Aircraft registration

Every country, even those not party to the Chicago Convention, has an NAA[clarification needed] whose functions include the registration of civil aircraft.

[3] Most countries also require the registration identifier to be imprinted on a permanent fireproof plate mounted on the fuselage in case of a post-fire/post-crash aircraft accident investigation.

Carriers in emerging markets may be required to register aircraft in an offshore jurisdiction where they are leased or purchased but financed by banks in major onshore financial centres.

The first use of aircraft registrations was based on the radio callsigns allocated at the London International Radiotelegraphic Conference in 1913.

Although initial allocations were not specifically for aircraft but for any radio user, the International Air Navigation Convention held in Paris in 1919 (Paris Convention of 1919) made allocations specifically for aircraft registrations, based on the 1913 callsign list.

The markings have been amended and added to over the years, and the allocations and standards have since 1947 been managed by the International Civil Aviation Organization (ICAO).

Annex 7 to the Chicago Convention describes the definitions, location, and measurement of nationality and registration marks.

While the Chicago convention sets out the country-specific prefixes used in registration marks, and makes provision for the ways they are used in international civil aviation and displayed on aircraft, individual countries also make further provision for their formats and the use of registration marks for intranational flight.

Many other nations register gliders in subgroups beginning with the letter G, such as Norway with LN-Gxx and New Zealand with ZK-Gxx.

This yields a total of 915,399 possible registration numbers in the namespace, though certain combinations are reserved either for government use or for other special purposes.

There is a unique overlap in the United States with aircraft having a single number followed by two letters and radio call signs issued by the Federal Communications Commission to Amateur Radio operators holding the Amateur Extra class license.

For example, when in 1929 the British Dominions at the time established their own aircraft registers, marks were reallocated as follows: Two oddities created by this reallocation process are the current formats used by the Special Administrative Regions of the People's Republic of China, Hong Kong and Macau, both of which were returned to PRC control from Britain in 1997 and Portugal in 1999 respectively.

Hong Kong's prefix of VR-H and Macau's of CS-M, both subdivisions of their colonial powers' allocations, were replaced by China's B- prefix without the registration mark being extended, leaving aircraft from both SARs with registration marks of only four characters, as opposed to the norm of five.