Pushing the envelope: KF-21 achieves additional milestones

The second KAI KF-21 fighter aircraft prototype launches a mid-range Meteor air-to-air missile during the aircraft's armament testing flight on 28 March 2023. (DAPA)

In a span of six weeks, the Korea Aerospace Industries (KAI) KF-21 aircraft programme has progressed from adding a new twin-seat prototype for flight-testing to initiating weapons launching trials using earlier prototypes.

Since the KF-21's first flight in July 2022, four prototypes have conducted more than 150 flight tests, South Korea's Defense Acquisition Program Administration (DAPA) said in March 2023. The programme's pace shows that South Korea is expanding its assessments of the aircraft's broader capabilities.

The introduction of the fourth prototype is enabling DAPA to explore the flight-worthiness and stability of the two-seat design. In a video posted by KAI on 6 March, CJ Kim of the KF-21 project team said flight-testing of prototype No 4 will “determine what impact the two-seat design has on aerodynamics”.

According to DAPA, the fourth prototype conducted its first test flight on 20 February.

“As [a second] cockpit is added in the front fuselage, the internal fuel tank space is reduced. The front of prototype No 4 is slightly changed, but the rest of the aircraft has the same shape as the single seater. This initial flight tested the flight stability,” DAPA said.

“During the first flight, prototype No 4 flew at the altitude of 15,000 ft and at the speed of 200 kt,” DAPA told Janes .

According to the agency, this 34-minute first test flight was conducted with only one pilot onboard. “Prototype No 4 will undergo flight tests until June 2026, when system development is completed. The effect of the difference in shape from the single-seat type will be checked,” DAPA said.