Avionics News October 2022 - 24

5G RADAR ALTIMETERS
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first round of formal testing required to support the
Federal Aviation Administration's required 5G alternative
method of compliance radius, with exceptional results,
proving that its robust design can coexist with C Band 5G
networks. The company will continue the testing of the
Terrain Series radar altimeters and improve performance
as more refined AMOC methodologies emerge.
Importantly, the Terrain Series altimeters are designed
to allow customers to upload software updates that will
ensure it always meets FAA minimum performance
standards as they evolve in the future. On Aug. 16,
FreeFlight Systems announced that the RA-6500 and
RA-5500 Terrain Series radar altimeters had received
technical standard order certification from the FAA.
5G network rollout: an overview
Ensuring the safe rollout of 5G networks was a topic
addressed at the June annual General Meeting of the
International Air Transport Association in Doha, Qatar,
where IATA's Director General Willie Walsh urged
governments to work closely with the aviation industry to
ensure that aviation and incumbent aviation safety systems
can safely coexist with new 5G services.
In the United States, the FAA has been working to
ensure that radio signals from newly activated wireless
telecommunications systems can coexist safely with flight
operations, but the 5G rollout has been rockier in the U.S.
than abroad.
In the U.S., 5G services launched in 46 markets on Jan. 19
using frequencies in the C-band radio spectrum, which can
be close to those used by radio altimeters. That month, after
negotiations involving the FAA and key stakeholders in the
aviation and wireless industries, wireless companies Verizon
and AT&T agreed to a level of voluntary mitigations for a
period of time, which was later extended until July 2023.
" We believe we have identified a path that will continue
to enable aviation and 5G C-band wireless to safely
coexist, " said Acting FAA Administrator Billy Nolen
on June 17. " We appreciate the willingness of Verizon
and AT&T to continue this important and productive
collaboration with the aviation industry. "
To avoid hazardous interference, the FAA requires
that radio altimeters be accurate and reliable. The phased
24 avionics news * october 2022
approach requires operators of regional aircraft with radio
altimeters most susceptible to interference to retrofit them
with radio frequency filters by the end of 2022. This work
has already begun and will continue on an expedited basis.
At the same time, the FAA has worked with wireless
companies to identify airports around which their service
can be enhanced with the least risk of disrupting flight
schedules. Airlines and other operators of aircraft equipped
with the affected radio altimeters must install filters or other
enhancements as soon as possible.
According to the FAA, filters and replacement units for the
mainline commercial fleet should be available on a schedule
that would permit the work to be largely completed by July
2023. After that time, the wireless companies expect to operate
their networks in urban areas with minimal restrictions.
Delivering an adaptable digital platform
IATA's Walsh characterized the FAA's target July 2023
date as " deeply disappointing and unrealistic. The FAA has
not even approved or certified all the safety solutions that
it will require, nor have systems providers been able to say
with certainty when the equipment will be available for
much of the fleet. So how can there be any confidence in the
timeline? " he said.
" Furthermore, FAA can provide no guarantee that airlines
will not have to carry out further upgrades to radio altimeters
as even more powerful 5G networks are deployed in the
near future, " Walsh said. IATA also noted that 19 additional
telecommunications companies are scheduled to deploy 5G
networks by December 2023.
In the context of this short and uncertain timeline, Rios
noted that it will take first-tier OEMs just starting the
development process now at least a couple of years to design
and release a prototype of a 5G-tolerant radar altimeter that
isn't a stopgap solution. " The real solution is a redesign of the
radar altimeter to be better neighbors on the spectrum, so if
you're starting now, it's going to take a long time. "
By comparison, FreeFlight Systems has " designed a
digital platform, and it's available now, " Rios said, noting
that the Terrain altimeter is the only one in the market
that has been specifically designed to coexist with C
Band 5G networks from a " clean sheet. "
" We've made a product that is small, lightweight
and adapts well to small platforms, " he explained. " It's
designed with a digital processor that can be adapted
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Avionics News October 2022

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