United Kingdom military aircraft registration number

Military aircraft operated by government agencies and civilian contractors (for example QinetiQ, AirTanker Services, Babcock International) are sometimes also assigned registration numbers from this system.

The registration numbers are allocated at the time the contract for supply is placed with the aircraft manufacturer or supplier.

[3] The first example of this practice was an early 1937 order for two-hundred Avro Manchester bombers; which were allotted the registration numbers L7276-7325, L7373-7402, L7415-7434, L7453-7497, L7515-7549, and L7565-7584, covering a range of 309 possible serial registration numbers, and thus making it difficult for an enemy to estimate true British military aircraft strength.

By 1940, the registration number Z9978 had been allocated to a Bristol Blenheim, and it was decided to restart the sequence with a two-letter prefix, starting at AA100.

An exception to this rule was a Douglas Skyraider AEW1 which received the UK serial WT097, which incorporated the last three digits of its US Navy Bureau Number 124097.

[a] During the Second World War, RAF aircraft carrying secret equipment, or that were in themselves secret, such as certain military prototypes, had a '/G' suffix added to the end of the registration number, the 'G' signifying 'Guard', denoting that the aircraft was to have an armed guard at all times while on the ground, examples include: W4041/G, the prototype Gloster E.28/39 jet powered by the Whittle jet engine; LZ548/G, the prototype de Havilland Vampire jet fighter; or ML926/G, a de Havilland Mosquito XVI experimentally fitted with H2S radar.

For example, the first Royal Air Force Boeing C-17 Globemaster III was given the registration number ZZ171 in 2001,[5] and a batch of Britten-Norman Defenders for the Army Air Corps (AAC) were given registration numbers in the ZGnnn range in 2003 (the last ZG serial being allocated more than 14 years previously).

The under-wing registration numbers, originally specified so that in case of unauthorised low flying, affected personnel could report the offending aircraft to the local police force, have not been displayed since the 1960s, as by then jet aircraft speeds at low level had made the likelihood of a person on the ground being able to read, and thus report them, increasingly remote.