South Korea Successfully Conducts Maiden Flight Of Third KF-21 Fighter Jet Prototype; Now Aims To Go Supersonic!

On January 5, the third prototype of South Korea’s homegrown fighter, the KF-21 Boramae, completed its first flight, indicating significant advancements in the nation’s high-profile jet development program. 

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The prototype flew for 37 minutes after taking off from the Air Force’s 3rd Flying Training Wing in Sacheon, roughly 300 kilometers south of Seoul, according to the Defense Acquisition Program Administration (DAPA), South Korea’s procurement agency. 

The first prototype carried out its maiden flight on July 19, 2022. Later, the second prototype conducted its first flight in November 2022. 

In contrast to earlier versions, the third prototype is outfitted with the technologies required for tests on the fighter’s speed and loadable weight, paving the way for additional fighter capabilities tests, DAPA said.

Before this, the first prototype was only used for the speed test. The second prototype was employed to evaluate the plane’s structural load capacity. 

The agency stated that it intends to begin testing three more prototypes in stages during the first half of this year, with a total of 2,000 tests planned by February 2026. 

The long-running KF-X program, a collaborative development between South Korea and Indonesia, produced the KF-21 Boramae. Seoul has 80% of the shares in the project, while Indonesia holds 20%.

The 8.8 trillion won ($6.9 billion) KF-21 project, which was started in 2015, aims to build a supersonic fighter to replace South Korea’s outdated fleet of F-4 and F-5 fighters. The 4.5-generation fighter will enter the mass-production stage in 2026. The ROKAF intends to procure 120 KF-21 aircraft by 2032.


DAPA previously said that the KF-21 is the first fighter aircraft produced using local technology, demonstrating South Korea’s ability to produce fighter aircraft independently. Additionally, it will serve as a springboard for improving fighter aircraft and using locally produced weapons.

Even though just 65% of the KF-21’s components are made in South Korea, the flight tests of prototypes represent a noteworthy accomplishment for a nation with a brief history of aircraft production.

The United States, Russia, China, Japan, France, Sweden, and an alliance of four European nations—the United Kingdom, Germany, Italy, and Spain—are the only other nations to have produced and flown advanced supersonic jet fighters. 

The KF-21 will enhance South Korea’s aerial offensive and defensive capabilities. Given the poor condition of North Korea’s aging air force jets, the KF-21 can easily outperform them.

In the future, the (South Korean) air force will be equipped with a mix of F-35s for strike operations and KF-21s for air defense. Experts believe this framework will make good use of the F-35, which is better designed for ground attacks, while the KF-21 is designed for air-to-air missions.

Korea Seeks To Achieve Supersonic Speeds

Seoul is now aiming to test its homegrown KF-21 fighter at supersonic speeds this month if weather permits, Yonhap News Agency reported on January 5. The test would represent a significant step forward in the high-profile warplane development effort. 

Achieving supersonic capabilities is a crucial aspect of the development efforts led by its manufacturer, Korea Aerospace Industries Ltd. (KAI). The test is necessary to ensure that critical functions, such as avionics, operate properly regardless of flight speed. 

The manufacturer intends to undertake the test (for supersonic speeds) sometime in January. However, a source told the Yonhap news agency that the exact date could not be disclosed because it may be postponed due to weather conditions. 

The development comes at a time when tensions between North Korea and South Korea are at an all-time high. On December 26, Pyongyang launched five drones across the Military Demarcation Line, separating the two Koreas. 

KF-21: Republic of South Korea Air Force

A military official disclosed on January 5 that a North Korean drone briefly crossed a 3.7-kilometer-radius no-fly zone over President Yoon Suk Yeol’s office in Seoul last month. 

Meanwhile, the South Korean military carried out live-fire air defense maneuvers on Thursday afternoon under a scenario of small enemy drone infiltrations. 

The exercises featured about 50 aircraft, including KA-1 light attack planes and 500MD helicopters with personnel carrying drone jammer guns. The military conducted counter-drone drills without a live-fire segment on December 29, days after North Korea’s drone intrusions. 

Drone invasions have exposed South Korea’s inadequacy in terms of the ability to find, track, and shoot down such UAVs. According to the defense ministry, the North Korean drones, in particular, flew on improper trajectories, abruptly changing flying speed and height.