A service established within the defined area of coverage responsible for the provision of aeronautical information/data necessary for the safety, regularity and efficiency of air navigation.
Source: ICAO Annex 15
ICAO Annex 15 specifies that each Contracting State must provide an aeronautical information service (AIS) or delegate this to an appropriate non-governmental agency.
The object of AIS is to ensure the flow of information/data necessary for the safety, regularity and efficiency of international air navigation. Such information, which includes the availability of air navigation facilities and services and the procedures associated with them, must be provided to flight operations personnel, as well as the ATS units responsible for flight information service and the services responsible for pre-flight information. The role and importance of this data changed significantly with the implementation of area navigation (RNAV), required navigation performance (RNP), airborne computer based navigation systems and data link systems. Corrupt or erroneous aeronautical data can potentially affect the safety of air navigation. It is therefore important that this data is provided in a standard and uniform format.
Aeronautical information is handled differently depending on its urgency, operational significance, scope, volume and the length of time it will remain valid and relevant to users. It may vary widely in terms of the duration of its applicability. For example, information related to airports and its facilities may remain valid for many years while changes in the availability of those facilities (for instance, due to construction or repair) will only be valid for a relatively short period of time. The urgency attached to information may also vary, as well as the extent of its applicability in terms of the number of operators or types of operations affected by it. Information may be lengthy or concise or include graphics.
Annex 15 specifies that aeronautical information be published as an Integrated Aeronautical Information Package. It is composed of the following elements:
Significant changes are to be notified well in advance so as to provide the recepients with enough time (at least 28 days) to familiarize themselves. This is done using the aeronautical information regulation and control (AIRAC) system. It is based on specific dates at 28 day intervals. Implementation dates other than AIRAC effective dates is not to be used for pre-planned operationally significant changes requiring cartographic work and/or for updating of navigation databases. If possible, the use of dates that occur between 21 December and 17 January for introducing significant changes should be avoided as this period coincides with public holidays in large parts of the world.