Airline delays mark 5G C-band deployment

The FAA moved quickly to expand the list of aircraft-altimeter combinations approved for unrestricted operation in areas where the new 5G C-band transmitters prompted hundreds of notices to air missions that restricted the use of certain procedures at dozens of airports around the country.

A voluntary delay in powering up selected airport-adjacent transmitters announced by AT&T and Verizon, while welcomed by advocates including AOPA and the National Business Aviation Association, did not bring significant relief for operators of smaller aircraft, including business jets, turboprops, and helicopters that use radar altimeters for critical guidance during low-visibility operations. The FAA announced January 20 that additional approvals had been issued for transport aircraft made by Boeing and Airbus and equipped with certain radar altimeters, allowing them to disregard the restrictions imposed by the roughly 1,500 notams issued ahead of C-band activation. While those approvals enable about 78 percent of the commercial fleet, including some regional jets, to perform low-visibility landings regardless of local 5G activity, they do not apply to aircraft (even those using the same radar altimeter) used for business aviation operations.

While the FAA granted an exemption sought by Helicopter Association International that allows helicopter air ambulance operations to proceed in areas where 5G C-band signals are now present (including areas far from airports), that exemption requires certain mitigations (such as the use of ground personnel or night vision goggles) and does not apply to some of the same helicopters flown for missions such as executive transportation.

AOPA continues to work with a coalition of aviation stakeholders formed to promote a commonsense approach to 5G C-band implementation, a coalition that began advocating long before the Federal Communications Commission approved the use of wireless base stations operated in a frequency range that has been shown to interfere with radar altimeters, sensitive instruments used to accurately measure height from obstacles, or the ground. The C-band frequencies were auctioned to wireless carriers in December 2020, notably after the aviation coalition documented evidence that the devices could interfere with radar altimeters.

Now that the 5G C-band transmitters are (mostly) active, it will likely take time to approve business aircraft, and small GA aircraft if equipped, for unrestricted operation in a 5G environment. Some of the less powerful (and less expensive) models of radar altimeter used on smaller aircraft may never be cleared for unrestricted use in a 5G C-band environment. It remains to be seen how that will be resolved.

"The FCC could have performed this rollout in a safer manner with much less negative impact on aviation operations had they listened to the concerns raised by industry and the FAA from the beginning. We want to make sure that any future changes that impact the aviation system are performed in an effective manner and not just rolled out without fully considering and addressing identified risk and ensuring a safe system," said AOPA Vice President of Regulatory Affairs Murray Huling. "We appreciate the FAA's methodical approach in addressing this issue and its prioritization of safety."