ISO 3166-2:BG ISO 3166-2:BG ISO 3166-2:BG is the entry for Bulgaria in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1. Currently for Bulgaria, ISO 3166-2 codes are defined for 28 districts. Each code consists of two parts, separated by a hyphen. The first part is , the ISO 3166-1 alpha-2 code of Bulgaria. The second part is two digits (01–28). The codes are assigned in Bulgarian alphabetical order. Subdivision names are listed as
Aircraft registration being extended, leaving aircraft from both SARs with registration marks of only four characters, as opposed to the norm of five. Aircraft registration Every civil aircraft must be marked prominently on its exterior by an alphanumeric string, indicating its country of registration and its unique serial number. This code must also appear in its Certificate of Registration, issued by the relevant National Aviation Authority (NAA). An aircraft can only have one registration, in one jurisdiction. In accordance with the Convention on International Civil Aviation (also known as the Chicago Convention), all civil aircraft must be registered with a national aviation