[Yang Nak-gyu's Defence Club] KF-21 Radar Equipped Flight

Completed AESA Radar Performance Verification and First Installation
KF-21 Supersonic Flight Also Validates the Fighter's Eye

The Korean Fighter Jet (KF-21) equipped with an Active Electronically Scanned Array (AESA) radar, known as the "eyes of the fighter jet," completed its first test flight.

According to the Defense Acquisition Program Administration (DAPA) on the 4th, the KF-21 prototype No. 3 took off from Sacheon Airfield at 10 a.m., flew at a maximum speed of 330 KCAS (approximately 610 km/h) at an altitude of 30,000 feet, and landed at 11:24 a.m. Major Lee Su-beom of the Air Force was at the controls.

[Image source=Yonhap News]

The AESA radar, installed on the latest fighter jets, uses semiconductor transmit-receive modules with Monolithic Microwave Integrated Circuits (MMIC) to adjust the phase and amplitude of signals to detect and track targets, earning it the nickname "the eyes" or "the brain" of the fighter jet. Before being installed on the KF-21, the AESA radar underwent development test evaluations from last November until last month on a test aircraft modified from a B-737 to verify its required performance. During the development test evaluations, the AESA radar conducted a total of 18 flight tests across 25 air-to-air mode test items, confirming that it met all required performance and development goals.

The KF-21 prototype No. 3 (single-seat), equipped with the AESA radar, successfully completed its first flight on January 5 of this year.

DAPA plans to conduct about 90 flights by February 2026 to perform development and operational test evaluations on 34 items, including maximum detection and tracking range and tracking accuracy in air-to-air mode, to verify whether the operational performance, military suitability, and practical support elements for weaponization are met.

The KF-21 achieved its maiden flight on July 19 last year and broke the sound barrier on the 17th of last month. DAPA is pushing forward with the development schedule aiming to complete approximately 2,000 test flights by February 2026. According to Korea Aerospace Industries (KAI), the KF-21 is equipped with twin engines and stealth technology. It measures 16.9 meters in length, 11.2 meters in wingspan, and 4.7 meters in height, making it larger than the F-16 fighter jet and similar in size to the F-18 fighter jet. Its maximum speed is Mach 1.81 (2,200 km/h), with a range of 2,900 km and a weapons payload capacity of 7.7 tons.