FreeFlight Systems' Terrain series RA-4500 MK II radar altimeter has received Technical Standard Order (TSO) certification to meet performance standards required for airborne low-range radar altimeters from the 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, meet the power spectral density (PSD) 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 (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,” says president Anthony Rios.

Designed for all segments of aviation, including commercial transport, business and general aviation, military and defence, 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 per cent reduction in volume from legacy units currently in the field.

The 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.