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United States Department of Transportation United States Department of Transportation

Advisory Circulars (ACs)

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Advisory Circulars (ACs) search results
Number Title Status Office Date
20-158B The Certification of Aircraft Electrical and Electronic Systems for Operation in the High-Intensity Radiated Fields (HIRF) Environment

This AC provides guidance for a new type certificate (TC) or a change to an existing TC when the certification basis requires you to address the HIRF certification requirements of §§ 23.1308 (Amendment 23-57), 23.2520 (Amendment 23-65), 25.1317, 27.1317, or § 29.1317.

 Active AIR-626 2024-05-20
20-141B Airworthiness and Operational Approval of Digital Flight Data Recorder Systems with Change 1

This advisory circular (AC) contains changes to Appendix 3. This AC provides information on certification (design and installation) and continued airworthiness of digital flight data recorder systems (DFDRS).

Active AIR-626 2010-08-17
20-167B Airworthiness Approval of Enhanced Vision System, Enhanced Flight Vision System, and Combined Vision System Equipment

This advisory circular (AC) provides guidance for gaining airworthiness approval for enhanced vision systems in aircraft.

Active AIR-626 2025-09-08