# Airworthiness Directives; Transport and Commuter Category Airplanes
> **Rule** · Final rule. · Published 2023-05-26 · Effective 2023-05-26 · 88 FR 34065
## Document
- **Document number:** 2023-11371
- **Category:** airworthiness
- **Manufacturer:** Transport and Commuter Category
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 88 FR 34065
- **Publication date:** 2023-05-26
- **Effective date:** 2023-05-26
- **FAA docket:** Docket No. FAA-2022-1647
## Abstract

The FAA is superseding Airworthiness Directive (AD) 2021-23- 12, which applied to all transport and commuter category airplanes equipped with a radio (also known as radar) altimeter. AD 2021-23-12 required revising the limitations section of the existing airplane/ aircraft flight manual (AFM) to incorporate limitations prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-Band interference as identified by Notices to Air Missions (NOTAMs). Since the FAA issued AD 2021-23-12, the FAA determined that additional limitations are needed due to the continued deployment of new 5G C-Band stations whose signals are expected to cover most of the contiguous United States at transmission frequencies between 3.7-3.98 GHz. For certain airplanes, this AD requires revising the limitations section of the existing AFM to incorporate limitations prohibiting certain operations requiring radio altimeter data, due to the presence of 5G C-Band interference. This AD also requires modifying certain airplanes to allow safe operations in the U.S. 5G C-Band radio frequency environment. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2023/05/26/2023-11371/airworthiness-directives-transport-and-commuter-category-airplanes)
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