Temporal reference system
Co-ordinated Universal Time (UTC) is used by air navigation services and in publications issued by the Aeronautical Information Service. Reporting of time is expressed to the nearest minute.
In the AIP and associated publications, the expression "summer period" will indicate that part of the year in which "daylight saving time" is in force. The other part of the year will be named the "winter period". Daylight saving time in the Republic of Bulgaria is UTC plus 3 hours. The "summer period" will be introduced every year on the last Sunday in March at 0100 UTC and it will cease on the last Sunday in October at 0100 UTC. Times applicable during the "summer period" are given in brackets. Local time in the Republic of Bulgaria is UTC plus 2 hours.
The beginning of the day is designated as 0000 and 2359 for the end of the day.