Russia details roles for its two-seat Su-57D fighter

Russia’s state defense conglomerate Rostec disclosed new details this week on the two-seat Su-57D fighter, a designation in which the “D” likely stands for “Demonstrator,” saying the aircraft is intended for two main roles: training pilots on flight regimes that cannot be replicated on ground simulators, and serving as an airborne control platform for uncrewed aircraft.

The two-seat prototype, which first flew in May, is currently undergoing flight testing. Rostec described the aircraft’s second role as central to what it called sixth-generation technology, since the rear cockpit allows the fighter to function as an airborne command post for drone operations.

“This is important for controlling highly intelligent systems such as the Okhotnik, as well as swarm and group systems, when the attention of the main pilot and crew is focused on carrying out the primary combat mission,” said Mikhail Strelets, director of the Sukhoi Design Bureau, part of Russia’s United Aircraft Corporation, speaking on the program “Military Acceptance.”

Rostec said the two-seat variant will also serve as a testbed for combat artificial intelligence systems currently under development by specialists at United Aircraft Corporation.

The aircraft flying today was not built from scratch. Aviation researcher Andreas Rupprecht identified the prototype by its bort number, 055 Blue, matching the fifth Su-57 flight-test prototype, T-50-5, which suffered a severe engine fire on the runway at Zhukovsky in 2014, reportedly witnessed by an Indian delegation. The airframe was rebuilt as T-50-5R and has now been reconfigured with a second cockpit rather than replaced with new-build hardware.

Some Western defense analysts and outlets, including The Defence Blog, have described the two-seat program’s public framing as only part of the picture. Analysts have suggested the aircraft was built in connection with a series of potential export contracts, intended to demonstrate the program’s readiness to prospective foreign buyers rather than to meet a purely domestic training requirement. India has been named as a country with particular interest in a two-seat configuration, drawing on its operational experience flying the two-seat Su-30MKI.

Russia and India signed a contract in 2010 for preliminary design work on the Fifth Generation Fighter Aircraft, a joint program based on the T-50 prototype that specifically required a two-seat variant. India withdrew from that program in 2018 following disputes over cost, workshare and the aircraft’s stealth performance. Russia has continued pitching a two-seat Su-57 to India in 2026, presenting the offer at the Wings India exhibition in Hyderabad, including proposed technology transfer and integration of Indian-origin weapons such as BrahMos and Astra missiles, according to Indian defense reporting. India has not indicated whether it will accept.

The two-seat prototype’s tail carries a logo depicting both the Su-57 silhouette and the S-70 Okhotnik stealth drone, a visual pairing that matches Rostec’s stated goal of using the aircraft to coordinate crewed and uncrewed formations.

Rostec has not disclosed a production timeline, a finalized designation for the aircraft, referred to variously as Su-57D or Su-57UB in Russian reporting, or a target date for integrating the combat AI systems it says the program will help develop.

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