Airworthiness Directives; Various Helicopters

The FAA is superseding Airworthiness Directive (AD) 2021-23- 13, which applied to all helicopters equipped with a radio (also known as radar) altimeter. AD 2021-23-13 required revising the limitations section of the existing rotorcraft flight manual (RFM) for your helicopter to incorporate limitations prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-Band interference in areas as identified by Notices to Air Missions (NOTAMs). Since the FAA issued AD 2021-23-13, the FAA determined that additional limitations are needed due to the continued deployment of new 5G C-Band base stations whose signals are expected to cover most of the contiguous United States at transmission frequencies between 3.7- 3.98 GHz (5G C-Band). This AD requires revising the limitations section of the existing RFM to incorporate limitations prohibiting certain operations requiring radio altimeter data, due to the presence of 5G C- Band interference. The FAA is issuing this AD to address the unsafe condition on these products. In addition, the FAA is requesting comment on the change to the spurious emission level requirement.