EASA AD CF-2025-54
Navigation — 5G C-Band wireless Broadband Interference with Radio Altimeter System when operating in Canadian airspace affected by 5G C-Band wireless signals
Summary
Airworthiness Directive CF-2025-54 addresses interference issues between 5G C-Band wireless broadband signals and radio altimeter systems on De Havilland Aircraft of Canada DHC-8-100/-200/-300 aeroplanes operating in Canadian airspace. The directive mandates configuration of these aircraft as Radio Altimeter Tolerant (RAT) to ensure safe operation amid 5G C-Band deployments. It applies to all serial numbers of the specified aircraft models and focuses on mitigating erroneous radio altimeter data caused by 5G interference.
What Changed
This new Airworthiness Directive introduces operational limitations and modification requirements for non-radio altimeter tolerant DHC-8 aeroplanes to mitigate 5G C-Band interference risks. It requires placarding, crew briefing, and installation of specific labels within 53 days of the effective date, followed by mandatory radio altimeter system modifications using approved service bulletins. The directive serves as an interim safety measure pending further regulatory actions.
Why It Matters
This directive is critical for aviation professionals to maintain flight safety in Canadian airspace where 5G C-Band signals may disrupt radio altimeter accuracy. Operators and maintenance teams must ensure compliance to avoid unreliable altitude data that could affect aircraft systems and flight operations. The directive also clarifies compliance pathways and timelines, aiding regulatory adherence and risk mitigation.
What To Do
Operators of De Havilland DHC-8-100/-200/-300 aeroplanes must, within 53 days of November 19, 2025, install cockpit labels, brief flight crews on operational limitations, and comply with AFM procedures to mitigate interference risks. Subsequently, they must modify the radio altimeter systems per specified Honeywell RT-300 service bulletins to achieve Radio Altimeter Tolerant status, which terminates earlier operational restrictions. Contact Transport Canada for alternative compliance methods if necessary.