Just in time for winter in the U.S., the FAA in October published a revised version of its Advisory Circular on in-flight icing. The new AC 91-74B, Pilot Guide: Flight in Icing Conditions, updates the previous version, which was last issued in 2007, and consolidates a related guidance document, AC 91-51A, Effect Of Icing On Aircraft Control And Airplane Deice And Anti-Ice Systems, which last was updated in 1996. Its purpose is to “provide pilots with a convenient reference guide on the principal factors related to flight in icing conditions and the location of additional information in related publications.”
The new icing AC offers substantial detail for pilots on how to plan for, avoid and deal with in-flight icing in its 63 pages, including pre-flight information and consequences of operating an ice-laden aircraft. Additionally, the AC discusses how aircraft icing certification has changed over the years, including for the FAR Part 23 airplanes many of us fly.
