AIRAC

AIRAC (Aeronautical Information Regulation and Control) is a system established by ICAO for advance notification of changes to aeronautical information. It operates on a fixed 28-day cycle, ensuring that all aviation stakeholders worldwide implement changes simultaneously.

Key features:

• Changes take effect on pre-determined dates (every 28 days)
• Information must be distributed at least 42 days before the effective date (28 days notice + 14 days distribution)
• Covers changes to procedures (SIDs, STARs, approaches), airspace, airways, and navigation data

The AIRAC cycle is critical for:

• FMS database updates: Airlines and operators update their Flight Management System databases every 28 days
• Chart revisions: Approach plates, en-route charts, and airport diagrams are updated on AIRAC dates
• AIP amendments: Permanent changes to Aeronautical Information Publications follow the AIRAC cycle

The AIRAC system has been in operation since 1964 and is fundamental to the safety and standardization of international aviation.