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to the Convention on
International Civil Aviation
Aircraft Nationality and Registration Marks
How are aircraft classified and identified, and how can you tell aircraft nationality?
These are but two of the questions answered in the briefest ICAO Annex, which deals with aircraft nationality and
registration marks, and, in a separate table, classifies aircraft by how they maintain sustained flight in the air.
The Annex is based on Articles 17 to 20 of the Chicago Convention. The ICAO Council adopted the first Standards
concerning this issue in February 1949, based on recommendations from the first and second sessions of the
Airworthiness Division, held in 1946 and 1947 respectively. Since then only four amendments have been made to the
Annex. The latest edition is the fifth one, issued in 2003.
The first amendment introduced the definition of a "rotorcraft", and modified requirements related to the location of
nationality and registration marks on wings. The second amendment redefined the word "aircraft", the use of which
became effective in 1968; it also implemented a decision that all air-cushion-type vehicles, such as hovercraft and other
ground-effect machines, should not be classified as aircraft.
Since Article 77 of the Convention permits joint operating organizations, Amendment 3 was introduced to define
"Common Mark", "Common Mark Registering Authority" and "International Operating Agency", to enable aircraft of
international operating agencies to be registered on other than a national basis. The determining principle of the related
provisions is that each international operating agency must be assigned a distinctive common mark by ICAO, this being
selected from a series of symbols included in the radio call signs allocated by the International Telecommunication
Union (ITU).
The fourth amendment, adopted in 1981, introduces provisions related to registration and nationality marks for
unmanned free balloons.
The fifth amendment, adopted in 2003, introduces a new requirement for the Certificate of Registration to carry an
English translation if issued in a language other than English.
The Annex sets out procedures for selection by ICAO Contracting States of nationality marks from the nationality
symbols included in the radio call signs allocated to the States of Registry by the ITU.
It sets standards for the use of letters, numbers and other graphic symbols to be used in the nationality and registration
marks, and spells out where these characters will be located on different types of airborne vehicles, such as lighter-thanair
aircraft and heavier-than-air aircraft.
This Annex also calls for the registration of the aircraft, and provides a sample of this certificate for use by ICAO
Contracting States. This certificate must be carried in the aircraft at all times, and an identification plate, bearing at least
the aircraft's nationality, or common mark and registration mark, must be affixed in a prominent position to the main
Years of considerable effort permit the classification of aircraft to be as simple as possible, and yet encompass as many
types of flying machines as the human mind can devise.