Having successfully launched a satellite delivery vehicle earlier last week, South Korea’s indigenous aerospace and arms industry is on a surge. Next on the runway: The KF-21 Boramae (”Falcon”) 4.5-generation fighter is gearing up for take-off.

According to Asia Military Review, citing Kookang Ilbo, the official newspaper of South Korea’s Ministry of Defence, the jet has completed 50% of its overall test program and 95% of all ground testing requirements ahead of its maiden flight, scheduled for July.

The US government defines 4.5-generation aircraft as having advanced capabilities, including active electronically scanned array (AESA) radar, high-capacity data links, enhanced avionics and the capability to deploy current and reasonably foreseeable advanced armaments.

A 4.5-generation fighter is thus not quite up to the standards of fifth-generation stealth fighters like the F-22 and the F-35. Examples of 4.5-generation warbirds include the US F-15E/EX Strike Eagle, the Chinese Chengdu J-10C and Russia’s Sukhoi Su-35.

With the US sensitive about sharing advanced technologies, the KF-21 may be part of Seoul’s efforts to reduce its reliance on foreign arms while also positioning itself as a major manufacturer and exporter of high-end weaponry.

In the latter sense, the KF-21 is a flagship project. Potential buyers are likely to be those nations that seek leading-edge fighters at more reasonable costs than top-tier Western models.

South Korea co-produces the KF-21 with Indonesia, with Yonhap reporting that Indonesia has promised to shoulder 20% of the project’s cost of US$7.6 billion.

Earlier, payment issues on Indonesia’s part threatened to derail its participation in the project. However, The Korea Herald reports that South Korea and Indonesia finalized payment terms last November.

“Indonesia will make payments over the next five years until 2026, and 30% of that would be in-kind transfers,” according to South Korea’s Defence Acquisition Program Administration.

At the same time, there is a possibility that South Korea’s long time ally the US may become reluctant to share critical military technologies as Seoul pushes ever-more aggressively into export markets.

In a striking 2013 article, Foreign Policy asked whether South Korea may be secretly stealing US military technology, alleging that Korean manufacturers are known for making upgraded knockoffs of US military equipment.

With regards to technology-sharing agreements, the article quoted an unnamed retired former government official who worked in Seoul as saying, “They are very good at taking full advantage of any loopholes with any type of agreement.”

Foreign Policy also noted that these practices could undercut US arms sales and leak sensitive US technologies. Perhaps. But even a cursory visual examination makes clear that the KF-21 is strikingly similar to the US-made F-35.

South Korea may be positioning the KF-21 as an affordable alternative to Western 4.5- generation fighters on the international market.

According to The National Interest, the KF-21’s $65 million estimated per-unit price puts it above cut-rate light fighters such as the FA-50 – the fighter version of the T-50 jet trainer developed by Korea Aerospace Industries with Lockheed Martin – but two-thirds below the price of advanced Western fighters like the Rafale and Typhoon.

The 19fortyfive military publication notes that the KF-21 will cost half as much to operate as the F-35 that South Korea currently uses. That makes it a potential option for states wishing to acquire advanced air superiority aircraft at a fraction of the cost of Western models.

Operationally, South Korea envisages its KF-21 flying alongside its existing fleet of F-15Ks, F-35As and allied US assets.

In an article by the Korea Institute of Defence Analysis quoted by the Royal Aeronautical Society, Brigadier-General (Retired) Kwang Sun-jung said that ROKAF doctrine is based on combined ROK-US operations, with the integration of communications systems, combined tactical data communications and weapons commonality.

It is possible that South Korea is building an indigenous high-low fighter configuration for its air force.

If so, the KF-21 is the high-end component that will operate in defended airspace over North Korea. The FA-50 light combat aircraft is the low-end component that will operate in contested airspace over South Korean territory. The KF-21 represents a serious qualitative overmatch to North Korea’s obsolete and underfunded air force.

“Our government will strengthen capabilities to better implement the US extended deterrence and will dramatically enhance response capabilities of the Republic of Korea military to deter North Korea’s nuclear and missile threats,” said South Korean Defence Minister Lee Jong-sup, as quoted in the National Interest.

According to the International Institute of Strategic Studies (IISS), North Korea operates a sizable inventory of more than 400 fighters, 80 light bombers, and more than 200 transports.

However, the fighter force consists of obsolete Soviet-era designs and Chinese copies such as the MiG-17/J-5, MiG 19/J-6, and multiple variants of the MiG-21, MiG-23, and MiG-29. In addition, IISS states that North Korea cannot pay for fuel and maintenance, while its pilots receive less than 30 hours of flight time annually.

As noted by Asia Military Review, Korea Aerospace Industries (KAI) is currently conducting ground testing with six KF-21 prototypes and two spares. Low-rate production is aimed to start in 2026 and full-rate production in 2028. Seoul plans to deploy 40 KF-21s by 2028, with 120 by 2032, which if accomplished would make South Korea the world’s eighth nation to develop an advanced supersonic fighter with its own technology, the Korea Times said in an article.

KAI, the main contractor for the KF-21, mentions that the type will replace the Republic of Korea Air Force’s (ROKAF) aging F-4 and F-5 third-generation fighters. It describes the KF-21 Boramae as “a fighter aircraft developed to maintain the operational capability of the ROKAF and satisfy the future operation concept … as a multi-role fighter jet which features enhanced survivability, combined/joint operations, sustainment and logistics support system, air superiority, and ground precision strike.”

According to the Korea Times, 719 South Korean businesses are involved in the project, with 65% of the KF-21’s 30,000 parts made in South Korea, with plans to increase this percentage.

Some of these critical parts were identified by Defence News, which include the KF-21’s AESA radar, infrared (IR) search-and-track pod, electronic warfare suite and electro-optical targeting pod. KAI says the KF-21 has a maximum thrust of 19,950 kilograms, 2,850-kilometer ferry range, 2,250km/h top speed, a 7,700kg maximum payload and a 25,580kg maximum take off weight. Defence News reports that two US-made General Electric F414 engines power the jet.

The KF-21 is designed to be compatible with Western and South Korean-made armaments. It can carry 7.6 tons of missiles, bombs, and external fuel tanks distributed between the fuselage and wings, according to an Aviacionline report.

The Royal Aeronautical Society notes that the KF-21 does not have an internal weapons bay; instead, it will carry four MBDA Meteor beyond-visual-range (BVR) missiles in semi-recessed fuselage stations.

It will also carry Diehl Defence IRIS-T IR-guided missiles for close range strikes. The KF-21 also features a M61A2 20mm General Dynamics Gatling gun with 480 rounds and a 6,000 shot-per-minute rate of fire.

Defence website 19fortyfive specifies the KF-21’s possible air-to-ground armaments, which include the GBU-12 Paveway-III and GBU-54 laser-guided bombs, the GPS-guided JDAM and small diameter bomb, and CBU-105 cluster bomb.

For standoff attacks, the KF-21 may employ the HARM anti-radiation missile against enemy radars, the bunker-busting Swedish-German Taurus KEPD-350 cruise missile or an indigenous cruise missile.

Last April, Janes reported that South Korea will open a “smart factory” to ramp up production of the KF-21, investing $88 million over the next five years to establish a “smart manufacturing system based on Fourth Industrial Revolution digital technologies including artificial intelligence and big data analytics.”