Indonesia’s second test pilot flies KF-21 Fighter front seat in South Korea validating stability and control
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The Indonesian Air Force said a second TNI-AU test pilot flew from the front seat of a twin-seat KF-21 Boramae prototype in South Korea on Sept. 30, 2025, with KAI test pilot Koh Hwi Seok in the rear; the one-hour sortie stayed between 10,000–20,000 ft and focused on performance and Stability & Control points.
The Indonesian Air Force confirmed on Oct. 2, 2025, that a second TNI-AU test pilot completed his first front-seat mission in a twin-seat KF-21 prototype at Sacheon, South Korea, on Sept. 30 with KAI test pilot Koh Hwi Seok in the rear cockpit. The one-hour sortie held 10,000–20,000 ft validated performance points and Stability & Control items, part of a multiyear Indonesia–Korea flight-test collaboration that already saw the first Indonesian front-seat sortie on June 27, 2025. Indonesia’s participation now spans hands-on flight testing, mixed crews, shared procedures, and technology transfer, aligning with the KF-21’s incremental blocks approach: air-to-air first, then progressively adding air-to-surface stores.Follow Army Recognition on Google News at this link
The KF-21 Boramae is a twin-engine multirole fighter of the “4.5-generation,” designed first for air superiority and then for precision strike. (Picture source: TNI AU)
Formerly known as KF-X, the KF-21 is positioned as a twin-engine multirole fighter with an initial emphasis on air superiority. On the twin-seat airframe used for trials, the tandem arrangement splits tasks: the mission pilot and the systems pilot can share workload and monitoring, which supports test plan progress. Propulsion relies on two F414-family turbofans produced under license in Korea, a pragmatic choice to secure timelines and support. The avionics suite centers on a domestically developed AESA radar within a digital architecture designed for growth. External hardpoints provide flexibility across proven munitions while keeping options open for later, lower-observability integrations.
On air-to-air weapons, the roadmap remains straightforward. At short range, a modern infrared-guided missile supplies the agility required for close-in combat and off-boresight engagements, relevant to peacetime air policing and short-notice interceptions. At long range, integration of a contemporary BVR missile enables beyond-visual-range shots, paired with the AESA radar for multi-target detection and tracking. Using available weapons for early blocks aims to limit risk and field a credible operational capability before moving to more complex integrations over time.
On the acquisitions side, Jakarta clarified its path in June 2025 during Indo Defence by concluding with Seoul a revised agreement that provides for the delivery of 48 KF-21s while preserving Indonesian industrial participation. The compromise also reduces Indonesia’s contribution to development costs to 600 billion won, about 440 million dollars, according to Korean official announcements. A total purchase price was not disclosed; the announcement focused on cost-sharing and the production framework. The policy objective is to secure a national fleet of 48 aircraft, maintain access to technology transfer, and spread the budget load. For Jakarta, the operational interest lies in gradually standardizing the air-superiority fleet and raising local competencies through joint work with Korean industry.
The September 30 flight illustrates the mechanics of a methodical test program. At 10,000 and then 20,000 feet, the Stability & Control campaign maps the airframe’s response and flight-control laws from takeoff to cruise, including attitude and speed transitions. Koh Hwi Seok’s role in the rear seat also explains the approach: a mixed crew with the manufacturer collecting data and the customer pilot providing feedback that informs the debrief. This pairing has immediate value for test safety and a downstream benefit for training Indonesian crews who will follow.
The KF-21 is intended to hold the line in air policing and then broaden its mission set. The AESA radar and digital mission management enable data fusion, engagement of multiple tracks, and execution of long-range firing profiles. The twin-engine airframe, combined with aerial refueling already evaluated by South Korean teams, should support longer patrols useful for maritime surveillance across large areas and for offset interception lines. The twin-seater in development is not only a training tool; on complex missions, a second crew member can manage electronic warfare, data links, or, in due course, air-to-surface targeting, smoothing the transition from air-to-air-focused early blocks to denser multirole profiles.
Indonesian authorities also frame technology transfer as an explicit objective, alongside the development of human capital in the military aerospace sector. The official formula is expressed by the acronym AMPUH Adaptif, Modern, Profesional, Unggul, Humanis, which sets an institutional ambition and a framework for training crews and technicians able to absorb a new generation of combat capability.
This dynamic has industrial and political dimensions. For Seoul, the KF-21 is intended to occupy a price-capability band that attracts partners without the heaviest export restrictions. For Jakarta, participation in IF-X provides a path toward greater autonomy with know-how spillovers and defined roles in the technical chain. The front-seat flight by Colonel Sugiyanto fits this logic of tangible returns: a measured test, data collected, an Indonesian pilot at the controls, and visible cooperation. On May 16, 2023, the same officer had already flown in the KF-21’s rear seat, the first appearance of a foreign pilot on board. The current sequence extends that trajectory, marking an additional step in Indonesian responsibility both in the cockpit and in preparations for the next phases.
