June 24, 2022

Telecommunications providers AT&T and Verizon recently agreed to a new delay in powering up 5G transmission towers near certain airports, but the FAA warned that aviation stakeholders must not be complacent in moving toward permanent solutions to mitigate the possible effects of these networks on important aircraft systems.

Both companies agreed earlier this year to operate those towers under reduced power until July 5 to help reduce potential interference from 5G signals in the “C-band” adjacent to frequencies used by radar altimeters, a critical piece of safety equipment in commercial airliners and many business aircraft.

On June 21, the two companies agreed to push that increased power date forward one year to July 2023. While the delay buys some much-needed time for the industry, earlier this month FAA Acting Administrator Billy Nolen emphasized the need for avionics manufacturers and operators to find permanent solutions to eliminate 5G interference.

In his letter to commercial airline groups, Nolen noted that Verizon and AT&T are but two of 21 telecommunications providers with plans to roll out 5G networks in the coming months. “[T ]he dynamic nature of this situation underscores the need for the aviation industry to move with all due haste to protect the fleet against known vulnerabilities to 5G C-band interference,” Nolen reiterated.

Review the full letter (PDF)

Heidi Williams, NBAA senior director for air traffic services and infrastructure, noted many business aviation OEMs have implemented alternative means of compliance (AMOC) to assist flight crews operating in regions with potential 5G interference, as the industry works to implement permanent solutions.

“The FAA has met several times this month with avionics OEMs and other industry stakeholders to nail down a timeline for ensuring a solution is in place for radar altimeter filters,” she added. “However, it’s not yet clear what mitigations will be required for every type of radar altimeter now in use.”

“Fortunately, the AMOCs in place allow most business aviation operations to continue as these fixes are identified,” Williams continued. “NBAA recommends operators continue to monitor 5G NOTAMs and remain in contact with their aircraft and avionics OEMs to ensure they are utilizing the most up-to-date equipment and procedures.”

In addition to providing real-time measurement of an aircraft’s clearance over terrain and other obstacles, radar altimeters may be integrated with other systems, including terrain avoidance and warning systems and autoland capabilities, as well as ground spoilers, anti-skid braking, pressurization and other seemingly unrelated aircraft systems.