AD/AC-SNOW/1 - Mixture Control Lever Quadrant - Modification - CANCELLED

What this does This document scraps a 42-year-old aircraft safety rule that required owners of specific crop-dusting planes (Ayres Thrush and Snow Commander series) to mark their fuel mixture control levers with "LEAN" and "CUT-OFF" positions.

Who it affects Owners and operators of Ayres Thrush and Snow Commander aircraft. However, there is no action required—this directive simply removes an old rule that everyone has already complied with.

Why it matters The original rule from 1966 was designed to prevent engine problems by ensuring pilots could clearly see the fuel mixture settings. Because all affected aircraft have been modified over the past four decades, the Civil Aviation Safety Authority has cancelled the directive as it is now redundant. This is housekeeping to clear obsolete rules from the books.