India Walked Away from the FGFA. The Need for a Twin-Seat Stealth Fighter Did Not!

 The Fifth Generation Fighter Aircraft (FGFA), which India and Russia once planned to co-develop, was envisioned as a two-seat variant of the Su-57.

The IAF’s requirement was never for a stealth fighter — it was, and likely continues to be, for a twin-seat stealth fighter!

It's likely that the IAF’s preference for a twin-seat fighter was based on its experience operating the Su-30MKI. Besides pilot training and operational conversion, a twin-seat fighter could also support multi-role operations benefiting from a second crew member, such as complex strike coordination, electronic warfare/attack roles, and reconnaissance.

The reported reasons for India opting out of the FGFA program — lack of supercruise and unproven operational capability — were always unconvincing, considering that India, as a co-developer of the fighter, would eventually have addressed those shortcomings.

The Rationale for a Twin-Seat Stealth Fighter

All 4th-generation fighter development programs foresaw the eventual need for a twin-seat variant. The initial designs provisioned for a second seat, usually by placing a fuel tank and relocatable electronics behind the cockpit. That space could later be utilized for a second cockpit by moving the electronics and dispensing with the fuel tank.

Stealth fighter development programs for the F-22 and F-35 chose to depart from the twin-seat convention for the following reasons:

1. A twin-seat configuration compromises stealth shaping to some extent.

2. It reduces internal fuel-carrying capacity, thereby compromising range. (Stealth fighters cannot carry fuel externally in drop tanks.)

3. The fighters were primarily designed to penetrate contested airspace; it was believed that sensor fusion would be adequate to enable a single pilot to fly such missions.

In brief, it was believed — with good reason — that twin-seat stealth fighters would add complexity, reduce internal fuel or payload in some cases, and increase radar cross-section.

MUM-T Operations

It has now been clear for several years that the choice of single-seat-only stealth fighters did not anticipate the emergence of the requirement for Manned-Unmanned Teaming (MUM-T) operations.

The Su-57D, for example, is reportedly designed to team up with four S-70 Okhotnik modular drones configured for roles such as SEAD, electronic warfare, reconnaissance, and aerial combat. The control and coordination demands of MUM-T operations far exceed what sensor fusion and AI alone can enable a pilot to manage.

South Korea's KF-21 Boramae Stealth Fighter

South Korea followed a pragmatic approach in developing its KF-21 stealth fighter — an approach that is paying rich dividends in terms of meeting performance and development timeline goals.

Specifically:

The KF-21 features significant reduction in RF observability rather than all-aspect low observability. (To achieve the latter, it would have required materials that the nation had not yet developed.)

The KF-21 features a twin-engine, semi-stealth design with external weapons carriage (no internal weapons bay in the early blocks).

Of the six prototypes built, two were twin-seat variants.

The first prototype rolled out in April 2021 and flew in July 2022. All prototypes collectively conducted roughly 1,600 sorties over 42 months of incident-free flight testing, achieving supersonic flight, aerial refueling, and weapons integration. System development concluded in early 2026.

The first serial-production KF-21 to roll out in March 2026 was, significantly, a trainer!

Initial deliveries to the ROKAF are slated for the second half of 2026, with 40 Block I aircraft targeted by 2028 and up to 120 total aircraft (including Block II) by 2032.

Block I prioritizes air superiority; Block II will add full multirole air-to-ground and anti-ship capabilities. Block III variants will address stealth shortcomings and include internal weapons bays.

The two-seat variant will play a pivotal role. It will not only accelerate pilot training and operational conversion but also facilitate the development of advanced variants and future concepts such as loyal-wingman operations.

An electronic warfare/attack variant — the KF-21EA — is planned, with a dedicated Electronic Warfare Officer (EWO) station in the rear cockpit.

China's J-20S

Ahead of the KF-21, China’s J-20S — a two-seat variant of the Chengdu J-20 Mighty Dragon — became the world’s first operational twin-seat fifth-generation stealth fighter.

The fighter was unveiled at the 2024 Zhuhai Airshow.

Prototypes first flew in 2021; the aircraft entered, or approached, PLAAF operational service in 2025, with frontline markings appearing by mid-year.

The J-20S is reportedly optimized for combat (MUM-T operations), not training or operational conversion. The second crew member — a Mission Systems Officer — manages MUM-T-related sensor fusion, electronic warfare/jamming, and tactical command and control.

While the pilot focuses on flight and air superiority, the Mission Systems Officer directs loyal-wingman drones for coordinated strikes, reconnaissance, and SEAD (Suppression of Enemy Air Defences).

Su-57D

Russia’s UAC announced on May 19, 2026, that the Su-57D — a two-seat, multifunctional, fifth-generation fighter — had commenced flight testing. The Su-57D is now the third stealth fighter with a twin-seat variant.

Circumstantial evidence suggests that Russia provisioned for a twin-seat variant of the Su-57 from the start of the aircraft’s development.

Reliable Russian social media recently reported that the Su-57D “was converted from the already existing 055 aircraft in the shortest possible time.”

“The Indians wanted such an aircraft, and we customized it for them.”

Converting an existing single-seat airframe into a twin-seater in a short time would not have been possible had Sukhoi not designed the aircraft for such a conversion.

The most likely reason Sukhoi did not develop a twin-seat variant earlier was that the Russian Aerospace Forces never projected the need for one.

However, over the past couple of years, Sukhoi has completed development and operational testing of the S-70 Okhotnik stealth combat drone. Su-57 fighters have successfully carried out operational Su-57 + S-70 MUM-T missions in Ukraine.

The need for a twin-seat variant of the Su-57 has now been firmly established, and Russia’s Ministry of Defense has already ordered a batch of the twin-seaters.

HAL Likely to Offer a Customized Su-57D Variant

Russia has offered to help HAL build a customized variant of the Su-57D for the IAF. The offer reportedly involves ToT and industrial participation, including joint-venture production of components in India, licensed assembly, MRO facilities, and possible avionics customization.

If Rosoboronexport and HAL successfully negotiate the technological and financial terms of their collaboration, HAL is likely to offer the customized Su-57D variant to the IAF.

The HAL–Rosoboronexport tie-up is unlikely to be derailed by any CAATSA sanctions because U.S. leverage over HAL is limited. Any U.S. move to stop the supply of GE F404 or F414 engines to HAL is likely to hurt Boeing as much as it hurts India. From India’s perspective, such sanctions now would be preferable to sanctions imposed when the LCA Mk-2 and AMCA programs are approaching maturity and serial production.