Some countries sell their AIP data or have relationships with commercial entities which sell this data or place copyright restrictions on the use of their data. Data for these countries has been compiled from free sources in order to allow the Great Circle Mapper to be available as a free resouce.
Other countries have freely available AIP data which have yet to be incorporated into the Great Circle Mapper's database. This data is being incorporated as time and resources permit.
AIPs are effective on a fixed, 28-day cycle known as an Aeronautial Information Regulation And Control (AIRAC) cycle. Some countries, including the United States, use a 56-day double AIRAC cycle. Updates are distributed well in advance of the cycle's effective date to allow time for systems to be updated with the new data before it takes effect.
For more information, see the Aeronautical Information Publication article at Wikipedia.
Information on this site may not be accurate or current and is not valid for flight planning or navigation. No warranty of fitness for any purpose is made or implied. Flight planning and navigation should only be done using official charts.
Copyright © 1996-2013
Karl L. Swartz.
All rights reserved.