There were a number of other designation systems associated with airborne hardware.

Last updated: 1 February 2015

Balloons and Airships

Air Force

Balloons and airships of the Air Force’s predecessors were not considered aircraft but rather as individual ships. No designation system was used and no serials were assigned although balloons and airships were classified by types and numbering within these types was used for identification.

A          A Class

AC        Advanced Training, C Class

D          D Class (ex Navy)

E          E Class

F          F Class

J          J Class (ex Navy)

M         M Class  (Kite balloons)

OA       Observation, A Class

OB       Observation, B Class

R          Rigid Airship (not used)

RN        Reconnaissance, Non-Rigid

RS        Reconnaissance, Semi-Rigid

TA        Training, A Class

TC        Training, C Class

TE        Training, E Class

TF        Training, F Class

Table 1: Army balloon classifications


US Navy

Until 1954 Navy airships were classified as Z (for Zeppelin) class ships and separate from aircraft.

The following classifications were used:


ZF                    Free balloon

ZH                    Search and rescue balloon

ZK                    Kite balloon

ZN                    Training balloon

ZP                    Patrol balloon

ZR                    Rigid airship

ZRCV               Rigid airship/Aircaft carrier

ZRN                  Rigid airship/training

ZRS                  Rigid airship/Scout

ZS                    Scout balloon

ZT                    Training balloon

Table 2: Balloon/airship classifications


The rigid airships were also assigned names:

ZR‑1                 USS Shenandoah

ZR‑2                 Short R-38 crashed 24 August 1921, before delivery – not named

ZR‑3                 USS Los Angeles

ZRS‑4               USS Akron

ZRS‑5               USS Macon

Table 3: Airship names

The USS Shenandoah (ZR-1) was based on the design of the German L-49, a World War I high altitude bomber which had been forced down intact in France in October, 1917. It was constructed  during 1922 and 1923 with parts fabricated at the Naval Aircraft Factory in Philadelphia, and final assembly at the Lakehurst Naval Air Station in New Jersey.

The ZR-1 was 680’4”, 207.37 m long, with a diameter of 79’8”, 24.28 m. It carried six Packard 6-cylinder engines of which five were mounted in individual power cars attached to the hull, and one mounted at the rear of the control gondola. The sixth engine was removed in 1924. The max. speed was 60 mph, 97 km/h.

The first flight was on 4 September 1923 and the airship entered service on October 10, 1923. It crashed on 3 September 1925 at Noble County, OH


ZR-2 was bought from Britain where construction had been started on it as the R38 before cancellation. It was bought in October 1919, and flew for the first time on 23 June 1921 but crashed on 23 August 1921 at Hull, UK, before the US Navy could take delivery of it and did not officially receive its US designation, though it was painted in accordance of its planned Navy designation.

Built by Short and powered by 6 Sunbeam Cossack III engines, it had a length of 695’, 211.84 m, a diameter of 85’6”, 26.06 m, and a max. speed of 71 mph, 114 km/h. The name it would have received in US Navy service is not known and may never have been assigned.


The USS Los Angeles (ZR-3) was built in Germany by the Zeppelin Company as LZ-126.

On 12 October 1924 it flew from Friedrichshafen, Germany, across the Atlantic Ocean where it arrived at NAS Lakehurst on 15 October 1924. The ZR-3 remained in service until 1939 when it was withdrawn from use. It had a length of 658’, 200.56 m and a diameter of 90’6”, 27.58 m. It was powered by 5 Maybach engines and had a max. speed of 76 mph, 122 km/h.


The USS Akron (ZRS-4) and USS Macon (ZRS-5) were designed for long-range scouting in support of fleet operations. Often referred to as flying aircraft carriers, each ship carried F9C-2 Curtiss Sparrowhawk biplanes which could be launched and recovered in flight, greatly extending the range over which the Akron and Macon could scout the open ocean for enemy vessels.

Both were designed and built by the Goodyear-Zeppelin Corporation, a joint venture and patent sharing arrangement between the Luftschiffbau Zeppelin and the Goodyear Tire and Rubber Corporation. The contract was awarded on 16 October 1928.

The USS Akron flew for the first time on 23 September 1931 and was lost in a storm on 4 April 1933 off New Jersey.

The USS Macon flew for the first time on 21 April 1933 and was lost on 12 February 1935 off California.

