May 17, 2023

Heidi Williams, NBAA’s senior director of air traffic services and infrastructure, recently shared business aviation’s concerns on 5G implementation during Aviation International News’ webinar: “5G & Business Jets – What Does This Mean for Your Flying?”

Williams was joined by Collins Aerospace Associate Director of Programs Alex Haak.

Haak explained a buffer spectrum range around radio altimeters (RadAlt) frequencies is now infringed upon by the terrestrial carriers’ use of 5G.

Terrain awareness and warning systems and enhanced ground proximity warning systems have the greatest potential to be affected by interference or an undetected RadAlt error. These systems may not provide ground proximity warnings, altitude callouts or windshear warnings correctly. Single RadAlt installations could enhance that risk. Further, crewmembers can become desensitized to error warnings due to the frequency of false alerts.

“We recommend people upgrade their systems as soon as those upgrades become available,” Haak said.

A draft Airworthiness Directive on RadAlt standards, which describes the need to add a filter or upgrade the RadAlt prior to July 1, 2023, was published in early 2023.

July 1 marks the end of a mitigation phase, which includes reduced 5G power settings and varying antenna angles at various airports and other areas. Those temporary efforts limited the chance of interference.

In other words, operators will be at greater risk of 5G interference with RadAlt beginning July 1.

“The FAA has used a phased approach to mitigate the risk of 5G interference with initial efforts around commercial aviation, but there is recognition that there is still a lot of work to do on the business aviation side,” said Williams.

Any business aircraft operator approved for and utilizing certain instrument procedures, including Special Authorization CAT I, Category II and above approaches; head-up display landings; and enhanced vision systems through touchdown, for example, will needs to add a filter or upgrade their RadAlt by July 1.

Almost 200 airports are currently flagged with 5G interference concerns, though this number continues to grow. Pilots should be alert for 5G interference no matter where they’re flying if they’re operating without an upgraded RadAlt.

The good news is that 5G cabin connectivity operates on a different spectrum than terrestrial-based 5G and does not impact cockpit connectivity.

Interference concerns are not as significant in some other regions, particularly European countries, which have built bigger buffer zones, operate 5G at lower power and utilize different antenna angles. Concerns remain in the Asia-Pacific region and could increase over the coming years.

Pilots have reported hundreds of RadAlt anomalies and more than 100 of them have been determined to be the result of 5G interference. RadAlt anomalies should be reported to the FAA directly.

NBAA has worked on this issue for a number of years – even before this frequency spectrum was sold to the telecommunications industry – participating in a related industry coalition, FAA 5G Roundtable, giving testimony before Congress and more.

“We as an industry are not opposed to the rollout of 5G. What we have been concerned about is the impact on the equipment in aviation operations,” said Williams. “This is an issue we have all come together on as an aviation community. It has been a great example of coming together as an industry for a more powerful voice.”