Navigation — 5G C-Band wireless Broadband Interference with Radio Altimeter System when operating in the contiguous United States of America (U.S.) airspace.
- Published
- Effective
AI-generated summary of the official EASA document. Verify against the PDF before acting.
What to do
Operators of De Havilland DHC-8-100, -200, and -300 aircraft must install the specified cockpit placard within 60 days of November 6, 2025, and inform flight crews about the 5G interference risks and AFM limitations. Within four months of the effective date, affected aircraft must undergo radio altimeter modifications as per De Havilland service bulletins to upgrade to tolerant radio altimeters. Compliance with these measures is mandatory before operating in the contiguous U.S. airspace.
Summary
The Canadian Airworthiness Directive CF-2025-52 addresses interference caused by 5G C-Band wireless broadband signals with radio altimeter systems on De Havilland Aircraft of Canada Limited DHC-8-100, -200, and -300 series aircraft operating in the contiguous United States airspace. This directive mandates modifications to affected aircraft radio altimeters to ensure tolerance against 5G interference and introduces interim operational limitations. It specifically targets aircraft equipped with Honeywell RT-300 radio altimeters.
What changed
CF-2025-52 introduces requirements for installing tolerance modifications on radio altimeters of affected DHC-8 aircraft to mitigate 5G C-Band interference. It also mandates the placement of cockpit placards and reinforces operational limitations in the Aircraft Flight Manual (AFM) for aircraft with non-tolerant radio altimeters. The directive sets compliance deadlines for placard installation within 60 days and radio altimeter modification within four months of the effective date.
Why it matters
This directive is critical for aviation professionals as 5G C-Band interference can cause erroneous radio altimeter readings, leading to incorrect height determination, delayed mode transitions, and potential flight safety risks. Operators and maintenance teams must ensure compliance to maintain safe flight operations and avoid increased pilot workload or inadvertent system inhibitions. The directive aligns Canadian regulations with FAA mandates, ensuring harmonized safety standards for aircraft operating near U.S. airspace.
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