The Block I production phase covers the first batch of 20 aircraft, contracted in mid-2024 under a deal worth approximately KRW 1.96 trillion (about USD 1.4 billion).This latest update was disclosed through a video released on December 31, 2025, on KAI’s official YouTube channel, which revisited the KF-21 production floor roughly nine months after it was first opened to the public.

The footage provides rare, close-up views of airframe assembly now underway as the program accelerates toward operational service. According to industry and government disclosures, Korea Aerospace Industries (KAI) began final assembly of the first production aircraft at its Sacheon facility in May, marking the transition from prototype testing to serial output.

The milestone was attended by officials from South Korea’s defense authorities and the Republic of Korea Air Force (ROKAF), underscoring the aircraft’s strategic importance to Seoul’s future airpower.

The Block I production phase covers the first batch of 20 aircraft, contracted in mid-2024 under a deal worth approximately KRW 1.96 trillion (about USD 1.4 billion).

These jets are expected to form the initial operational backbone of the fleet, with deliveries scheduled to begin following final assembly, ground testing, and acceptance flights.

According to a South Korean defense-industry source, a formal ceremony for the first mass-production KF-21 aircraft is planned for March next year. The event is expected to serve as a symbolic milestone, highlighting the program’s transition from development into full-scale manufacturing and signaling readiness for imminent service entry.

Beyond factory visuals, the December 31 video features interviews with the production program manager and a test pilot, offering a candid assessment of the challenges facing the program.

The production lead acknowledged that global supply-chain disruptions have complicated the procurement of several key components, creating bottlenecks in parts availability and adding pressure to production schedules.

Coordinating domestic and overseas suppliers while meeting certification and quality requirements has proven particularly demanding during the shift to serial manufacturing.

Despite these constraints, KAI said mitigation measures—including alternative sourcing, closer supplier coordination, and phased production planning—are being implemented to keep deliveries on track.

The test pilot noted that continuous feedback from the flight-test campaign is being rapidly incorporated into production aircraft, improving system maturity as the fighter approaches operational service.

Powered by twin F414-class engines and designed as a high-end multirole platform, the KF-21 Boramae is intended to bridge legacy fourth-generation fighters and more costly fifth-generation stealth aircraft.

For South Korea, the program represents not only a leap in combat capability but also a cornerstone of national defense-industrial autonomy and long-term export ambitions.

With final assembly underway, supply-chain challenges openly acknowledged, and a first production-aircraft ceremony expected in March, the KF-21 has clearly crossed the threshold from development effort to a production fighter on the verge of operational service.

K-DEFENSE NEWS | Strategic Analysis Desk

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