Su-57D: Russia’s Stealth Fighter Becomes an Airborne Command Post

Su-57D Maiden Flight

On May 19, Russia’s UAC announced that the Su-57D — a two-seat variant of the Su-57 — had undertaken its maiden flight and commenced flight testing.

During the maiden flight, the aircraft was flown by a single pilot, Sergei Bogdan, the chief test pilot of the Sukhoi Design Bureau.

The Su-57 is designed for single-seat operations. Situational awareness, AI decision assist, and automation have been extensively used to allow a single pilot to handle the cockpit workload.

Imperative for Two-Seat Variant

To begin with, Russian forces didn't feel the need for a two-seat variant. However, much has changed since the stealth fighter first flew in 2010. Based on advances in combat aviation technology and the experience of the Russian Aerospace Forces in Ukraine, Russia's Ministry of Defense has now ordered a batch of the twin-seaters.

It is widely understood that a twin-seat variant facilitates speedier pilot training and operational conversion, as well as manned-unmanned teaming (MUM-T) of combat aircraft operating as a drone mothership.

The Su-57D is reportedly capable of teaming up with four S-70 Okhotnik modular drones configured for roles such as SEAD, electronic warfare, reconnaissance, and aerial combat. Notably, the control and coordination demands of MUM-T operations are far beyond what a single pilot can handle, even using sensor fusion and AI assistance.

Following the Su-57D's maiden flight, Bogdan, during his interaction with the Russian press, highlighted yet another important role that would require a second seat. He stated that the co-pilot of the Su-57D would be able to command an air group directly in the air, thousands of kilometers away from base. It is important to understand what Bogdan was alluding to because it highlights another emerging, path-breaking trend in combat aviation.

Important Cues from the Su-57D Patent

In November 2023, Russia's United Aircraft Corporation published a patent for a multifunctional two-seat stealth aircraft, which has now been unveiled as the Su-57D.

Based on a copy of the patent, TASS reported that the two-seat stealth tactical aircraft would be designed to detect and destroy air, surface, and ground targets.

The patent document acquired by TASS referred to the aircraft as “...a multifunctional two-seat stealth tactical aircraft... intended to detect and destroy air, surface, and ground targets at super- and subsonic flight speeds across a wide range of altitudes, as well as act as an airborne command post for network-oriented operations involving mixed groups of aircraft.”

To reiterate, the document noted that the twin-seat variant would retain its ability to destroy targets with guided and unguided weapons. In addition, it would be possible to use the new variant as an air control point with the ability to ensure coordination between aviation and military formations, as well as serve as a control point for unmanned aerial vehicles.

Air Command Role

For several years now, the RuAF has been evaluating the use of the Su-57 for cooperative operations with manned fighters such as the Su-35.

In June 2020, TASS reported that Russia had tested Su-35–Su-57 cooperative operations.

“The experiment was carried out in real combat conditions. A group of Su-35 fighters was involved in the ‘flock’; the role of the command-and-staff aircraft was performed by the Su-57,” a source told TASS.

More recently, as part of the ongoing conflict in Ukraine, Su-57 fighters have teamed up with S-70 Okhotnik UCAVs to strike targets in Ukraine.

Su-57D Redesign

Pivotal to the Su-57D's role as a command post would be long endurance and range, which would necessitate a significant increase in the fuel carried internally by the aircraft.

The redesign of the Su-57 airframe to realise the Su-57D is aimed not only at creating space for a second cockpit but also at increasing internal fuel capacity. In other words, the Su-57D variant will carry more fuel internally than the Su-57 fighter. Usually, twin-seat variants carry less fuel than the single-seat fighter because the second seat is fitted while retaining the fighter version's dimensions.

It is clear that, in the case of the Su-57D, Sukhoi has departed from the norm to facilitate its MUM-T and command-post roles.

Optionally, the Su-57D can also carry additional fuel in tanks fitted into the weapon bays normally used for the internal carriage of missiles and bombs.

It is also possible that, by increasing the dimensions, Sukhoi has created additional space for the avionics required to support MUM-T and command-post roles. Perhaps the avionics could also go into the weapon bays?

As such, it is highly likely that the Su-57D can be configured either for a combat role or for a command-post role, but not both simultaneously.

Conclusion

The option to carry additional fuel in the weapons bays of the Su-57 is an interesting innovation that increases the versatility of the stealth fighter.

With the Su-57, Russia appears to be following the same approach that the Soviet Union successfully pursued after developing the Su-27 — continuously reinventing the aircraft to meet the challenges and opportunities emerging from technological advances.

The Su-27, officially inducted into the Soviet Air Force in 1985, evolved into several Su-30 variants, the Su-34, the Su-35, and the J-11, all of which remain in service to this day. The evolved variants of the Su-27 will likely remain in service for at least a couple of decades more.

It is highly likely that Su-57 variants will similarly remain in service for the next 50 years.