On September 29, 2026, the Federal Aviation Administration (FAA) published a final rule establishing minimum performance requirements for radio altimeter systems. This regulation aims to ensure that these systems are tolerant to interference from adjacent wireless services operating in the Upper C-band spectrum.

The rule applies specifically to aircraft operating under parts 91, 121, and 129, covering a wide range of civil aviation categories. It sets clear compliance timelines for affected operators to meet the new standards.

This regulatory measure reflects the FAA's commitment to maintaining the safety and reliability of critical aircraft systems amid the evolving wireless communication environment. Aircraft operators are advised to review the rule and plan accordingly to ensure compliance within the defined timeframes.