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The FAA updated its guidance on the potential adverse effects of radio altimeters from 5G C-Band interference and is recommending operators equip aircraft with 5G C-Band tolerant radio altimeters soon.
The latest guidance is the first update since the July 1 deadline asking airlines to equip aircraft with filters to mitigate risk and reduce the impact of 5G C-Band interference. The guidance, published in SAFO 21007 - Risk of Potential Adverse Effects on Radio Altimeters when Operating in the Presence of 5G C-Band Interference was revised on Oct. 12. The FAA explains that the risk of interference is the highest for aircraft that have not been retrofit. The interference can cause systems to operate unexpectedly while in flight and during critical phases such as takeoff, approach and landing. The SAFO lists systems that could be affected by the interference, but the impact could extend beyond the list. The systems that could be impacted include the autothrottle, thrust reversers, tail strike prevention systems, Terrain Awareness Warning systems, Traffic Alert and Collision Avoidance systems and the engine and wing anti-ice systems.
Now, 19 more wireless companies are beginning to deploy 5G C-Band emitters throughout the country. With the burgeoning rollout imminent, the FAA said the process of NOTAM and Alternative Method of Compliance runway lists are untenable. With the latest update, the FAA encourages all operators to equip aircraft with tolerant radio altimeters "as soon as possible."
"With the deployment of 5G C-Band throughout the contiguous U.S., it's imperative all operators and pilots assume that 5G C-Band emitters are deployed anywhere they fly in the contiguous U.S. and any aircraft not equipped with a 5G C-Band tolerant RA will be subject to harmful interference," the SAFO said.
The NBAA weighed in, supporting the FAA's latest update.
"NBAA encourages aircraft owners and operators to consult with their OEMs regarding the need and availability of upgrades or filters," said Heidi Williams, NBAA senior director of air traffic services and infrastructure. "Pilots and operators should continue to watch for relevant NOTAMs related to 5G interference risks."