Aeronautical Information Services

Every flight is planned on information that someone else has collected: runway lengths, radio frequencies, airspace boundaries, danger areas, approach procedures, the crane put up last week beside the final approach. The aeronautical information service (AIS) of each State gathers that information, checks it and publishes it in a standard set of documents, so a pilot preparing a flight to any ICAO Contracting State knows where to look and in what form the answer will come.

The Standards are in ICAO Annex 15, Aeronautical Information Services, with the detailed procedures in PANS-AIM (Doc 10066). Each State is responsible for its own service, which it may provide jointly with other States or delegate to an agency, provided the Standards are met. One principle decides where an item is published: information of lasting character goes in the AIP, operationally significant changes wait for a common AIRAC date, long temporary changes go in AIP Supplements, and short-term or urgent information that cannot wait for the cycle goes out by NOTAM.

Annex 15 and the aeronautical information products

Since the restructured 16th edition of Annex 15, applicable from November 2018, aeronautical information is provided as aeronautical information products and associated services. The products are:

• the Aeronautical Information Publication (AIP), including its amendments and supplements;
• Aeronautical Information Circulars (AICs);
• aeronautical charts;
• NOTAM;
• digital data sets.

The services include distribution and pre-flight information. Older textbooks group the printed elements as the Integrated Aeronautical Information Package (IAIP): the AIP with its amendment service, AIP Supplements, NOTAM and pre-flight information bulletins, AICs, and checklists and lists of valid NOTAM. The term still appears in exam questions.

Two conventions run through every product. Times are in UTC. Since 1 January 1998, published latitudes and longitudes have been referenced to the World Geodetic System 1984 (WGS-84), the datum used by satellite navigation.

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The AIP: GEN, ENR and AD

The AIP is a publication issued by or with the authority of a State and containing aeronautical information of a lasting character. Commercial products such as Jeppesen's reproduce it in a convenient form, but the AIP remains the primary, authoritative source. It has three parts, which a State may publish in one or more volumes:

GEN 1.7 is where a State lists its differences from ICAO Standards and Recommended Practices, as Article 38 of the Chicago Convention requires (see Chicago Convention and ICAO). The French GEN 1.7, for example, notes that French national aerodrome rules still base the aerodrome code letter on both wingspan and outer main gear wheel span, which ICAO no longer does.

Each aerodrome entry in AD follows a fixed numbering, so the same item is always in the same place. In the French AIP, AD 2.6 gives the rescue and fire fighting level, AD 2.10 the aerodrome obstacles, AD 2.12 the runway physical characteristics, AD 2.13 the declared distances and AD 2.14 the approach and runway lighting (see aerodrome physical characteristics).

AIP amendments and supplements

Permanent changes are published as AIP Amendments (AMDT), which replace pages or add new ones. Amendments are numbered serially, and every amended page shows its publication date; in the UK, changed text is marked by a vertical black line in the page margin. Operationally significant permanent changes are issued as AIRAC AIP Amendments, which take effect on an AIRAC date: the pages of the French AIP carry references such as "AIRAC AMDT 01/26".

AIP Supplements (SUP) carry temporary changes: those of long duration, three months or more, and information of short duration that needs extensive text or graphics. They are printed on special pages, preferably yellow, so that they stand out, and are kept in the AIP as long as any of their content remains valid. The UK files them with the GEN part. A permanent change is never published as a Supplement.

The AIRAC cycle

AIRAC (Aeronautical Information Regulation And Control) is a system of common effective dates at intervals of 28 days. Changes that need charts, procedures and navigation databases to be amended at the same moment everywhere, such as new airspace, a changed frequency or a new approach procedure, are published so that they take effect on one of these dates. The rules are:

• AIRAC information is distributed at least 42 days before the effective date;
• where major changes are planned and more notice is desirable, publication 56 days before the effective date should be used;
• once in force, the information should not be changed again for at least another 28 days.

For example, 3 September 2026 and 1 October 2026 are consecutive AIRAC dates. A change taking effect on 1 October 2026 had to be distributed by 20 August 2026 at the latest.

The same 28-day rhythm drives the navigation database. An FMS stores the current and the next cycle, so the new data is already loaded when the date arrives, and an RNP approach may not be flown from a database that has expired, because the coded procedure may have changed at the cycle boundary (see flight management system). The FAA publishes its Terminal Procedures on a 56-day cycle, two AIRAC periods, with a change notice at 28 days.

When an AIRAC Amendment or Supplement is published, a trigger NOTAM draws attention to it. For a permanent change it remains valid for 14 days after the change takes effect; for a temporary change it lasts as long as the change itself.

