(DEFENCE SECURITY ASIA) — In a striking development amid long-standing concerns over production setbacks, the Russian Aerospace Forces have reportedly taken delivery of two newly built Su-57 Felon stealth fighter —an indication that the Kremlin is still pushing ahead with its fifth-generation ambitions despite formidable headwinds.
The latest units, marked with tail numbers “25” and “26,” are believed to be the first Su-57s delivered to the Russian Air Force in 2025, representing a symbolic continuation of a program often dogged by delays and technical obstacles.
Images of the two aircraft appeared on social media on April 10, depicting the fighter jets being transferred to an undisclosed Russian air base under tight secrecy, fuelling speculation about their readiness and deployment status.
Notably, Russian authorities and the state defence conglomerate ROSTEC have yet to issue any formal acknowledgment of the delivery, raising questions across the global defence community about the authenticity and operational status of these airframes.
However, the aircraft’s previously unseen serial numbers suggest they are freshly manufactured units, likely completed in recent weeks at the Komsomolsk-on-Amur Aircraft Plant (KnAAPO), Russia’s principal production facility for the Su-57.
While neither the United Aircraft Corporation (UAC) nor the Russian Ministry of Defence has commented publicly, sources familiar with the matter indicate these airframes were recently finalized and quietly relocated, perhaps to obscure ongoing production challenges.
The Su-57 program remains encumbered by structural inefficiencies, high development costs, and logistical hurdles, limiting the scale and pace at which the aircraft can be fielded by the Russian military.
Though the Su-57 was officially inducted into service in 2020, as of early 2025, fewer than 20 aircraft are believed to be in active operational status—far below Moscow’s original procurement goal of 76 units by 2027.
The program’s sluggish progress is primarily attributed to a painfully slow production rate, exacerbated by overlapping industrial demands, technological shortfalls, and persistent geopolitical constraints.
One of the most significant impediments remains the effect of Western sanctions—especially those intensified following the 2022 invasion of Ukraine—which have severely curtailed Russia’s access to foreign-manufactured avionics, AESA radars, high-performance sensors, and advanced electronic warfare systems.
This forced Russia to fall back on domestically developed substitutes, many of which are still in the prototype phase or fall short of meeting fifth-generation operational benchmarks, creating a performance gap that remains unresolved.
Simultaneously, Russia’s broader defence-industrial base is under severe pressure, as resources are funneled toward high-demand wartime systems such as drones, cruise missiles, and legacy fighter platforms for use in the ongoing Ukraine conflict.
At the heart of this constraint lies KnAAPO, the primary assembly plant for the Su-57, which is also responsible for producing Su-35 multirole fighters and the next-generation Su-75 “Checkmate” prototype, resulting in severe strain on technical personnel and production throughput.
Compounding these structural challenges is the Su-57’s high unit cost, which limits procurement even within Russia’s own defence budget and has proven a major stumbling block for export ambitions.
India’s withdrawal from the co-development Fifth Generation Fighter Aircraft (FGFA) program in 2018, coupled with a lack of international orders since, underscores persistent concerns over the Su-57’s cost-efficiency, combat credibility, and long-term viability.
Operationally, integration remains incomplete, with Russia’s vision of incorporating the Su-57 into a network-centric battlefield environment—particularly alongside the stealthy S-70 Okhotnik-B unmanned combat aerial vehicle—still in the early stages of flight testing and systems development.
Until these operational linkages are fully realized and production bottlenecks are resolved, the Su-57 will remain a platform with high theoretical potential but limited real-world presence.
In 2024, the Russian Air Force reportedly received three batches of Su-57 fighters, with the final delivery registered in December, marking incremental but inconsistent progress.
All Su-57 airframes are manufactured at UAC’s Komsomolsk-on-Amur facility in Russia’s Far East, a site that has become a focal point of Russia’s advanced aviation capabilities and one of its most closely guarded industrial assets.
The most recent images and delivery reports surfaced roughly two months after KnAAPO Director Yuri Kondratyev announced that a new variant of the Su-57 would be delivered in 2025, raising hopes of a more mature iteration of the aircraft entering service.
Although no detailed technical enhancements were confirmed, speculation has grown that the new variant will feature Russia’s long-awaited second-stage engine: the AL-51F1, also known as “Product 30.”
Earlier this year, UAC CEO Vadim Badekha reaffirmed that the Su-57 platform was designed with longevity and adaptability in mind.
“The Su-57 platform was created with a lifespan of 40 to 50 years. It features an open architecture, allowing for the integration of a wide range of technologies with minimal changes to the baseline design,” Badekha said.
“Integration of the Su-57 with unmanned aerial vehicles will become the core of future combat systems. In the coming years, new features will be gradually introduced into serial production Su-57s under the ongoing modernization program,” he added.