Proposed rule · 2026-20677

Airworthiness Directives; Various Helicopters

The FAA proposes to adopt a new airworthiness directive (AD) for all helicopters equipped with a radio (also known as radar) altimeter. This proposed AD was prompted by the determination that radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations in the 3.7 to 3.98 GHz frequency band (5G Lower C-Band) while operating in Canadian airspace. This proposed AD would require revising the existing rotorcraft flight manual (RFM) for the helicopter to incorporate limitations prohibiting certain operations requiring radio altimeter data when operating within Canadian airspace. The FAA is proposing this AD to address the unsafe condition on these products.