Naval History and Heritage Command

Serial number and bureau number are synonymous terms for the identifying numbers assigned to individual naval aircraft. The earliest system was a letter-number combination which segregated the aircraft by manufacturer (or designer) and general type. As this scheme developed, the letter “A” was used with Curtiss hydroaeroplanes, “B” for Wright type hydroaeroplanes, “C” for Curtiss flying boats, “D” for Burgess flying boats, and “E” for Curtiss amphibian flying boats. Sequential numbers beginning with one, were assigned to each set of aircraft. That scheme was replaced by AH numbers which were assigned aircraft in service. A system of construction numbers was then initiated to identify aircraft on order. The two coexisted for some 15 months when the service numbers were abandoned.

The Early Designation Systems are as follows:

The First System from 1911–1914
A-1 Curtiss hydroaeroplane (originally an amphibian)
A-2 Curtiss landplane, rebuilt as hydroaeroplane. It was again rebuilt as a short-hulled flying boat variously described as OWL for over-water-land or as a Bat boat, and was fitted with wheels for use as an amphibian. This was recorded in the aircraft log for November 25, 1913: “title by order of Captain Chambers [was] changed [to] El.”
A-3 Curtiss hydroaeroplane, received summer of 1912.
A-4 Curtiss (or Curtiss type) hydroaeroplane
B-1 Wright landplane, converted to hydroaeroplane
B-2 Wright type hydroaeroplane, built from spares, October 1912
B-3 Wright type hydroaeroplane, built from spares, October 1913
C-1 Curtiss flying boat
C-2 Curtiss flying boat
C-3 Curtiss flying boat
C-4 Curtiss flying boat
C-5 Curtiss flying boat
D-1 Burgess Co. & Curtis flying boat
D-2 Burgess Co. & Curtis flying boat
E-1 OWL or short hulled amphibious flying boat (see A-2)

The Second Designation System, 1914–1916

AH designations

General Order No. 88 of 27 March 1914 listed the corresponding designations between the above designations and the new system: “The aeroplanes now in the service are hereby designated as follows:

New Designation Old Designation

AH-1 A-1
AH-2 A-2
AH-3 A-3
AH-4 B-1
AH-5 B-2
AH-6 B-3
AB-1 C-1
AB-2 C-2
AB-3 C-3
AB-4 C-4
AB-5 C-5
AB-6 D-1
AB-7 D-2
AX-1 E-1”

Despite the phrase, “now in the Service,” the A-1, B-1, B-2 and probably the D-1 had ceased to exist before the order was issued. Other records show AH-2 as redesignation for A-4.

The designation of follow-on aircraft was as follows:
AH-7 Burgess-Dunne hydroaeroplane
AH-8 Curtiss hydroaeroplane
AH-9 Curtiss hydroaeroplane
AH-10 Burgess-Dunne hydroaeroplane
AH-11 Curtiss hydroaeroplane
AH-12 Curtiss hydroaeroplane
AH-13 Curtiss hydroaeroplane
AH-14 Curtiss hydroaeroplane
AH-15 Curtiss hydroaeroplane
AH-16 Curtiss hydroaeroplane
AH-17 Curtiss hydroaeroplane
AH-18 Curtiss hydroaeroplane

The Five Numbering Systems for the Aircraft History Cards

Construction numbers began with A-51 and, as serial numbers or bureau numbers, ran through A-9206 after which the letter “A” was dropped although sequential numbering continued through 9999. A second series of four digit numbers began with 0001 and ran through 7303. The last number in this series was assigned in December 1940. Beginning in 1941 a series of five digit numbers, beginning with 00001 was adopted and numbers were assigned through 99999, with 99991-100000 cancelled. A sixth digit numbering system was then added beginning with 100001 and is still in use. To summarize, the five major numbering systems are as follows:

A-51 to A-9206
9207 to 9999 (the A prefix was dropped) 
0001 to 7303 
00001 to 100000 (99991-100000 were cancelled)
100001 to present (still in use but with many modifications)

There are several major exceptions to the assignment of numbers in the six digit numbering system. In the 1960s a block of six digit numbers, beginning with 00, were assigned to the DASH vehicle (Drone Antisubmarine Helicopter). The original designation for the unmanned helicopter was DSN. Production models of the DSN were designated QH-50C and QH-50D. All of these helos had six digit bureau numbers that began with 00. The double zeros were part of the bureau number. These numbers obviously do not fit into the regular six digit numbering system that began with 100001. Documentation has not been found that explains why the normal six digit numbering system was not employed for these aircraft.

The other major exception to the normal sequential assignment of bureau numbers in the six digit system involves numbers beginning with 198003 and ranging up to 999794. This group of six digit numbers is not sequentially assigned. Almost all of the aircraft in this group of numbers were acquired by the Navy from the Army, Air Force, or other organizations, not directly from the manufacturer. There appears to be no logical sequence or reasoning for the assignment of these six digit numbers. It is believed that some of the numbers may have been derived by modifying the Air Force aircraft numbering system. However, this is only conjecture since there is no documentation to verify this explanation.

Aside from the very sizable overlap stemming from the numbering schemes, the same number was never used on more than one aircraft. During the planning and contracting processes, however, numbers were often assigned to aircraft that were never obtained. Sometimes, but by no means always, these cancelled numbers were reassigned to other aircraft.

The basic sources used in compiling the following list include a master “Serial List of Designating Numbers for Naval Aircraft” prepared by the aircraft records office in the Bureau of Aeronautics It was typed on twelve 17 1/2 inch by 21 1/2 inch pages and numbered consecutively 0 through 11. It was probably put in that form in 1935 when the first significant handwritten emendations appeared. Page 0 covered the pre-1916 schemes and pages 1 through 11 began with A-51 and ran through all four digit serials. For later aircraft, primarily those in the six digit system, the bureau number listing was compiled by using the “List of Serial Numbers Assigned Navy Aircraft” developed by the Aviation Statistics Office of DCNO (Air) and by reviewing the Aircraft History Card microfilm collection.

The compilations have been cross-checked against the compilation in William T. Larkins, U.S. Navy Aircraft 1921-41; a compilation made by William H. Plant, Librarian, Naval Air Systems Command; and a more comprehensive listing compiled by Jack Collins, a historian and specialist in bureau numbers. Monthly and quarterly reports on the status of aircraft production, Aircraft History Cards, and the Aircraft Strike Listing were used in reconciling discrepancies.

One problem is that interpretations do not show in the final list. In addition, the compiler makes no claim to infallibility in transcribing long lists of numbers and, as a result, may have unwittingly introduced errors not in the original compilations.