AD 2023-11-07: Various Helicopters

What the FAA requires

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.

Read the full directive on the Federal Register →

Applicability

Comment summary: Sikorsky requested that the FAA revise the proposed AD to exempt helicopters conducting ambulatory, health, emergency, and search and rescue (SAR) operations. Sikorsky stated that the inability to conduct these lifesaving operations due to the AD would have a negative humanitarian and social impact. FAA response: The FAA disagrees. The FAA has determined that regardless of the purpose of a flight, erroneous radio altimeter behavior creates an unacceptable risk during the operations prohibited by the AD. To remove those prohibitions from the RFM, operators may modify their helicopters to a radio altimeter tolerant helicopter as defined in paragraph (g)(1) of this AD. Request

Part numbers this directive names

This directive does not name specific part numbers in its text; it applies by aircraft model. See the applicability above and the manufacturer's service bulletin it references.