Story ID: 551
FreeFlight’s 5G-Tolerant Radar Altimeter Gains TSO Certification
By: Gregory Polek
Caption: The RA-4500 MK II resists 5G interference 
Word Count: 278
FreeFlight Systems’ Terrain Series RA-4500 MK II radar altimeter has received Technical Standard Order (TSO) certification, the company said on the opening day of NBAA-BACE 2023.
Designed as a drop-in replacement for RA-4000 and RA-4500 radar altimeters installed before the emergence of spurious C-band interference caused by 5G network transmissions, the RA-4500 MK II simplifies retrofit installations by supporting existing antennas, control heads, and cabling. For more display options, FreeFlight offers the RAD45 standalone indicator, which meets EASA AMC1 SPA.NNVIS.110(b) guidelines.
Since October 2021, FreeFlight has completed major certification milestones such as successful flight and Alternative Method of Compliance (AMOC) tests while working toward and receiving TSO certifications on the RA-6500, RA-5500, and RA-4500 MK II radar altimeters.
The FAA recently issued two final rulings as airworthiness directives (ADs) by revising the original blanket AMOC-specific AD from 2021. The AD ensures continued operations for aircraft and rotorcraft in the presence of C-band 5G interference. FreeFlight Systems’ Terrain series radar altimeters meet the power spectral density curve threshold (known in the community as the “Group 4” curve) specified in the ADs.
FreeFlight Systems is an active member of the RTCA SC-239 working group developing the next generation of minimum operational specifications 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,” noted company president Anthony Rios. “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.”