USAAS / USAAC / USAAF / USAF Mission Design Series (Pre-1962)

North American B-25J-20-NC "Mitchell" (World War II)

1909-1919 System (Aeronautical Division of the U.S. Army)

On August 1, 1907, the Aeronautical Division of the U.S. Army was created, although the first aircraft was not accepted until August 2, 1909. During the period from 1909 to 1919, there was no organized system of designation for Army aircraft; all aircraft were operated by the designations of individual manufacturers. An example of this is the 1911 Wright B "Flyer" shown below.

1911 Wright Modified B "Flyer"

1919-1924 System (United States Army Air Service)

In 1919, the Aeronautical Division became independent from the Army and was named the Army Air Service (USAAS). At this time a designation system was adopted utilizing 15 basic "mission symbols", along with other miscellaneous symbols, followed by a "design number". This system was officially adopted after the Army Re-organization Act of June 4, 1920, which made the USAAS a component of the Army. New mission symbols were added, modified mission and status symbols were introduced, and eventually, the original 15 became obsolete. The original 1919 designation included the Basic Mission Symbol, the Design Number, and the Series Letter, i.e. Curtiss PW-8A, Boeing PW-9, Huff-Daland LB-3, etc. As you can see, the 1919 system was rather complicated and cumbersome. A new system was then introduced in 1924. During this period, the name of the aircraft manufacturer was not included in the basic designation system. It was common practice to print the manufacturer's name along with the aircraft designation on the fuselage or the rudder of the aircraft.

The early designation systems included only three elements: (1) the"Basic Mission" symbol, (2) the "Design Number", and (3) a "Series Letter". A code or symbol for the manufacturer of the aircraft was not included. Instead the name of the manufacturer was spelled out on the aircraft. Examples of the early designation system is shown below.

Curtiss PW-8A
Aeroplane Photo Supply (APS) Photo No. 631

1924-1948 System (United States Army Air Corps and United States Army Air Force)

The USAAS became the U.S. Army Air Corps (USAAC) under the Air Corps Act of July 2, 1926 and the General Headquarters of the Air Force (GHQAF) was formed on March 1, 1935 to alleviate some of the responsibilities of the USAAC. On June 20, 1941, U.S. Army Air Forces (USAAF), with the USAAC and the GHQAF as its principal parts. However, GHQAF was discontinued on March 9, 1942. During World War II, many new mission symbols were added, redesignated, overlapped, and discontinued. Thus resuled in many ambiguities and confusions. However, on September 18, 1947, the USAAF became the United States Air Force, and was completely separated from the Army.

North American P-51D-10-NA Mustang

(Status Prefix¹) (Modified Mission²) (Basic Mission³) - (Design Number⁴) (Series Letter⁵) - (Block Number⁶) - (Manufacturer Code⁷)

(1) Aircraft Status Prefix

The status prefix indicates a nonstandard use of an aerospace vehicle, such as test, experimental, prototype, etc. Appears to the immediate left of the modified mission symbol or basic mission symbol for aircraft. Example: North American XB-70A "Valkyrie". Status prefix "X" denotes a B-70 Experimental aircraft.

North American XB-70A "Valkyrie"
Aircraft Status Prefix "X" indicates "Experimental" Status

(1) Status Prefixes
E	Exempt (Bailment to USAAF Contractor)	1946-1947
G	Permanently Grounded	1924 →
R	Restricted	1943-1947
X	Experimental	1925-
Y	Service Test	1928 →
Y1	Aircraft purchased with "F-1" funds instead of USAAC appropriation
Z	Obsolete	1928

(2) Aircraft Modified Mission (Optional)

The modified mission symbol identifies modifications to the basic mission of an aircraft. Appears to the immediate left of the basic mission symbol. Example: KC-97L, Modified Mission "K" identifies a C-97L modified for "tanker" role.

Boeing KC-97L "Stratofreighter"
Aircraft Modified Mission Symbol "K" indicates "Tanker" Configuration

(2) Modified Mission Symbols
C	Transport	1943-1962
D	Director (Drone Controller)	1948-1962
F	Photographic	1945-1947
G	Carrier	1948
K	Ferret	1944-1947
K	Tanker	1949-1962
M	Medical	1951-1952
P	Passenger Transport Only	1948-1962
Q	Radio Controlled Drone	1948-1962
R	Reconnaissance (Photographic)	1948-1962
S	Search and Rescue	1948-1962
T	Trainer	1943-1962
U	Utility	1943-1942
V	Staff (VIP Transport)	1945-1962
W	Weather	1948-1962

(3) Basic Mission

The basic mission identifies the primary function and capability of an aircraft and is the initial symbol assigned to that series. For standard vehicles (e.g., bombers, fighters), it appears to the immediate left of the "design number" separated by a dash. EXAMPLE: P-51D. Basic Mission "P" denotes pursuit.

