AIRAC

An acronym (Aeronautical Information and Regulation and Control) signifying a system (and associated NOTAM, or notices to airmen) that tries to advance notification, based on common effective dates, of circumstances that necessitate changes in operating practices. In part 1 of the AIRAC NOTAM, information about the establishment and withdrawal of, and premeditated significant changes to (including operational trials), the items mentioned therein are given. This may include:
i. Horizontal and vertical limits, regulations, and procedures applicable to flight information regions; control areas and control zones; ATS (air traffic services) routes; advisory routes; permanent danger; prohibited and restricted areas, including type and periods of activity when known; and ADIZ (air defense identification zone).
ii. Position, frequencies, call signs, known irregularities, and maintenance periods of radio navigation aids and communications facilities.
iii. Aerodrome lighting and beacons, obstructions, and snow plans.
iv. Holding and approach procedures, arrival and departure procedures, noise abatement, and any other pertinent ATS (air traffic services) procedures.
v. Meteorological facilities and procedures.
vi. Part 2 includes the establishment and withdrawal of, and premeditated significant changes to the position, height, and lighting of navigational obstructions; hours of service of aerodromes, facilities and services, customs, immigration and health services; temporary danger, prohibited and restricted areas and navigational hazards, military exercises and mass movement of aircraft.