Horizontal reference system
1. Name/designation of datum
All published geographical coordinates indicating latitude and longitude are expressed in terms of the World Geodetic System - 1984 (WGS-84) geodetic reference datum.
2. Area of application
The area of application for the published geographical coordinates coincides with the area of responsibility of the Aeronautical Information Service, i.e. the entire territory of the Republic of Bulgaria as well as the airspace over the high seas encompassed by the Sofia Flight Information Region in accordance with the regional air navigation agreement.
3. Use of an asterisk to identify published geographical coordinates
An asterisk (*) will be used to identify those published geographical coordinates which have been transformed into WGS-84 coordinates but whose accuracy of original field work does not meet the requirements in ICAO Annex 11, Chapter 2 and ICAO Annex 14, Volumes I and 11, Chapter 2. Specifications for determination and reporting of WGS-84 coordinates are given in ICAO Annex 11, Chapter 2 and in ICAO Annex 14, Volumes I and
II, Chapter 2.