Skip to page content

USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

United States Department of Transportation United States Department of Transportation

Advisory Circulars (ACs)

Search Results

Number, title, description, or office

Advisory Circulars (ACs) search results
Number Title Status Office Date
91-75 Attitude Indicator

Provides a method to substitute an approved attitude indicator for the rate-of-turn indicator mandated by Title 14 of the Code of Federal Regulations (14 CFR) part 91, section 91.205(d)(3). This AC excludes airplanes covered by section 91.205(d)(3)(i) and (ii).

Active AFS-400 2003-06-25
91-85B Authorization of Aircraft and Operators for Flight in Reduced Vertical Separation Minimum (RVSM) Airspace

This advisory circular (AC) provides airworthiness and operational authorization guidance material for operators, pilots, certificate holders, and/or program managers conducting Title 14 of the Code of Federal Regulations (14 CFR) part 91, §§ 91.180 and 91.706 Reduced Vertical Separation Minimum (RVSM) operations.

Active AFS-400 2019-01-29
120-91A Airport Obstacle Analysis

This AC describes acceptable methods and guidelines for developing takeoff and initial climbout airport obstacle analyses andin-flight procedures to comply with the intent of the regulatory requirements of Title 14 of the Code of Federal Regulations (14 CFR) part 121, §§ 121.177 and 121.189; part 135, §§ 135.367, 135.379, and 135.398; and other associated one-engine-inoperative (OEI) requirements relatingto turbine-engine-powered airplanes operated under parts 121 and 135.

Active AFS-400 2020-01-13
91-70D Oceanic and Remote Continental Airspace Operations

The principal regulatory reference for this guidance is Title 14 of the Code of Federal Regulations (14 CFR) § 91.703, which incorporates International Civil Aviation Organization (ICAO) Annex 2, Rules of the Air, by reference.

Active AFS-400 2025-04-03
90-80C Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas with Change 1

This AC provides operational approval information for operators conducting operations under Title 14 of the Code of Federal Regulations (14 CFR) parts 91, 91 subpart K (part 91K), and 135 to support issuance of operations specifications (OpSpec) or letters of authorization (LOA).

Active AFS-400 2017-12-21
90-114C Automatic Dependent Surveillance-Broadcast Operations

The intent of this AC is to facilitate operations using Automatic Dependent Surveillance-Broadcast (ADS-B) technology in compliance with Title 14 of the Code of Federal Regulations (14 CFR) §§ 91.225 and 91.227. The appendices provide guidance on additional ADS-B Out and ADS-B In operations that may be authorized by the Administrator.

Active AFS-400 2025-01-14
120-76E Authorization for Use of Electronic Flight Bags

It is intended for all operators conducting flight operations under Title 14 of the Code of Federal Regulations (14 CFR) part 91 subpart K (part 91K), 121, 125, or 135 who want to replace required paper information or utilize other select applications as part of EFB functionality.

Active AFS-400 2024-06-12
90-120 Operational Use of Airborne Collision Avoidance Systems

This AC provides an acceptable means, but not the only means, to address operational use of Airborne Collision Avoidance Systems (ACAS) in compliance with Title 14 of the Code of Federal Regulations (14 CFR) part 91, 121, 125, 129, and 135 requirements. Title 14 CFR uses the term Collision Avoidance System (CAS) or Traffic Alert and Collision Avoidance System (TCAS) to describe what Title 49 of the Code of Federal Regulations (49 CFR) and the international community has named ACAS.

Active AFS-400 2024-11-20