The AIRAC cycle explained.

The problem AIRAC solves

Aeronautical information is constantly changing. A new instrument approach is designed, an airway is realigned, a control zone is enlarged, a VOR is decommissioned, a frequency is reassigned. Each of these changes has to reach every pilot, dispatcher, avionics database and chart in the affected airspace — and it has to reach them all at the same moment.

Imagine if each state introduced its changes whenever it happened to finish them. A pilot flying internationally would face a different effective date in every country, charts and databases from different suppliers would update on different days, and an aircraft could be flying an approach that one document said was current and another said was withdrawn. The result would be confusion and risk.

AIRAC removes that chaos by imposing a single, shared rhythm. Every state agrees to make its planned, operationally significant changes effective only on common, internationally fixed dates. Everyone changes together, on a date known long in advance, so the whole system stays synchronised.

The 28-day cycle and effective dates

The AIRAC cycle is 28 days long. That length is deliberate: 28 days is exactly four weeks, so an effective date always falls on the same day of the week — a Thursday — which simplifies planning and distribution.

Because the year is not an exact multiple of 28 days, there are 13 AIRAC cycles per year (13 × 28 = 364 days, leaving one or two days each year). The dates are published by ICAO years ahead, so every operator and data supplier knows precisely when each future cycle begins.

Each cycle is commonly identified by year and number — for example "cycle 2605" for the fifth cycle of 2026. Aircraft navigation databases, electronic charts and flight-planning systems all carry the AIRAC identifier of the data they contain, so it is easy to confirm which cycle a database belongs to and whether it is the current one.

The key idea: an AIRAC effective date is not "a date a change happens to land on". It is a date chosen from a fixed global calendar specifically so that changes can be grouped onto it.

What changes on an AIRAC date

An AIRAC effective date is when a batch of planned, operationally significant changes all come into force together. Typical AIRAC changes include:

• Instrument flight procedures — new or amended departures (SIDs), arrivals (STARs), approaches, and the minima associated with them.
• Airspace — changes to the lateral or vertical limits of control zones, terminal areas, control areas, and the classification of airspace.
• Route structure — new, realigned or withdrawn airways and ATS routes, and changes to reporting points and waypoints.
• Navigation aids — commissioning, decommissioning, relocation or frequency changes of VORs, NDBs, DMEs and ILS facilities.
• Communication frequencies — reassignment of ATC, approach, tower and information-service frequencies.
• Aerodrome data — significant changes to runways, declared distances, lighting and other published aerodrome characteristics.
• Restricted, prohibited and danger areas — establishment, changes to dimensions, or withdrawal of special-use airspace.

Not every change goes through AIRAC. Only changes that are planned and operationally significant are handled this way. Urgent changes, and temporary ones, are issued as NOTAMs instead — the AIRAC cycle is too slow for those.

The cutoff and publication lead time

The defining feature of AIRAC is not just the common dates — it is the deliberate lead time between publishing a change and the change taking effect.

The standard rule is that AIRAC information is published and distributed so it reaches recipients at least 28 days before the effective date. For major changes — those requiring substantial work by operators, such as a significant redesign of airspace or routes — the lead time is extended to at least 56 days.

This lead time exists so that everyone downstream has time to act before the change goes live:

• Chart publishers can produce, print and distribute updated charts.
• Navigation-database suppliers can code, validate and release the new data.
• Airlines can update procedures, brief crews and amend their documentation.
• Pilots can study an upcoming change before they have to fly it.

Working backwards from the lead time, a state has an internal cutoff date — the latest point at which it can submit a change for a given cycle. Miss the cutoff and the change waits for the next cycle 28 days later. The exact submission deadlines are administrative and should be confirmed against ICAO guidance and national procedures.

How a pilot stays current

From the cockpit, AIRAC compliance reduces to one principle: fly with the data that is effective on the day you fly. Practically:

• Check the AIRAC date of every chart and database you use. Paper or electronic charts carry an effective date or cycle identifier; the flight management system or navigation app displays the cycle of its loaded database.
• Update on schedule. Chart and database subscriptions are issued per AIRAC cycle. Load the new cycle so it is active on its effective date — not before, not after.
• Never fly on an expired navigation database. An out-of-cycle database may contain a withdrawn procedure, a wrong frequency or an obsolete waypoint. This is a real and recurring cause of error.
• Mind cycle boundaries. If a flight crosses midnight UTC into a new AIRAC date, be aware that the effective information changes during the operation. Plan around the transition.
• Read the AIP amendments for the cycle. Knowing a database changed is not the same as knowing what changed. Review the AIP amendment and any associated Trigger NOTAMs.
• Combine with the NOTAM check. AIRAC tells you the planned baseline. NOTAMs tell you the temporary and urgent deviations from it. You need both.

How AIRAC ties to the AIP and chart databases

AIRAC is the timing mechanism; the AIP and chart databases are what it times.

The Aeronautical Information Publication (AIP) is a state's authoritative reference for its airspace, aerodromes, procedures and services. The AIP is kept current through amendments. Significant, planned amendments are designated AIRAC AIP Amendments and take effect only on AIRAC dates — that is precisely how a planned change to the AIP reaches operators in a synchronised way. Less significant or non-AIRAC information is updated through ordinary amendments and supplements.

To signal that an AIRAC AIP Amendment is coming into force, a state issues a Trigger NOTAM — a brief NOTAM whose only job is to point to the amendment and its effective date. The Trigger NOTAM does not contain the change itself; it draws attention to it.

Chart and navigation databases are derived from the AIP. Suppliers take each cycle's AIP amendments, code them, validate them and release a database tagged with that AIRAC cycle. When you load a current cycle, you are loading a processed snapshot of the AIP as it will be on that effective date. This is why the cycle identifier on your database matters: it is the link back to a specific, dated state of the official information.

Putting it together: a planned change flows from a state's decision, through the AIRAC cutoff and lead time, into an AIRAC AIP Amendment, is flagged by a Trigger NOTAM, is coded into chart and navigation databases, and finally — on its fixed effective date — becomes the information every pilot uses, all at the same moment. The exact AIRAC schedule and amendment arrangements for the Kingdom should be verified against the current AIP-KSA.