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
121.321-1 Compliance with Requirements of § 121.321, Operations in Icing

Using visible moisture and temperature as a means for the flightcrew to know when the airframe ice protection system (IPS) must be activated.

Active ANM-100 2011-08-04