Aircraft Certification Service (AIR) Draft Advisory Circulars (ACs) Open for Comment
| Document Title: | AC 33.87-1A Chg 1, Engine Overtorque Test, Calibration Test, Endurance Test, and Teardown Inspection for Turbine Engine Certification (§§ 33.84, 33.85, 33.87, and 33.93) |
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| Summary: | This advisory circular (AC) change updates the references provided in the original document and aligns the content with current terminology and regulatory language. The AC provides guidance for showing compliance to Title 14, Code of Federal Regulations (14 CFR) 33.87 when an applicant proposes to perform tests out of the normal sequence described in §§ 33.87 (b), (c), (d), (e), (f), or (g), as applicable. |
| Documents for Download: | Draft Document Comment Matrix |
| Comments Due: | January 30, 2026 |
| How to Comment: | Email Comments to: 9-AVS-TechWriters@faa.gov |
| Document Title: | AC 20-199, Installation of an Airborne Low-Range Radio Altimeter System |
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| Summary: | This advisory circular (AC) provides guidance for the installation of a radio altimeter (RA) system to comply with the requirements of title 14, Code of Federal Regulations (CFR) § 91.220(b), for operation in the airspace of the 48 contiguous United States (U.S.) and the District of Columbia. An RA system consists of an RA transceiver, RA antenna(s), and display or indicator. This AC provides guidance for all of the components of the RA system as well as for the use of existing RA antenna(s) and display or indicator as part of the RA system installation. This AC includes guidance for the system installation and testing to assure proper functioning of the installed RA system, including the radio frequency interference tolerance, as well as proper functioning of integrated avionics and flight control systems that utilize the RA. |
| Documents for Download: | Draft Document Comment Matrix |
| Comments Due: | February 9, 2026 |
| How to Comment: | Email Comments to: 9-AVS-TechWriters@faa.gov Mail Comments to: Michael H. Harrison Federal Aviation Administration Northwest Mountain Regional Office 2200 S. 216th St. Des Moines, WA 98198 |
Related Information
- Final Aircraft Certification advisory circulars, other policy documents, and technical standard orders (TSOs) are available on FAA's Dynamic Regulatory System (DRS)
- Advisory Circulars (ACs)
- FAA Regulations
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- Policy & Guidance
- To comment on rulemaking documents, please visit the DOT Docket Management System.
Last updated: Wednesday, January 7, 2026