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The Indonesian Air Force said a second TNI-AU test pilot flew from the front seat of a twin-seat KF-21 Boramae prototype in South Korea on Sept. 30, 2025, with KAI test pilot Koh Hwi Seok in the rear; the one-hour sortie stayed between 10,000–20,000 ft and focused on performance and Stability & Control points.
The Indonesian Air Force confirmed on Oct. 2, 2025, that a second TNI-AU test pilot completed his first front-seat mission in a twin-seat KF-21 prototype at Sacheon, South Korea, on Sept. 30 with KAI test pilot Koh Hwi Seok in the rear cockpit. The one-hour sortie held 10,000–20,000 ft validated performance points and Stability & Control items, part of a multiyear Indonesia–Korea flight-test collaboration that already saw the first Indonesian front-seat sortie on June 27, 2025. Indonesia’s participation now spans hands-on flight testing, mixed crews, shared procedures, and technology transfer, aligning with the KF-21’s incremental blocks approach: air-to-air first, then progressively adding air-to-surface stores.
Follow Army Recognition on Google News at this link
The KF-21 Boramae is a twin-engine multirole fighter of the “4.5-generation,” designed first for air superiority and then for precision strike. (Picture source: TNI AU)
Formerly known as KF-X, the KF-21 is positioned as a twin-engine multirole fighter with an initial emphasis on air superiority. On the twin-seat airframe used for trials, the tandem arrangement splits tasks: the mission pilot and the systems pilot can share workload and monitoring, which supports test plan progress. Propulsion relies on two F414-family turbofans produced under license in Korea, a pragmatic choice to secure timelines and support. The avionics suite centers on a domestically developed AESA radar within a digital architecture designed for growth. External hardpoints provide flexibility across proven munitions while keeping options open for later, lower-observability integrations.
On air-to-air weapons, the roadmap remains straightforward. At short range, a modern infrared-guided missile supplies the agility required for close-in combat and off-boresight engagements, relevant to peacetime air policing and short-notice interceptions. At long range, integration of a contemporary BVR missile enables beyond-visual-range shots, paired with the AESA radar for multi-target detection and tracking. Using available weapons for early blocks aims to limit risk and field a credible operational capability before moving to more complex integrations over time.
On the acquisitions side, Jakarta clarified its path in June 2025 during Indo Defence by concluding with Seoul a revised agreement that provides for the delivery of 48 KF-21s while preserving Indonesian industrial participation. The compromise also reduces Indonesia’s contribution to development costs to 600 billion won, about 440 million dollars, according to Korean official announcements. A total purchase price was not disclosed; the announcement focused on cost-sharing and the production framework. The policy objective is to secure a national fleet of 48 aircraft, maintain access to technology transfer, and spread the budget load. For Jakarta, the operational interest lies in gradually standardizing the air-superiority fleet and raising local competencies through joint work with Korean industry.
The September 30 flight illustrates the mechanics of a methodical test program. At 10,000 and then 20,000 feet, the Stability & Control campaign maps the airframe’s response and flight-control laws from takeoff to cruise, including attitude and speed transitions. Koh Hwi Seok’s role in the rear seat also explains the approach: a mixed crew with the manufacturer collecting data and the customer pilot providing feedback that informs the debrief. This pairing has immediate value for test safety and a downstream benefit for training Indonesian crews who will follow.
The KF-21 is intended to hold the line in air policing and then broaden its mission set. The AESA radar and digital mission management enable data fusion, engagement of multiple tracks, and execution of long-range firing profiles. The twin-engine airframe, combined with aerial refueling already evaluated by South Korean teams, should support longer patrols useful for maritime surveillance across large areas and for offset interception lines. The twin-seater in development is not only a training tool; on complex missions, a second crew member can manage electronic warfare, data links, or, in due course, air-to-surface targeting, smoothing the transition from air-to-air-focused early blocks to denser multirole profiles.
Indonesian authorities also frame technology transfer as an explicit objective, alongside the development of human capital in the military aerospace sector. The official formula is expressed by the acronym AMPUH Adaptif, Modern, Profesional, Unggul, Humanis, which sets an institutional ambition and a framework for training crews and technicians able to absorb a new generation of combat capability.
This dynamic has industrial and political dimensions. For Seoul, the KF-21 is intended to occupy a price-capability band that attracts partners without the heaviest export restrictions. For Jakarta, participation in IF-X provides a path toward greater autonomy with know-how spillovers and defined roles in the technical chain. The front-seat flight by Colonel Sugiyanto fits this logic of tangible returns: a measured test, data collected, an Indonesian pilot at the controls, and visible cooperation. On May 16, 2023, the same officer had already flown in the KF-21’s rear seat, the first appearance of a foreign pilot on board. The current sequence extends that trajectory, marking an additional step in Indonesian responsibility both in the cockpit and in preparations for the next phases.
