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FreeFlight Systems unveils radar altimeters that mitigate 5G interference

January 26, 2021  By Helicopters Staff

­FreeFlight Systems announced the release of a new series of radar altimeters for heavy rotorcraft, turboprops, business aviation, and military segments designed to mitigate 5G interference.

Decades ago, when the original specification was created for the radar altimetry, the Radio Frequency (RF) environment was protected. However, with new terrestrial broadband datalink systems such as 5G, and as identified by the RTCA Special Committee, these devices may be compromised in the new environment.

The new radar altimeters feature redesigned RF circuitry built to withstand 5G interference. This adaptation will increase this critical sensor’s availability and reliability – the only sensor onboard an aircraft capable of detecting clearance height above terrain – in those challenging RF interference environments.

The new set of radar altimeters, dubbed the Terrain Series, includes the RA 5500, RA 6500, and RA 7500 radar altimeters for multiple aviation markets, beginning with the RA 6500, which is focused on Part 29 Heavy Rotorcraft and business jet markets. The RA 6500 also features comprehensive interface capabilities, including the ARINC 552 legacy interface, which allows integration with legacy analog indicators, greatly simplifying the retrofit of the system. As an additional display option, the RA 6500 can be paired with the FreeFlight Systems RAD45 standalone indicator, which meets EASA AMC1 SPA.NVIS.110(b) guidelines.


The TSO’d, DAL-B rated RA 6500 meets the FAA’s most rigorous design standards, including TSO-C87a Class A, ETSO-2C87, DO-160G, and DO-178C, ensuring commercial transport and military-grade operability.

The RA 6500’s small footprint means that it can easily be installed in place of legacy altimeters from multiple manufacturers. The existing antennas can also be used in most installations, making the RA 6500 a very straightforward retrofit solution.

“The design represents the forward-thinking, future proof technology that FreeFlight Systems is known for,” said Tim Taylor, FreeFlight Systems CEO and president in a statement. “The Terrain family is designed for robust operation in future environments and platforms while offering a simple retrofit path for replacement of older less capable altimeters in service today.”

The Terrain Series altimeters feature dual-install capability making them suitable for installation in Part 29 rotorcraft and larger fixed-wing aircraft. The feature-rich radar altimeters have an update rate of 25 times per second (25 Hz), Frequency-Modulated Continuous-Wave (FMCW) at 4.3 GHz center frequency, an altitude range of -20 to 2,500 ft., antenna response angles of up to ±20° pitch and ±30° roll, and a service ceiling of 55,000 ft. This design allows for extraordinary robust operations and reliability, true to FreeFlight Systems’ long history of high integrity and dependable avionics.



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