thumb|upright=1.14|A [[Van's Aircraft RV-7 displaying registration G-KELS. The G prefix denotes a civil aircraft registered in the United Kingdom.]]

thumb|Geographic map of registration prefixes

An aircraft registration is a code unique to a single aircraft, required by international convention to be marked on the exterior of every civil aircraft. The registration indicates the aircraft's country of registration, and functions much like an automobile license plate or a ship registration. This code must also appear in its Certificate of Registration, issued by the relevant civil aviation authority (CAA). An aircraft can only have one registration, in one jurisdiction, though it is changeable over the life of the aircraft.

In accordance with the Convention on International Civil Aviation (also known as the Chicago Convention), all civil aircraft must be registered with a civil aviation authority (CAA) using procedures set by each country. Every country, even those not party to the Chicago Convention, has a national aviation authority

(NAA) whose functions include the registration of civil aircraft. An aircraft can only be registered once, in one jurisdiction, at a time. The NAA allocates a unique alphanumeric string to identify the aircraft, which also indicates the nationality (i.e., country of registration) of the aircraft, and provides a legal document called a Certificate of Registration, one of the documents which must be carried when the aircraft is in operation.

The registration identifier must be displayed prominently on the aircraft. 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.

Most nations' military aircraft typically use tail codes and serial numbers. Military aircraft most often are not assigned civil registration codes. However, government-owned non-military civil aircraft (for example, aircraft of the United States Department of Homeland Security) are assigned civil registrations.

Although each aircraft registration identifier is unique, some countries allow it to be re-used when the aircraft has been sold, destroyed or retired. For example, N3794N is assigned to a Mooney M20F. It had been previously assigned to a Beechcraft Bonanza (specifically, the aircraft in which Buddy Holly was killed). An individual aircraft may be assigned different registrations during its existence. This can be because the aircraft changes ownership, jurisdiction of registration, or in some cases for vanity reasons.

Choice of aircraft registry

thumb|Shortly after the ending of [[United States sanctions|US trade embargo, early Vietnam Airlines Western-supplied aircraft were registered in an overseas jurisdiction (such as Seychelles, as denoted by the S7 prefix) during the 1990s]]

Most often, aircraft are registered in the jurisdiction in which the carrier is resident or based, and may enjoy preferential rights or privileges as a flag carrier for international operations.

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 financing institution may be reluctant to allow the aircraft to be registered in the carrier's home country (either because it does not have sufficient regulation governing civil aviation, or because it feels the courts in that country would not cooperate fully if it needed to enforce any security interest over the aircraft), and the carrier is reluctant to have the aircraft registered in the financier's jurisdiction (often the United States or the United Kingdom) either because of personal or political reasons, or because they fear spurious lawsuits and potential arrest of the aircraft.

International standards

thumb|left|A [[Japan Airlines Boeing 747-400 displaying Japanese registration JA8089]]

The first use of aircraft registrations was based on the radio callsigns allocated at the London International Radiotelegraphic Conference in 1913. The format was a single letter prefix followed by four other letters (like A-BCDE). The major nations operating aircraft at that time were allocated a single letter prefix. Smaller countries had to share a single letter prefix, but were allocated exclusive use of the first letter of the suffix.

Each alphabetic letter in the suffix can have one of 24 discrete values, while each numeric digit can be one of 10, except the first, which can take on only one of nine values. This yields a total of 915,399<!-- 1–5 digits = 9+90+900+9000+90000=99999, 1L+1−4D=24×9999=239976, 2L+1−3D=24×24×999=575424. Total=915,399 --> possible registration numbers in the namespace, though certain combinations are reserved either for government use or for other special purposes.

  • S = state
  • X = experimental

For example, N-X-211, the Ryan NYP aircraft flown by Charles Lindbergh as the Spirit of St. Louis was registered in the experimental category.

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, N4YZ is, on the one hand, a Cessna 206 registered to a private individual in Melba, Idaho, while, on the other hand, is also issued to an Amateur Radio operator in North Carolina. Since an aircraft registration number is also used as its call sign, this means that two unrelated radio stations can have the same call sign.

Decolonisation and independence

The impact of decolonisation and independence on aircraft registration schemes has varied from place to place. Most countries, upon independence, have had a new allocation granted – in most cases this is from the new country's new ITU allocation, but neither is it uncommon for the new country to be allocated a subset of their former colonial power's allocation. For example, after partition in 1947, India retained the VT designation it had received as part of the British Empire's Vx series allocation, while Pakistan adopted the AP designation from the newly allocated ITU callsigns APA-ASZ.

When this happens it is usually the case that aircraft will be re-registered into the new series retaining as much of the suffix as is possible. For example, when in 1929 the British Dominions at the time established their own aircraft registers, marks were reallocated as follows:

  • Canada: G-Cxxx to CF-xxx, then expanded to C-Fxxx, C-Gxxx, and then C-Ixxx in 1974.
  • Australia: G-AUxx to VH-Uxx, then immediately expanded to all VH-xxx marks. As of 2022, the last three (3) characters will include numerals, e.g. VH-8AA.
  • New Zealand: G-NZxx to ZK-Zxx, then immediately expanded to all ZK-xxx marks.
  • Newfoundland: G-Cxxx (with Canada) to VO-xxx, then re-merged with the Canadian register in 1949 to CF-xxx.
  • South Africa: G-UAxx to ZU-Axx, then expanded to all ZU-xxx marks, then again to current ZS-xxx, ZT-Rxx, and ZU-xxx allocations.

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.

Registration prefixes and patterns by countries

See also

  • Aircraft lease
  • Flight number
  • Belgian aircraft registration and serials
  • Swiss military aircraft serials
  • ITU prefix
  • United Kingdom aircraft registration
  • United Kingdom military aircraft registration number
  • United States military aircraft serials
  • United States military tail code
  • List of aircraft registration prefixes
  • List of aircraft by tail number

References

  • Searchable worldwide registration database
  • Aruba Aircraft Register
  • Australian Aircraft Register
  • Austrian Aircraft Register
  • Belgian Aircraft Register
  • Brazilian Aircraft Register
  • British Aircraft Register
  • Canadian Aircraft Register
  • Croatian Aircraft Register
  • Danish Aircraft Register
  • Dutch Aircraft Register
  • Dutch Historic Aircraft Registers
  • Finnish Aircraft Register
  • French Aircraft Register
  • Guatemalan Aircraft Register
  • Guernsey 2-REG Register
  • Indian Aircraft Register
  • International Registry of Mobile Assets, pursuant to the Cape Town Treaty
  • Irish Aircraft Register
  • Isle of Man Aircraft Register
  • Latvian Aircraft Register
  • Lebanese Aircraft Register
  • Luxembourg Aircraft Register
  • Maltese Aircraft Registration
  • New Zealand Aircraft Register
  • Norwegian Aircraft Register
  • Singapore Aircraft Register
  • South African Aircraft Register
  • Swedish Aircraft Register
  • Swiss Aircraft Registry
  • United States Aircraft Registry
  • Article 20 of the Convention on International Civil Aviation
  • Annex 7 to the Convention on International Civil Aviation
  • Supplement to Annex 7 of the Convention on International Civil Aviation