According to the Defense Acquisition Program Administration (DAPA), the fourth prototype flew for 34 minutes on February 20 at Sacheon, the home base of domestic aircraft maker Korea Aerospace Industries (KAI). The fighter jet took off from the airbase at 11:19 a.m. (0219 GMT) and reached an altitude of 15,000 feet (4.5 kilometers). Unlike previous prototypes, the new aircraft has two seats in its front and rear.
By June 2026, the fourth prototype will be used to check the impact on the aircraft caused by the difference in shape from the single-seat types. It will also be used to demonstrate active electronically scanned array (AESA) radars capable of detecting a target object and collecting various information such as distance and speed to the target area.
Because one more cockpit was added near the front part of the aircraft's main body, the space of the internal fuel tank was slightly changed, DAPA said, adding that the rest of the space is relatively similar to the conventional types. In the first half of 2023, the agency will demonstrate the fifth and sixth aircraft. The sixth prototype will be built as a two-seater type.
After the first KF-21's flight in July 2022, some 110 test flights were carried out. Through the KF-21 project, South Korea hopes to manufacture 120 fighter jets that would replace the country's aging fleet of U.S.-made F-4 and F-5 fighters. According to specifications outlined by KAI, the fighter's maximum speed is Mach 1.81 with its range standing at 2,900 kilometers. About 8.8 trillion won ($6.7 billion) would be injected by 2028.