Aeronautical Information Circulars

An Aeronautical Information Circular (AIC) carries information that does not qualify for inclusion in the AIP and is not suitable for a NOTAM: advisory, explanatory or administrative material. AICs are issued in printed form and numbered serially within each calendar year, and it is each pilot's responsibility to keep up with the current ones.

The UK colour-codes its AICs by subject, a favourite exam question:

NOTAM

A NOTAM (Notice to Airmen) is a notice distributed by telecommunication, mainly over the Aeronautical Fixed Telecommunication Network (AFTN), containing information on the establishment, condition or change of any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations. Whenever possible it is issued at least 24 hours in advance. Typical NOTAM report a navigation aid out of service for a short period, a temporary danger area, a runway closure or a new obstacle near an approach path.

There are three types of NOTAM message: NOTAMN (new information), NOTAMR (replaces an earlier NOTAM) and NOTAMC (cancels one). Each carries a series letter and a number, such as A1234/24. The old division into Class I (telecommunication) and Class II (post) is no longer used.

A NOTAM changes the plan, not just the briefing. Planning is based on what will be available at the estimated time of arrival, so an aid notified as unserviceable at that time is planned as unavailable, and the minima used are those of the approach that will actually be flown. A NOTAM withdrawing the only instrument approach can make an otherwise suitable aerodrome unusable as an alternate (see alternate aerodromes).

SNOWTAM and ASHTAM

A SNOWTAM is a special series NOTAM reporting the condition of the runway surface: snow, slush, ice, frost, standing water and associated conditions. Since 4 November 2021 it follows the ICAO Global Reporting Format (GRF). For each third of the runway it gives a runway condition code (RWYCC) from 6 (dry) to 0, the per cent coverage, the depth of loose contaminant and a plain-language description. A SNOWTAM is valid for at most 8 hours, and a new one is issued with every new runway condition report. The format it replaced allowed 24 hours and included a braking action code 9 (unreliable), which no longer exists. How crews use the codes is covered in wet and contaminated runways.

An aerodrome closed by snow was once signalled by the abbreviation SNOCLO appended to the METAR. That practice ended with the GRF, and closures now reach crews by NOTAM and SNOWTAM.

An ASHTAM is a special series NOTAM for volcanic activity and volcanic ash. The state of the volcano is summarised by the aviation colour code, from green (normal) to red (eruption imminent or under way with significant ash), explained in volcanic ash.

Pre-flight information bulletins

A pre-flight information bulletin (PIB) is a presentation of current NOTAM information of operational significance, prepared before flight for the route and aerodromes requested. It does not replace the AIP, which holds the permanent information, nor the meteorological documentation, which is supplied separately (see meteorological services and briefings). Reading it is where a pilot finds the closed runway, the withdrawn navigation aid or the suspended approach procedure.

AIP entries and NOTAM use standard abbreviations for hours of service, listed in GEN 2.2:

A PPR aerodrome, or service, may be used only with permission obtained in advance. On Jeppesen en-route charts, PPR beside a route arrow means that ATC permission is required before flying the route in that direction.

The FAA system: AIM, Chart Supplement and FDC NOTAM

Besides its ICAO-format AIP, the FAA publishes other products that US pilots use every day. The Aeronautical Information Manual (AIM) explains basic flight information and ATC procedures, while the rules themselves are in 14 CFR. The Chart Supplement holds the airport data: runways, lighting, frequencies and the frequency used for pilot-controlled lighting. In ICAO documents the same letters, AIM, stand for aeronautical information management, the subject of PANS-AIM.

The FAA renamed the NOTAM "Notice to Air Missions" in 2021 and returned to "Notice to Airmen" in February 2025. Its main NOTAM categories are:

• NOTAM (D): navigation aids, airports, runways, taxiways, lighting and obstacles, introduced by keywords such as RWY, TWY, APRON, AD, OBST, NAV, COM, SVC and AIRSPACE;
• FDC NOTAM: regulatory notices from the Flight Data Center, such as amendments to instrument procedures and charts, temporary flight restrictions and other airspace restrictions;
• military NOTAM, for military airports and navigation aids.

A typical NOTAM reads !DEN 09/047 DEN RWY 17L/35R CLSD 2609221300-2609230200: runway 17L/35R at Denver closed from 1300 UTC on 22 September 2026 to 0200 UTC the next day, the times being ten-digit groups in the form YYMMDDHHMM. Runway surface condition is reported in a FICON NOTAM, which gives a runway condition code for each third of the runway, the US counterpart of the SNOWTAM.

Under 14 CFR 91.103 the pilot in command must become familiar with all available information concerning the flight, and FDC NOTAM are part of it: between chart editions, raised minima, unusable navigation aids and suspended procedures are issued as FDC NOTAM.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.