STC and AMOC Approvals Issued for Bell 407 and Airbus AS350 5G-Resilient RA-4500 MK II Installations

FreeFlight Systems announced it has received FAA Supplemental Type Certificates (STCs) supporting installation of its RA-4500 MK II radar altimeter on the Bell 407 and Airbus AS350 helicopters. The FAA also issued corresponding Alternative Methods of Compliance (AMOCs), confirming the approved configurations meet the requirements of FAA AD 2023-11-07 for radio altimeter tolerance in the 5G C-band environment.

Radar altimeter performance remains a key focus for regulators, operators and MROs across the rotorcraft community. These approvals expand compliance options for two of the most widely operated light single-engine helicopter platforms, helping reduce uncertainty and simplify installation planning and compliance documentation for mixed fleets.

The RA-4500 MK II is part of FreeFlight Systems’ TERRAIN SERIES of 5G-Resilient radar altimeters and combines a modern digital design with advanced RF filtering to help rotorcraft operators maintain reliable, high-fidelity AGL radar altitude performance in today’s changing RF environment.

“The 5G era has made radar altimeter performance a front-and-center operational issue for rotorcraft operators, and the RA-4500 MK II reflects that reality,” said Anthony Rios, president of FreeFlight Systems. “Its all-new digital design provides rotorcraft operators with high-integrity radar altitude performance, including low-level operations and RF-dense environments. These new STCs align with our commitment to deliver retrofit-ready avionics that enhance safety and flight efficiency, with long-term reliability as requirements continue to evolve.”

Proven across helicopter fleets, the RA-4500 MK II is an installer-friendly, regulation-ready solution for Bell 407 and AS350 installations. FreeFlight provides a complete documentation package, including STC drawing data, Rotorcraft Flight Manual Supplement and the applicable AMOC letters, to support installation, logbook entries and compliance documentation.

FreeFlight Systems also noted that as FAA guidance related to 5G and radar altimeter tolerance continues to develop, the company intends to support current RA‑4500 MK II customers with a defined upgrade path, providing clear options to maintain compliance and operational confidence as the minimum interference‑tolerance performance criteria for radio altimeters continue to evolve.