North American P-51D-25-NA "Mustang"
Basic Mission Symbol "P" indicates "Pursuit" Configuration

Basic Mission Symbols
A	Aerial Target	1940-1941 (became PQ - Aerial Target Man Carrying)
A	Amphibian	1948-1962 (formerly OA - Observation Amphibian)
A	Attack	1924-1927 (became B - Bomber)
AG	Assault Glider	1942-1944
AT	Advanced Trainer	1925-1947 (became T - Trainer)
B	Bomber	1925-1962
BC	Basic Combat	1936-1940 (became AT - Advanced Trainer)
BG	Bomb Glider	1942-1944
BLR	Bomb, Long Range	1935-1936 (became B - Bomber)
BQ	Bomb, Controllable	1942-1945
BT	Basic Trainer	1930-1947 (became T - Trainer)
C	Cargo	1925-1962
CG	Cargo Glider	1941-1947 (became G - Glider)
CQ	Target Control	1942-1947 (became D - Director (Drone Controller) Modified Mission)
F	Fighter	1948-1962 (formerly P - Pursuit)
F	Photographic	1930-1947 (became R - Reconnaissance (Photographic) Modified Mission)
FG	Fuel Glider	1930-1947
FM	Fighter, Multiplace	1936-1941
G	Glider	1948-1962
G	Gyroplane	1935-1939 (became O - Observation)
G	Gyroplane	1935-1939 (became R - Rotary Wing)
GB	Glide Bomb	1942-1947
GT	Glide Torpedo	1942-1947
H	Helicopter	1948-1962 (formerly R - Rotary Wing)
HB	Heavy Bomber	1925-1927 (became B - Bomber)
JB	Jet-Propelled Bomb	1943-1947)
L	Liaison	1942-1962 (formerly O - Observation)
LB	Light Bomber	1924-1932 (became B - Bomber)
O	Observation	1924-1942 (became L - Liaison)
OA	Observation Amphibian	1925-1947 (became A - Amphibian)
OQ	Aerial Target (Model Airplane)	1942-1947 (became Q - Aerial Target)
P	Pursuit	1925-1947 (became F - Fighter)
PB	Pursuit, Biplace	1935-1941
PG	Powered Glider	1943-1947
PQ	Aerial Target (Man Carrying)	1942-1947 (formerly A - Aerial Target)
PQ	Aerial Target (Man Carrying)	1942-1947 (became Q - Aerial Target)
PT	Primary Trainer	1925-1947 (became T - Trainer)
Q	Aerial Target	1948-1962 (formerly OQ - Aerial Target (Model Airplane))
Q	Aerial Target	1948-1962 (formerly OQ - Aerial Target (Man Carrying))
R	Reconnaissance	1948-1962 (formerly F - Photographic)
R	Rotary Wing	1941-1947 (became H - Helicopter)
S	Supersonic / Special Test	1946-1947 (became X - Special Research)
T	Trainer	1948-1962 (formerly AT - Advanced Trainer)
T	Trainer	1948-1962 (formerly BT - Basic Trainer)
T	Trainer	1948-1962 (formerly PT - Primary Trainer)
TG	Training Glider	1941-1947
U	Utility	1952-1962
V	VTOL or STOL	1954-1962
X	Special Research	1941-1947 (formerly S - Supersonic / Special Test)

(4) Design Number

The design number identifies major design changes within the same basic mission. Design numbers run consecutively from "1" to "999" and appears to the immediate right of the basic mission, separated by a dash. EXAMPLE: P-51. Design Number "51" is the 51st MDS requested for an aircraft with a pursuit mission under the system.

Lockheed P-38L-5-LO "Lightning"
Design Number "38" indicates the 38th "Pursuit" Configuration

(5) Series Number

The "Series Number" identifies the production model of a particular design number and later models representing major modifications that significantly alter the aircraft's components or change of logistics support of the vehicle. Consecutive series symbols, starting with "A", appear to the immediate right of the design number. To avoid confusion, the letters "I" and "O" are not used for this symbol. EXAMPLE: P-47D. Series "D" indicates the forth production model of the P-47. At the end of this series indicator "Z", the next sequence will be to advance the design number to the next consecutive unused number and begin with symbol series "A".

Republic P-47D-30-RA "Thunderbolt"
Series Number "D" indicates the 4th modification to the basic P-47 configuration

(6) Block Number

Block numbers were introduced by the U.S. Army Air Force in World War II to distinguish between minor sub-variants of a specific aircraft variant. They were originally assigned in steps of five, i.e. 1, 5, 10, 15, ..., with the gaps being intended to be used for modifications after production. This was also the rule for block numbers as defined in the first issue of the current designation system in 1962.

Republic F-84F-30-RE "Thunderstreak"
Block Number "30" represents a specific configuration of the F-84F build series

(7) Manufacturer Code Letters

The following two-letter codes were used to identify the manufacturing plant of an aircraft. Like the block numbers, these code letters were introduced by the USAAF during World War II. However, manufacturers' codes were officially dropped from the regulations in 1976.

Curtiss C-46F-1-CU "Commando"
Manufacturer Code Letters "CU" indicated that the aircraft was built by "Curtiss, Buffalo, NY"

1948-1962 System (United States Air Force)

When the USAF was created, a "division of duties" was established that prohibits the Army from operating any fixed wing, jet-powered attack aircraft, or tactical reconnaissance aircraft. The 1924-1948 system remained in use until a new designation system was also modified and adopted by all branches of service on September 18, 1962.

1962 United States Tri-Service Aircraft Designation System

On the 18 September 1962, the United States Department of Defense introduced a unified designation system for the aircraft of the United States armed forces. Prior to this date, each service used their own nomenclature system. The 1962 system was based on the one used by the U.S. Air Force between 1948 and 1962. Since it was introduced the 1962 system has been modified and updated; in 1997 a revised form of the system was released. Almost all aircraft operated by the USAF, United States Navy (USN), United States Coast Guard (USCG) and United States Marine Corps (USMC)) and the United States Army are assigned a designation under this system. Experimental aircraft operated by manufacturers or National Aeronautics and Space Administration (NASA) are also often assigned numbers in the X-series.