The International Civil Aviation Organization (ICAO), an agency of the United Nations, codifies the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. Its headquarters are located in the Quartier International of Montreal, Canada.
The ICAO Council adopts standards and recommended practices concerning air navigation, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation. In addition, the ICAO defines the protocols for air accident investigation followed by transport safety authorities in countries signatory to the Convention on International Civil Aviation, commonly known as the Chicago Convention. See NTSB, TSB, AAIB, BFU, and BEA.
The ICAO should not be confused with the International Air Transport Association (IATA), a trade organization for airlines also headquartered in Montreal, or with the Civil Air Navigation Services Organisation (CANSO), an organization for Air Navigation Service Providers (ANSP's) with its headquarters at Schiphol airport in the Netherlands.
The 9th edition of the Convention on International Civil Aviation includes modifications from 1948 up to year 2006 . The ICAO refers to its current edition of the Convention as the statute, and designates it as ICAO Doc 7300/9.
The Convention has 18 Annexes. These Annexes are listed by title in the article Convention on International Civil Aviation.
The ICAO defines an International Standard Atmosphere (also known as ICAO Standard Atmosphere), a model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere. This is useful in calibrating instruments and designing aircraft.
The ICAO standardizes machine-readable passports worldwide. Such passports have an area where some of the information otherwise written in textual form is written as strings of alphanumeric characters, printed in a manner suitable for optical character recognition. This enables border controllers and other law enforcement agents to process such passports quickly, without having to input the information manually into a computer. ICAO publishes Doc 9303, Machine Readable Travel Documents, the technical standard for machine-readable passports. A more recent standard is for biometric passports. These contain biometrics to authenticate the identity of travellers. The passport's critical information is stored on a tiny RFID computer chip, much like information stored on smartcards. Like some smartcards, the passport book design calls for an embedded contactless chip that is able to hold digital signature data to ensure the integrity of the passport and the biometric data.
ICAO is also responsible for issuing alphanumeric aircraft type codes that contain 3 or 4 characters. These codes provide the identification that is typically used in flight plans. An example of this is the Boeing 747 that would use (depending on the variant) B741, B742, B743, etc.
ICAO provides telephony designators to aircraft operators worldwide. These consist of the three-letter airline identifier and a one- or two-word designator. They are usually, but not always, similar to the aircraft operator name. Thus the identifier for Aer Lingus is EIN and the designator is Shamrock, while Japan Airlines International is JAL and Japan Air . Thus, a flight by Aer Lingus numbered 111 would be written as "EIN111" and pronounced "Shamrock One One One" on the radio, while a similarly numbered Japan Airlines flight would be written as "JAL111" and pronounced "Japan Air One One One".
ICAO maintains the standards for aircraft registration ("tail numbers"), including the alphanumeric codes that identify the country of registration.
The ICAO has seven regional offices serving nine regions:
Emissions from domestic aviation are included within the Kyoto targets agreed by countries. This has led to some national policies such as fuel and emission taxes for domestic air travel in the Netherlands and Norway respectively. Although some countries tax the fuel used by domestic aviation, there is no duty on kerosene used on international flights. (Aviation Environment Federation )