Aviation glossary
AIRAC
Aeronautical Information Regulation and Control — a fixed 28-day cycle used worldwide to publish aeronautical changes simultaneously.
AIRAC (Aeronautical Information Regulation and Control) is the globally agreed schedule for publishing significant aeronautical changes (new procedures, frequency changes, airspace amendments). Each new edition becomes effective on the 28th day at the same moment around the world so pilots, controllers and navigation databases have time to prepare. The publication lead time is typically 28 or 56 days.