ICAO is the over-riding part to aviation world wide, working towards a standardised system world wide.
The Convention on International Civil Aviation, also known as the Chicago Convention, established the International Civil Aviation Organization (ICAO), a specialized agency of the United Nations charged with coordinating and regulating international air travel. The Convention establishes rules of airspace, aircraft registration and safety, and details the rights of the signatories in relation to air travel. The Convention also exempts air fuels from tax.
The document was signed on December 7, 1944 in Chicago, U.S., by 52 signatory states. It received the requisite 26th ratification on March 5, 1947 and went into effect on April 4, 1947, the same date that ICAO came into being. In October of the same year, ICAO became a specialized agency of the United Nations Economic and Social Council(ECOSOC). The Convention has since been revised eight times (in 1959, 1963, 1969, 1975, 1980, 1997, 2000 and 2006).
In aircraft accidents, the most important is:
Annex 13 – Aircraft Accident and Incident Investigation, which in Australia is ATSB’s bailiwick.