a real aircraft taken during testing. The authenticity of the image cannot be confirmed at this time.

Therefore, with the advent of this new variant, the Su-57 will become the second fifth generation fighter to have a two-seat variant. In fact, the first was the J-20 with the ‘S’ variant (J-20S), first discovered in 2021.

FB also speculated on a possible designation for the aircraft. “As part of today’s testing, a new two-seat modification of the Su-57 performed a rollover. We will see whether it will be called Su-57D or Su-57UB. Alternatively, it may be called Su-57ED,” the post said.

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Images of the Su-57, believed to be a two-seater, are being reported as real by multiple sources. The background is so blurry that it’s impossible to determine where the photo was taken.

Notably, the aircraft shows no identifying markings and appears to have been edited, with only a small area visible behind the cockpit. However, military aviation researcher Andreas Rupprecht shared that the aircraft was marked with boat number “055 Blue”.

This boat number is the same as that already used on the fifth flying prototype T-50-5, which was badly damaged in an engine fire in 2014 and rebuilt as the T-50-5R, although it is still debatable whether this is the T-50-5 rebuilt after the accident with the T-50-6 prototype, complete with salvageable parts from the T-50-5. Either way, the Bort number could point to the possibility that an existing airframe was modified to obtain the two-seat Su-57.

The cockpit layout is reminiscent of the Su-30, but the height difference between the two seats is more pronounced in the Su-57. However, the choice you make will increase visibility for crew members in the back seat.

A new logo featuring the shapes of the Su-57 and S-70 Okhotnik drones can also be seen on the tail. Previous prototypes also featured similar logos, but it is unclear whether this points to the twin-seat Su-57’s role in drone management.

Okhotnik Bombing Test 2Okhotnik Bombing Test 2
The S-70 Okhotnik is undergoing test flights alongside the Su-57. (Image source: Russian Ministry of Defense)

There are no other immediately noticeable differences compared to the single-seat Su-57. However, changes can be expected internally as systems may need to be moved to make room for a second crew member and structural modifications may also be required to make this possible.

The role of the second crew member is not yet known, but the second seat could allow an instructor pilot or weapons systems officer to board the aircraft. According to the 2023 patent description, the focus will likely be on the latter.

Patent for two-seater stealth fighter in 2023

There were also indications that a two-seat stealth aircraft was in the works, with a patent filed with Russia’s Federal Intellectual Property Office (FSIP) in May 2023. The patent, registered with FSIP on November 17, 2023, is for a “multi-role two-seat low observable tactical aircraft” and looks very similar to the Su-57 and Su-30.

The aircraft is “designed to detect and destroy air, ground and surface targets at supersonic and subsonic flight speeds at a wide range of altitudes and also serves as an airborne command post for network-oriented operations of mixed aircraft groups.”

The patent itself draws attention to the Su-30 family of jets, the only two-seat fully multirole aircraft in the RuAF inventory. The Su-34 Fullback, also a two-seater but with a side-by-side seating arrangement, is primarily an aerial interdiction bomber.

Russia Su 57 Twin Seat 2Russia Su 57 Twin Seat 2
An unidentified two-seater low-observable aircraft included in a patent submitted by UAC in May 2023. (Image source: Federal Intellectual Property Service)

It is not known how the two-seater aircraft covered by the patent is related to the Su-57 and Su-30. We also don’t know if the new two-seat Su-57 originated from this patent.

This patent may have everything to do with the new stealth aircraft we may see in the future. The patent itself could be an academic exercise, if necessary, to lay the foundation for theoretical research on such a fighter aircraft and to accelerate the development schedule if RuMoD and RuAF pursue such efforts.

However, the aerodynamic configuration described in the document is very similar to the Su-57.

“The multi-functional two-seater low-vis aircraft with integrated aerodynamic configuration consists of a set of built-in equipment, a fuselage with extensions, wing consoles with high-lift devices on the leading and trailing edges, including flaperons, ailerons and rotary wing leading edges, an all-moving horizontal and twin-fin vertical tail console mounted on the side tail booms of the fuselage, a two-seater cockpit with canopy, fairing and radar, an antenna fairing located in the leading part of the fuselage, horizontally placed and airborne. The power plant with its inlets, located in the engine nacelle, its axis oriented at an acute angle to the plane of symmetry of the aircraft in the direction of flight. The aircraft is characterized by the fact that the wing consoles are smoothly connected to the fuselage, the fuselage extensions are located above the engine air intakes, and the aircraft engines contain jet nozzles with deflectable thrust vectors and thrust reversers (…).

Much emphasis is placed on descriptions suggesting sensor fusion and satellite-based advanced communications and tactical links capable of operating in harsh environments.

“The equipment on board is designed to enable information interaction between different types of aircraft in the group, including the reception and transmission of data through high-speed communication channels, including satellite communication channels, and group communication, as well as the analysis of information received from its own systems and external sources and the subsequent issuance of recommendations to the crew and/or orders to the group of aircraft.”

The patent notes that the Su-30 family is closest to the aircraft in the patent, and other Western Gen. 4.5 Aircraft Refers to a two-seat jet.

“Currently the following multi-purpose two-seat tactical aircraft are known: Dassault Rafale, Eurofighter Typhoon EF-2000, Saab JAS-39NG Grippen, Boeing F/A-18F Super Hornet, McDonnell-Douglas F-15D, Cy-30MK family of aircraft, MiG-35. Among the similar aircraft mentioned above, the closest one is the Su-30MK family.”

Su-57 Recent Developments

The Su-57 is manufactured at United Aircraft Corporation’s (UAC) Komsomolsk-on-Amur aircraft plant in the Khabarovsk region in the Russian Far East, and as of December 2025, 24 airframes have been delivered to the RuAF. World Air Force 2026 report.

UAC reported more deliveries in February 2026, with Russian military aviation analyst Guy Plopsky counting at least two airframes, bringing the known number to 26. These aircraft are also noticeably different and probably have improved Heads-Up Displays (HUDs), self-defense equipment, new Missile Approach Warning Sensors (MAWS) and Directional Infrared Countermeasures (DIRCM).

At the Dubai Airshow in November 2025, the Su-57 airframe T-50-9 also introduced a single widescreen display instead of the older multi-function display (MFD).

The Su-57 was also tested using the more powerful Izdeliye 177 (Product 177) engine in December 2025. This is reportedly an option for future production batches, possibly replacing the previous Phase 1 (Izdeliye 117) AL-41F-1S and Phase 2 (Izdeliye) AL-51F-1.

Photos earlier that year revealed the interior of the Su-57’s rear, front and side weapons bays, and in December 2024 the aircraft was also discovered to have a single planar 2D thrust vectoring nozzle. Algeria has also been confirmed as the first Su-57 customer with a full fleet of 12 units, with at least two confirmed so far.

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