KF-21 Boramae: 1 of 120 jets delivered to ROKAF

Korea Aerospace Industries handed over the first production KF-21 Boramae to the Republic of Korea Air Force on Sept. 22, Simple Flying reports. The air force has 120 of the jets on order. One has arrived.

The gap is the story. The F-4 Phantom IIs the KF-21 was bought to replace left service more than two years ago, and the F-5 Tiger IIs still flying are due out by the end of 2027.

Two fleets running out of time

The F-4E entered ROKAF service in September 1977, and 94 airframes followed over five decades, per Simple Flying. The last operational Phantoms were retired on June 7, 2024, after 55 years of continuous service, and the jets that flew that final mission had been active for roughly 45 years.

The F-5 line goes back further. The first F-5A/B Freedom Fighters arrived in 1965, upgraded F-5E/F Tiger IIs followed from the mid-1970s, and the newest airframes are KF-5E/F Jegong-ho variants built in South Korea in the 1980s. About 50 remain active, with fleet ages running from 40 to 61 years. Maintenance support is close to gone, and Air Force Chief of Staff General Son Seok-rak cut the F-5 retirement date from 2030 to the end of 2027.

What the new jet brings

Simple Flying reports the KF-21 carries an active electronically scanned array radar able to track dozens of targets at long range, replacing the mechanical radars of the legacy fleet, and it flies with weapons such as the Meteor missile. Its angular, low-observable shape reflects less radar energy than the F-4 and F-5 designs, and its two engines burn less fuel, which keeps it useful on long Pacific patrols.

KAI is pitching a further step, the KF-21EX Block III: radar-absorbent material, weapons carried internally instead of hung on the wings, and a digital combat computer that fuses sensor data and lets the pilot direct autonomous Collaborative Combat Aircraft. Simple Flying places the standard KF-21 at 4.5-generation level, alongside the Boeing F-15EX, the Eurofighter Typhoon Tranche 5 and the Dassault Rafale F4.

The Block III engine is meant to end reliance on American export approvals. It will not fly until 2040, per Simple Flying, which is why a mixed fleet looks like the route to 120 aircraft.

The price per jet

Block I, the air-superiority version, is listed at about $83 million, and the multirole Block II at about $112 million. Add $11.25 million for the General Electric F414 engines and the localized AESA radar, and a Block II ready for combat runs roughly $94 million to $112 million, per Simple Flying.

That is more than the F-15EX at about $95 million and the F-35A at about $85 million. Indonesia's proposed batch of 16 Block II jets was valued at about $2 billion, an average of $125 million each.

Part of the reason: the Defense Acquisition Program Administration limited the first Block I order to 40, MiGFLUG reported, which pushed Block II costs up nearly 30% as fixed startup costs such as tooling were spread over fewer aircraft. Marketing early in the program had put the KF-21 near $70 million, 19FortyFive reported. Defense-sector inflation, supply chain disruption and a weaker South Korean won added to the bill.

One jet down, 119 to go, and the F-5s leave in 2027 either way.

Where the exports stand

Indonesia, once the closest partner, has instead signed on as launch customer for Turkey's Kaan, and defaulted on its cost-sharing commitment. The Philippines is weighing 12 to 24 KF-21s after buying FA-50 light fighters, and Peru is in the same contest against the F-16 Block 70 and the Saab Gripen E. Malaysia is reviewing up to 30 aircraft for its Next-Generation Multi-Role Combat Aircraft program, replacing Su-30 Flankers and F/A-18 Hornets.

The United Arab Emirates is looking at a package of as many as 100 jets. After a January 2023 memorandum of understanding, the UAE and South Korea signed a framework agreement covering a KF-21 variant, local co-production and exports to third countries, per Simple Flying.

KAI still hopes Indonesia buys direct export models. The ROKAF flies the Boramae first, and the export order book depends on how that goes.

• F-4 Phantom II
• F-5 Tiger II
• KF-21 Boramae
• Korea Aerospace Industries
• ROKAF
• South Korea