Skip to Content

FreeFlight’s 5G-Tolerant RA-4500 MKII Radar Altimeter Gains TSO Certification

Share on facebook
Share on google
Share on twitter
Share on linkedin
Share on pinterest

LAS VEGAS, NV, October 17, 2023 – FreeFlight Systems, a NextGen aviation leader specializing in avionics design, development, and manufacturing, today announced that the TERRAIN Series RA-4500 MK II radar altimeter has received a Technical Standard Order (TSO) certification to meet performance standards required for airborne low-range radar altimeters  from the Federal Aviation Administration (FAA).

The RA-4500 MKII is elegantly designed as a simple drop-in replacement for RA-4000 and RA-4500 radar altimeters installed prior to the emergence of spurious 5G C-band interference caused by 5G network transmissions.

Developed with existing installations in mind, the RA-4500 MKII simplifies retrofit installations by supporting existing antennas, control heads, and cabling as needed. For additional display options, FreeFlight Systems offers the RAD45 standalone indicator which meets EASA AMC1 SPA.NVIS.110(b) guidelines.

Since October 2021, FreeFlight Systems has completed major certification milestones, including successful flight and Alternative Method of Compliance (AMOC) testings, while working towards and receiving TSO certifications on the RA-6500, RA-5500, and RA-4500 MK II radar altimeter.

The FAA recently issued two final rulings as Airworthiness Directives (AD’s) by revising the original blanket AMOC specific AD from 2021. The AD ensures continued operations for aircraft and rotorcraft alike in the presence of C-band 5G interference. FreeFlight systems Terrain series radar altimeters including the recently certified RA-4500 MKII radar altimeter meets the power spectral density (PSD) curve threshold (known in the community as the “Group 4” curve) specified in the AD’s. FreeFlight Systems is an active member of the RTCA SC-239 working group developing the next generation of minimum operational specifications (MOPS) for 5G interference tolerant radar altimeters.

“FreeFlight Systems is a global leader in radar altimetry with hundreds of radar altimeters installed on in-use aircraft. In foreshadowing the impact that this may have on our dealer, operator, and OEM partners, we designed a simple but effective, solution that will satisfy industry requirements while alleviating the burden of having to install a completely new system twice,” said Anthony Rios, President, FreeFlight Systems.

Designed for all segments of aviation, including commercial transport, business and general aviation, military and defense, rotorcraft, urban air mobility and uncrewed aviation, the TERRAIN Series radar altimeters are the lightest, most advanced in their class with up to a 60% reduction in volume from legacy units currently in the field.

The state-of-the-art radar altimeters will equip operators with a 5G-tolerant solution, ensuring accurate altitude measurement readings critical for safe approach and landing operations in urban and mountainous terrain. The TERRAIN Series demonstrated that 5G interference rejection enables users to operate aircraft safely, even in close proximity to 5G cellular towers.

To learn more about the TERRAIN Series or how spurious 5G C-bands may affect your organization, please contact, or visit

About FreeFlight Systems

As NextGen aviation leader, FreeFlight Systems designs and manufactures high-performance avionics for flight safety. These solutions deliver substantial safety and unmatched reliability that is critical for modern flight operations. Founded in 2001 and based in Texas, the company pioneered the first certified aviation WAAS/GPS receiver and their first rule-compliant UAT ADS-B system. FreeFlight Systems is now a global aerospace leader, specializing in SBAS/GNSS sensors, radar altimeters, flight management systems and other NextGen aerospace avionics. For more information, visit

Press Contacts

Latest Announcements