The ZRS-4 and -5 were identical and had a length of 785’, 239.27 m, diameter of 132’11”, 40.51 m and were fitted with 8 Maybach VL-2 engines. The max. speed was 60 mph, 97 km/h.

USS Akron

USS Akron (Source: US Navy)


From 1935 to 1942 the US Navy studied concepts of rigid airships to be used as an aircraft carrier and a training airship. They were to carry nine aircraft which were to be based on the Douglas BT-1, and would probably have received the ZRCV and ZRN designations.


Other balloons were serialled in the aircraft system and have subsequently discussed as undesignated aircraft.

From 1954 balloons were treated as aircraft and have been discussed with the appropriate aircraft designations.



From 1962 balloons/airships were classified as aircraft in the Z‑series. They have been discussed with the appropriate designations.


Other equipment
External stores

External stores, incl. armament used by the US Armed Forces is designated in a number of series consisting of three letters followed by a sequential number.

The first two letters indicate the type of equipment, the third letter is U = Unit.

The first two letters are:

BB                    Explosive items

BD                   Simulated bombs

BL                    Bombs and mines

BR                    Bomb racks and shackles

BS                    Munition stabalizing and retarding devices

CB                    End item cluster bombs

CC                    Actuator cartridges

CD                   Clustered munitions

CN                    Miscellaneous containers

DS                   Target detecting devices

FM                   Munitions fuses

FS                    Munitions fuse safety/arming devices

FZ                    Fuse related items

GA                   Aircraft guns

GB                   Guided bombs

GF                    Gun related items

GP                   Podded guns

GU                   Miscellaneous guns

KA                    Munitions clustering hardware

KM                   Kits

LA                    Aircraft installed launchers

LK                    Ammunition links

LM                    Ground based launchers

LU                    Illumination units

MA                   Miscellaneous armament items

MD                   Miscellaneous simulated munitions

MH                   Munitions handling equipment

MJ                    Munitions counter measures

ML                    Miscellaneous munitions

MT                    Mounts

PA                    Munitions dispensing devices‑external

PD                   Leaflet dispensers

PG                   Ammunition

PW                   Internal dispensers

RD                   Dummy rockets

RL                    Rockets

SA                    Gun‑Bomb‑Rocket sights

SU                    Stores suspension and release items

TM                    Miscellaneous tanks

TT                     Test items

WD                   Warheads

WT                   Training warheads

Table 3: Equipment codes

‘Iron’ bombs are not included in this designation series, instead they are identified by a MK = mark, followed by a number. At times special versions of these bombs may have had external stores designations.

The AN/ALQ designation refers to externally stored electronic equipment.


Electronic equipment

Electronic equipment is designated by a three letter code in which the first letter indicates the mobility, the second letter its characteristics and the third letter its purpose. Each three letter code is followed by a sequential number.

The first letters are

A                      Airborne

B                      Underwater

D                      Piloteless carrier

F                      Fixed

G                      Ground

K                      Amphibious

M                     Mobile

P                      Portable

S                      Surface ship

T                      Ground transportable

U                      Utility

V                      Vehicle mounted


The second letters are

A                      Light/heat/radiation sensor

B                      Pigeon

C                      Carrier (wire)

F                      Photographic

G                      Teletype/telegraph

I                       Interphone, public address

K                      Telemeter

L                      Meteorological

N                      Sound (in air)

P                      Radar

Q                      Sonar

R                      Radio

S                      Special types

T                      Telephone

V                      Visual

X                      Television


The third letters are

A                      Auxiliary

B                      Bombing

C                      Communications

D                      Direction Finder

G                      Gun/searchlight

H                      Recording

M                     Maintenance

P                      Photo/sound reproducing

Q                      Special types

R                      Receiving

S                      Search/detection

T                      Transmitting

W                     Remote control

X                      Identification/recognition

Table 4: Electronic equipment


Photographic equipment

Photographic equipment is designated by a two letter code in which the first letter indicates the type of equipment and the second letter the purpose of the equipment. Each two letter code is followed by a sequential number.

