By David Shepardson

WASHINGTON (Reuters] – According to sources, and a letter seen at Reuters, FAA has voiced serious concern about a plan that would use spectrum to support 5G wireless networks for aviation safety.

C-Band is expected to be in use for more than one year. This alarms the aviation industry. The spectrum will be available to network carriers in 46 markets starting December 5.

In an unreported letter dated Oct. 6, Bradley Mims, FAA deputy administrator, stated that the agency shared “deep concern” about interference to radar altimeter performance due to 5G network operation in the C-band.

A spokeswoman for the FAA stated Friday that it continues to work with other agencies in order to ensure safe coexistence of aviation and 5G technology.

The Federal Communications Commission said Friday it remains committed to ensuring air safety as the agency’s successful track record demonstrates, while moving forward with the deployment of new technologies that support American business and consumer needs.”

October 14 was a long meeting between the FAA and the aviation industry to address the issue. According to sources, both FCC and FAA officials had held many discussions on the subject.

Two FAA officials confirmed to Reuters that the FAA will soon publish a Special Airworthiness Information Bulletin (SAILB) and an Airworthiness Directive about this issue. This confirms a Wall Street Journal report.

The aerospace and airline sector met with the FCC in August https://ecfsapi.fcc.gov/file/1081157361951/Aviation%20and%20Aerospace%20Ex%20parte%20Notice%20Aug%206%202021%20w%20OET%20WTB%20IB.pdf, warning without changes “major disruptions to use of the National Airspace System can be expected from the rollout of 5G” and added the FAA will be forced to “drastically reduce aviation operational capacity.”

Wireless trade group CTIA said Friday 5G networks can safely use C-band spectrum “without causing harmful interference to aviation equipment,” and cited numerous active 5G networks using this spectrum band in 40 countries… Any delay in activating this spectrum risks America’s competitiveness.”

Retrofitting altimeters using “out-of band filters” is a longer-term option. However, it could take many years. “Many thousands of civil airplanes are likely to be affected,” the aviation industry stated.