The KF-21 prototypes successfully carry out the first weapons flight tests.

South Korea successfully conducted the first tests of two prototypes of its domestically-made KF-21 fighter on Tuesday, the state arms procurement agency said, to test their combat capabilities.

According to the Air Force Acquisition Program Administration, the prototypes underwent separate tests over the waters off the country’s southern coast after taking off from the Air Force’s 3rd Flight Training Wing in Sacheon, 300 kilometers south of Seoul—defense (DAPA).

The second and third prototypes of the KF-21 were mobilized for testing. Currently, four prototypes have participated in flight tests under a plan to use a total of six for the general test plan until 2026.

The second prototype test was designed to see if a Meteor medium-range air-to-air test missile could separate from the reactor without any problem. Testing on the other prototype consisted of firing about 100 rounds from a machine gun mounted on the third prototype.

DAPA said the tests examined possible changes to the airframe, engine, and aerodynamic characteristics of the plane during the operation of the weapons in order to ensure its operational stability and safety.

With the latest tests, DAPA said the KF-21 has taken “another step” to become a “full fighter” to protect the country’s airspace. Launched in 2015, the 8.8 trillion won ($6.8 billion) KF-21 project aims to develop a supersonic fighter to replace South Korea’s aging F-4 and F-5 jets.

South Korea has conducted more than 150 test flights with the four KF-21 prototypes since the plane’s maiden flight in July last year. The agency plans to start the test flights of two other prototypes in the first half of the year, with a plan to carry out some 2,000 flights in total until February 2026.

DAPA plans to conduct tests in all flight areas, such as at low and high altitudes and low speeds, and more weapons tests, including short-range air-to-air missiles. It also plans to operate the aircraft with medium- and long-term indigenous weapons.