Belgian aircraft registration and serials

1913 – 1928

The first use of aircraft registrations was based on the radio callsigns allocated at the London International Radiotelegraph Convention (1912). The format was a single letter prefix followed by four other letters (like A-BCDE).^[1] The major nations operating aircraft were allocated a single letter prefix but minor countries had to share a single letter prefix but were allocated exclusive use of the first letter of the suffix.^[1] Belgium was not considered a major operator of aircraft and was allocated the prefix and first letter suffix O-B. When the conference allocated the same prefix it made sure that they were in different parts of the world, the other user of the O prefix was Peru and they were allocated O-P.^[1] The first allocation was O-BEBE to a Fokker D.VII on 1 March 1920.^[1]

1929 – current

At the 1927 International Radio-Telegraph Conference, new radio callsigns were allocated to Belgium, comprising ON, OO, OP, OQ, OR, OS and OT.^[1] In 1928 the International Convention of Air Navigation re-allocated the aircraft registration prefix to align with these radio callsigns.^[1] Belgium could use all or any letter groups that had been allocated as radio callsigns and in 1929 the prefix OO- was selected for civilian aircraft, while a number of Belgian military aircraft have used the prefix OT-.^[1][2] On 1 March 1929 a number of existing civilian aircraft were migrated across to the new register, many retaining much of their earlier registration; for instance the Caudron C.27 previously registered O-BAFW became OO-AFW.^[3]

Registrations are sometimes re-cycled. One of the first aircraft on the revised register was OO-AJT, initially allocated to a Stampe et Vertongen RSV.26/100 in March 1929. This same registration was used again from 1952 on a Miles M.14 Hawk Trainer III, and re-issued for a third time in 1958 on a Zlin Z.226T Trener.^[3][4][5]

Use

Some of the blocks of registrations have had a reserved usage and these include:

• OO-BAA to OO-BZZ used mainly for balloons
• OO-CAA to OO-CZZ used for the Belgian Congo 1934-1960
• OO-YAA to OO-ZZZ used mainly for gliders
• OO-01 to OO-499 used for homebuilt aircraft

Belgian Air Force

When the Belgian Air Force was re-formed in 1946 individual aircraft were allocated serial numbers in either a one or two letter prefix followed by a one or two digit number. The first allocations were mainly single letters (for example A-1 was an Auster AOP.6) but sometimes a second letter was used to distinguish variants, for example NA-1 was an Avro Anson I and NB-1 was an Anson II.^[6]

In the 1950s the first letter started to be used as a role prefix, for example FX-01 was a Lockheed F-104G Starfighter classified as a Fighter.^[6]

An Aero Commander 560F was operated for royal flights between 1961 and 1973 without a serial number but display its radio callsign OT-CWB instead.^[6] Similarly, there have been Douglas C-47B transports "registered" OT-CWA, OT-CWG and OT-CNR, and a Sikorsky S-58 helicopter "registered" OT-ZKP.

Belgian Army

In 1954 the Belgian Army formed its own aviation element and serial numbers were allocated in the form OL-A01, the OL for Observation Leger (light observation), the letter for the type and the number for each individual aircraft. In 1974 the OL prefix was dropped.^[6]

Belgian Navy

The Belgian Navy have operated a number of shipborne helicopters which were allocated serials with single letter prefix although the radio callsigns were also painted on the aircraft in a similar format to registrations.^[6]