Aviation glossary
ICAO
International Civil Aviation Organization — a UN agency based in Montreal that issues international civil aviation standards.
ICAO (International Civil Aviation Organization) was established by the 1944 Chicago Convention and today has 193 member states. It publishes the Annexes — from Annex 1 (personnel licensing) through Annex 6 (operations) and Annex 11 (air traffic services) to Annex 19 (safety management). ICAO standards are not directly enforceable but member states implement them into national law (in the EU through EASA). ICAO also assigns four-letter aerodrome codes (LKHK) and three-letter operator call signs.