FAA warns pilots that 5G C-Brand spectrum could cause ‘flight diversions’ in certain locations

Zac Hall | Dec 7 2021 - 8:59 am PT

There’s an awkward debate over 5G happening between U.S. phone carriers and the Federal Aviation Administration. The latest development comes in the form of two new airworthiness directives regarding 5G being adopted by the FAA.

AT&T and Verizon acquired C-Band spectrum licenses to expand 5G spectrum before the FAA requested a delay over safety concerns for pilots. Despite approval from the Federal Communications Commission that includes unused spectrum to protect altimeters, the FAA is being lobbied to halt the rollout of expanded 5G spectrum for fear of interference with airplanes.

Both carriers originally planned to launch additional 5G spectrum in early December, but a one-month delay was agreed upon to satisfy the FAA. The FCC found no evidence of C-Band spectrum 5G interfering with aircraft equipment during its study prior to approval.

More recently, 5G service providers have offered a compromise to the FAA that would see lower 5G cell-tower power levels, especially near airports, while the FAA studies 5G’s effect on airplane sensors.

Now the FAA has released formal safety directives for pilots of airplanes and helicopters regarding the risk of interference from 5G with air safety equipment. Specifically, the FAA is informing pilots to limit reliance on radio altimeters in certain conditions, such as low visibility when flying in areas with 5G C-Band signals. The FAA provides notices to pilots before flight in affected areas.

The FAA is issuing this AD because the agency has determined the unsafe condition as described previously is likely to exist or develop in transport and commuter category airplanes with a radio altimeter as part of their type design. […] These limitiations could prevent dispatch of flights to certain locations with low visibility, and could also result in flight diversions.

What does this mean for carrier efforts to improve 5G service across the country? The development is not completely determinant, but it isn’t the signal from the FAA that carries want right now.

The FAA notes that these safety efforts go into effect immediately without request for comment before implementation. “The urgency is based on C-Band wireless broadband deployment, which is expected to occur in phases with operations beginning as soon as January 5, 2022,” the FAA writes.

The FAA is working closely with the Federal Communications Commission and wireless companies, and has made progress toward safely implementing the 5G expansion. We are confident with ongoing collaboration we will reach this shared goal.

Stay tuned as this story unfolds into next year.