Federal Register #FAA-2026-7205

FAA Airworthiness Directive for Boeing 747 Series: Radio Altimeter Interference Mitigation in Canadian Airspace

The Federal Aviation Administration (FAA), under the Transportation Department, has issued an airworthiness directive for all Boeing 747 series airplanes due to potential radio altimeter interference from 5G wireless broadband in Canadian airspace. - Government Buyer: - Federal Aviation Administration (FAA) - Continued Operational Safety Branch, AIR520 - OEM Highlight: - The Boeing Company is the primary Original Equipment Manufacturer (OEM) referenced - Products/Services Requested: - Revision of the Airplane Flight Manual (AFM) for 114 non-radio altimeter tolerant Boeing 747 series airplanes - No specific part numbers provided - Service involves updating manuals to prohibit certain operations (dispatch, takeoff, approach, landing, go-around) relying on radio altimeter data in Canadian airspace - Unique Requirements: - Directive targets unsafe conditions caused by 5G Lower C-Band (3.7-3.98 GHz) interference - Optional modifications to aircraft (radio altimeter replacement or filter addition) can terminate operational limitations - Compliance required before further flight in Canadian airspace - Applies to all Boeing 747 variants: -100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F - No specific product part numbers or quantities for modifications are listed - The directive is an interim action and may be updated if Canadian 5G regulations change

Description

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 747 series airplanes including -100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, and -400F. This AD addresses interference issues with radio altimeters caused by wireless broadband operations in the 3.7-3.98 GHz frequency band (5G Lower C-Band) while operating in Canadian airspace. The interference may cause certain airplane systems to malfunction during critical phases of flight such as takeoff, approach, landing, and go-arounds, increasing flightcrew workload and potentially reducing the ability to maintain safe flight and landing. The AD requires revising the airplane flight manual to incorporate limitations prohibiting certain operations requiring radio altimeter data when operating in Canadian airspace to mitigate this unsafe condition.

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