General (ICAO)

AIRAC (Aeronautical Information Regulation And Control) is the system defined in ICAO Annex 15 §6.2 / Appendix 4 for the regulated, pre-planned distribution of changes to aeronautical information essential to flight operations. Aim: all airspace users hold identical, validated information by the effective date.

Core principle: Certain "critical" data may only become effective on specified effective dates — the AIRAC effective dates.

AIRAC cycle:

Fixed 28-day cycle, harmonised worldwide.
Effective dates fall on a Thursday at 00
UTC.
13 AIRAC cycles per year.
Publication deadline (§6.2.1): AIRAC amendments must reach users at least 28 days before the effective date (for routine: 56 days) — for major changes with special impact 56 days lead time, in special cases up to 84 days.

What is promulgated via AIRAC (Appendix 4):

AIP amendments with operational impact (changes to procedures, airspace, frequencies, runways),
Establishment / relocation / decommissioning of navigation aids,
New routes, new procedures, new airspace,
Permanent obstacles.

Difference from NOTAM: Non-AIRAC short-notice or unforeseen changes are distributed by NOTAM — AIRAC handles planned, calendar-locked changes.

AIRAC AIP Amendment vs. AIRAC AIP Supplement:

AMDT = permanent AIP change, replaces pages.
SUP = temporary AIP change (typically 3 months–1 year), separate document.

Europe (EASA / EU)

EU-wide harmonisation via Regulation (EU) 2017/373 Annex VI (Part-AIS). An AIRAC calendar is published by EUROCONTROL and is identical EU-wide with the ICAO calendar.

Germany (national)

Responsible: DFS, operating the AIRAC AMDT process for German AIP. AIRAC effective dates are published in AIP GEN 3.1 and the DFS AIRAC calendar.