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FreeFlight Systems’ 5G-Tolerant Radar Altimeters Prove Exceptional Performance During AMOC Testing

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FreeFlight Systems' TERRAIN Series radar altimeters

DALLAS, TX, MARCH 8, 2022 – FreeFlight Systems, a NextGen aviation leader specializing in avionics design, development, and manufacturing, today announced that their TERRAIN Series radar altimeters (RADALTs), designed to mitigate 5G interference, have completed the first round of formal testing with exceptional results.

In 2019, preempting potential interference from C Band 5G telecommunications networks, FreeFlight Systems launched the development of an innovative, clean sheet radar altimeter design that would deliver orders of magnitude greater signal rejection from out-of-band interference sources.

The resulting new TERRAIN Series radar altimeters are now undergoing the testing required to support Alternative Method of Compliance (AMOC) with exceptional results – further proving that its robust design can coexist with C Band 5G networks.

The testing, which employed industry-standard test setup, methodology, and analysis, was used to determine interference tolerance of the RADALTs in terms of their protection radius, or how close to 5G towers the RADALT can get without being affected. The better the interference tolerance of the RADALT, the smaller the protection radius around a given 5G antenna can be.

Based on the test results, the TERRAIN Series demonstrated a protection radius of at least an order of magnitude better than 1.o nautical miles (NM). This means that the new line of RADALTs, with its unique, patent-pending combination of a redesigned internal RF filtering circuitry and innovative Digital Signal Processing (DSP), provides industry-leading 5G interference mitigation compared to other in-service RADALTs.

“We set out to design the TERRAIN Series to co-exist with C Band 5G networks from a clean sheet. Today, it is the only altimeter in the market that has been specifically designed for this,” says Anthony Rios, President at FreeFlight Systems. “We started working towards this design nearly two years ago and are proud to see the exceptional performance results. We now look forward to seeing the benefits to safety our radar altimeters will have for operators around the world.”

FreeFlight Systems will continue the testing of the TERRAIN Series radar altimeters and improve performance as more refined AMOC methodologies emerge.

“Despite the exceptional performance, we do not want to stop here,” continues Rios. “The innovative design enables FreeFlight Systems to continue to refine the 5G interference performance of the TERRAIN Series through software enhancements. Further improvements will be available to TERRAIN Series customers as field loadable software updates – effectively future-proofing the radar altimeter for FAA minimum performance standards expected to evolve in the future.”

The TERRAIN Series’ Design Assurance Level (DAL) B criticality, dual-install compatibility, altitude measurement range of up to 2,500 feet, and 55,000 ft service ceiling make them ideal for new or retrofit Part 29 rotorcraft and larger fixed-wing aircraft installations. The small footprint design means that it can easily be installed in place of legacy altimeters from various manufacturers.

For simplified retrofit installations, the TERRAIN Series altimeters support existing antennas, cockpit displays, and wiring provisions already installed on the aircraft. Further, to support a wide range of aircraft platforms across heavy rotorcraft, regional air transport, turboprops, business aviation, and military segments, the TERRAIN Series incorporates the latest ethernet connectivity standards for new platforms while retaining an analog ARINC 552 interface for integration with legacy indicators and components. For additional display options, FreeFlight Systems offers the RAD45 standalone indicator which meets EASA AMC1 SPA.NVIS.110(b) guidelines.

FreeFlight Systems is now fielding orders for the new TERRAIN Series radar altimeters. To service customers most effectively, FreeFlight Systems has reserved limited quantities for customers who place orders during the HAI HELI-EXPO from March 8th to March 10th. To order, please see us at Booth 8239 or 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/GSP 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

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