Almost every chart, frequency, and procedure you rely on comes from one official document per country, the AIP, and it changes on a clock the whole world keeps in step.
This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.
What the AIP is
The Aeronautical Information Publication (AIP) is the official manual of aeronautical information of a lasting character that is essential to air navigation, published by or under the authority of a State's Aeronautical Information Service (AIS). It is the source of record for the data on your charts and in your navigation database. The framework that every State follows comes from ICAO Annex 15 (Aeronautical Information Services), which is why an AIP from one country is organised much like an AIP from another.
That common structure has three parts:
- GEN (General) carries national rules, units, abbreviations, definitions, and administrative information.
- ENR (En-route) covers airspace, air traffic services, routes, navigation aids, and en-route procedures.
- AD (Aerodromes) holds the details of each aerodrome: charts, runways, lighting, frequencies, and local procedures.
The FAA's national AIP and the UK AIP published through NATS both follow this GEN, ENR, AD layout, because both are built to the same ICAO standard.
Why aeronautical data needs effective dates
Aeronautical data is shared across the whole system: pilots, controllers, chart makers, and navigation-database providers all have to be working from the same version at the same moment. If a new instrument approach, a re-sectorised piece of airspace, or a changed frequency took effect at a random time, some users would have the new data and some the old, which is exactly the situation that causes errors.
The answer is to make planned changes take effect on pre-announced, common dates, published far enough ahead that everyone can prepare. That system is AIRAC, which stands for Aeronautical Information Regulation And Control.
The 28-day AIRAC cycle
Under ICAO Annex 15 and as described on ICAO's AIRAC page, AIRAC establishes a series of common effective dates at intervals of 28 days. Planned, operationally significant changes are timed to one of these dates, so the entire community switches over together. The schedule repeats indefinitely, which is why you will hear pilots and dispatchers refer to "the current AIRAC cycle" by its date or cycle number.
For Europe, EUROCONTROL publishes the AIRAC effective-date schedule and coordinates distribution. The information is sent out well ahead of the effective date, with the objective that recipients hold it at least 28 days before it takes effect, giving providers time to update databases and charts. The AIRAC system is defined by ICAO; EUROCONTROL administers the European schedule rather than originating the rule.
Each cycle carries three dates worth keeping straight, as the ICAO AIRAC schedule sets out: the publication date, when the information is made available; the latest reception date, by which users should hold it (the objective being at least 28 days ahead); and the effective date itself, when the new data becomes valid and the old data is withdrawn. The gap between publication and effective date is deliberate, so that loading the new cycle early is encouraged while using it early is not, because it is simply not valid until its effective date arrives.
How the pieces fit together
Not every change waits for an AIRAC date, and knowing which channel carries which kind of change keeps your briefing honest:
- The AIP itself holds the lasting information.
- An AIP Amendment makes a permanent change, and operationally significant amendments take effect on an AIRAC date so everyone updates together.
- An AIP Supplement carries a temporary change of relatively long duration (weeks or months), such as a runway resurfacing programme.
- A NOTAM carries short-notice or short-duration changes and hazards, as covered in our guide to NOTAMs.
A complete picture means reading across all of them: the current AIP and its amendments for the baseline, supplements for longer temporary changes, and NOTAMs for what has changed since.
Common pitfalls
- Flying an out-of-date database or chart. A navigation database has an AIRAC effective and expiry date; using one past its cycle is using superseded data.
- Confusing the publication date with the effective date. AIRAC material is published ahead of time precisely so you can load it early, but it is not valid until its effective date arrives.
- Assuming the AIP has everything. Short-notice changes live in NOTAMs, not in the AIP, until the next amendment folds them in.
- Mixing cycles across providers. Your charts, your database, and your briefing should all be on the matching current cycle.
In Pilot EFB
Pilot EFB pulls the NOTAMs for your route and helps you work through them by aerodrome and area, which is the short-notice layer that sits on top of the AIP. It is not an AIP, a charting service, or a navigation database, and it is not a certified Electronic Flight Bag, so use the official AIP and a current, in-cycle database as your source of record for charts and procedures. NOTAMs you have already pulled stay readable with no signal, because your device holds what you have saved; fetching the latest issued NOTAMs needs a connection.