The first letters are

A                      Picture Using Equipment

B                      Accessories, Attachments and Components for Picture Using Equipment

E                      Picture Processing Equipment

F                      Accessories, Attachments and Components for Picture Processing Equipment

K                      Camera

L                      Accessories, Attachments and Components for Cameras


The second letters are

A                      Reconnaissance (used with “K” and “L” only)

B                      Strike Recording (used with “K” and “L” only)

C                      Aerial Mapping (used with “K” and “L” only)

D                      Scope Recording (used with “K” and “L” only)

E                      Still Picture (used with “K” and “L” only)

F                      Motion Picture (used with “K” and “L” only)

G                      General Purpose (used with “K” and “L” only)

H                      Processing Machine (used with “E” and “F” only)

J                      Developer (used with “E” and “F” only)

K                      Washer (used with “E” and “F” only)

L                      Dryer (used with “E” and “F” only)

M                     Miscellaneous (used with “B”, “F” and “L” only)

N                      Printer (used with “E” and “F” only)

P                      Projector (Still Picture) (used with “A” and “B” only)

Q                      Projector (Motion Picture) (used with “A” and “B” only)

R                      Viewing Device (used with “A” and “B” only)

S                      Set or System

Table 5: Photographic equipment


Drone control systems

In 2003 the letter D was introduced for flight control systems for unmanned aerial vehicles (in the Q series). Known designations are

MD-1A and B                General Atomics

RD-2A and B                 Northrop Grumman

MD-3A and B                Teledyne


Support Equipment

Aeronautical support equipment has been indentified by a three letter code ending in U or K. Further details can be found at http://www.designation_systems.net.


Satellite launch vehicles have sometimes been designated as LV or SLV for Launch Vehicle and Space Launch Vehicle.

SLV-1               Vought Scout

SLV-2               Douglas Thor

SLV-3               Convair Atlas

SLV-4               Martin Titan II

SLV-5               Martin Titan III

Table 6: Space launch vehicles


Later the designation SB for Space Booster was introduced.

SB-1                 General Dynamics Atlas E

SB-2                 General Dynamics Atlas 2

SB-3                 McDonnell Douglas Delta II

SB-4                 Martin Marietta Titan II

SB-5                 Martin Marietta Titan IV

SB-6                 Martin Marietta Titan 34D

SSB-7               Boeing IUS

SSB-8               Lockheed Centaur

SSB-9               McDonnell Douglas PAM D-II

SSB-10             Martin Marietta Transtage

ASB-11             Orbital Sciences Pegasus

Table 7: Space Boosters


Examples of early satellite designations include KH, RH and VH whilst the letters P and S have also been used.

The KH designations have been used for military reconnaissance satellites. Although ‘Keyhole’ is often cited as the meaning of the acronym KH, it is suspected that the meaning of this military designation is different. This suspicion is supported by the use by the US Air Force of the letter K to designate aircraft cameras (such as KA-59 for a 1965 camera designed for medium altitude reconnaissance missions), whilst the meaning of the letter H may be found in the apparent designations RH and VH and the associated designations VS and VU. The two latter are for non-satellite detection systems for surface and sub-surface nuclear explosions. Since the letters S and U have been used in other designation system to indicate surface and sub-surface, H may mean satellite borne. Note that this assumption is not in anyway supported by references.


NS-7B Navstar (Source: Rockwell)

In app. 1985 a separate series of satellite designations was introduced in which the letter S was preceded by a mission indicator, being E = communications, L = surveillance, N = Navigation and W = weather.

WS-1    General Electric DMSP 5D-2

WS-2    DMSP 6 (cancelled)

LS-3     TRW DSP


ES-5     General Electric DSCS III

LS-6     BSTS

NS-7     Rockwell Navstar

ES-8     Lockheed Milstar

LS-9     Space Surveillance and Tracking System (cancelled)

LS-10    Space Based Radar Satellite System (cancelled)

S-11     not assigned to avoid confusion with XSS-11 satellite

S-12     not assigned to avoid confusion with XSS-12 satellite

S-13     not assigned

ES-14   Boeing Wideband Global Satcom

LS-15    Ball SBSS (?), Launch Detection/Space Surveillance Satellite

LS-16    Lockheed Martin SBIRS (?), Launch Detection/Space Surveillance Satellite

ES-17   Lockheed Martin AHEF

Table 8: Satellites

In app. 1999 the designation MS-1A was used for the Military Spaceplane System and Space Maneuver Vehicle as a development of the X-33, X-34, X-37, X-40 and X-41.


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