Advanced IFF Integration for Tactical Fighter Aircraft

BAE Systems has been awarded an $11 million contract from Korea Aerospace Industries to integrate the AN/APX-127(V)1 Combined Interrogator Transponder on the KF-21 Boramae fighter aircraft, strengthening combat identification capabilities in contested airspace.

Enhancing combat identification on the KF-21
The contract covers the integration of the AN/APX-127(V)1 Combined Interrogator Transponder (CIT), a tactical aircraft IFF system designed to support reliable identification of friendly, allied, and potential hostile forces. Accurate identification is a critical requirement in modern air operations, where dense, multi-domain environments increase the risk of misidentification and fratricide.

By upgrading the KF-21 with a next-generation CIT, the program aims to improve decision-making speed and situational awareness during air superiority and joint operations.

Open architecture and future readiness
The AN/APX-127(V)1 is built on an open-system architecture, allowing software-based upgrades without extensive hardware changes. This approach reduces long-term sustainment risk and supports incremental capability growth as mission requirements, cryptographic standards, and threat environments evolve.

The system is designed to meet current and emerging requirements for secure communications, including resistance to jamming and enhanced cybersecurity resilience. Increased processing capacity also addresses obsolescence concerns while enabling future functionality.

Certification and interoperability standards
The system is Mark XIIB IFF certified and supports Mode S and Mode 5, enabling encrypted and secure identification in compliance with NATO and allied standards. These modes are central to coalition interoperability, ensuring that aircraft can operate seamlessly with U.S. and partner forces during combined missions.

Additional receive channels enhance situational awareness by supporting passive acquisition of Mode 5 Level 2 signals and Automatic Dependent Surveillance–Broadcast (ADS-B In). This allows the aircraft to detect and identify friendly platforms without actively interrogating them, a capability that is particularly valuable in complex and contested operational environments.

Integration and platform continuity
The AN/APX-127(V)1 shares the same form factor as the AN/APX-126(V) CIT currently used on the KF-21, enabling a drop-in replacement. This compatibility simplifies integration and certification while minimizing aircraft modification requirements.

Work on the system will be carried out at BAE Systems facilities in Greenlawn, New York, and Austin, Texas. Delivery of the CIT units to Korea Aerospace Industries for aircraft integration and certification is planned for 2026.

Broader context in defense avionics
IFF systems remain a foundational element of air combat and air defense architectures, particularly as fifth-generation platforms operate in increasingly networked and coalition-centric scenarios. The integration of the AN/APX-127(V)1 on the KF-21 reflects a broader shift toward software-upgradable, standards-based avionics that can adapt to evolving operational and interoperability demands.

With decades of experience in combat identification technologies, BAE Systems’ latest CIT implementation illustrates how modern IFF architectures are being aligned with future air combat requirements while maintaining continuity with existing platforms and allied systems.