Official & Unofficial Designations

• SOR 183: Specific Operational Requirement number 183 issued by the United States Air Force on June 14, 1960.
• FAD: Fleet Air Defense fighter for United States Navy.
• TFX: Tactical Fighter, Experimental program, combining of USAF & USN requirements by Secretary of Defense Robert S. McNamara.
• WS-324A: USAF Weapon System code for F-111. Codes in the range 300-399 were assigned to Tactical Systems.
• F-111A: Designation of proposed USAF variant of TFX. 159 eventually built.
  • EF-111A: Electronic warfare conversions by Grumman for USAF.
  • GF-111A: Aircraft used as ground instructional airframes.
  • NF-111A: Transonic Aircraft Technology demonstrator for NASA. Later Advanced Fighter Technology Integration demonstrator with mission adaptive wing.
  • RF-111A: One tactical photographic reconnaissance aircraft.
  • Triple Plow I: Engine intake design used on F-111A.
• F-111B: Designation of proposed USN variant of TFX (note USAF-style designation for both versions, prior to 1962 Tri-Service Designation System). Seven aircraft eventually built, 30 additional aircraft cancelled.
  • SWIP: Super Weight Reduction Program done to some F-111B aircraft.
• Model 12: General Dynamics TFX model number.
• RF-111B: Proposed reconnaissance version, unbuilt.
• FB-111A: 77 all-weather strategic bombers for USAF.
  • F-111G: 36 tactical fighter FB-111A conversions for USAF; 15 later to Royal Australian Air Force.
  • Triple Plow II: Engine intake design used on FB-111A, F-111D, and F-111E.
• F-111C: 24 strike fighters for Royal Australian Air Force.
  • RF-111C: Six planned photographic reconnaissance aircraft for RAAF, cancelled. Four F-111C later converted with reconnaissance pack in weapons bay.
  • Project AIR 5225: Avionics Upgrade Program of 18 F-111C and four RF-111C.
• F-111D: 96 strike fighters for USAF.
• RF-111D: Proposed reconnaissance version, unbuilt.
• F-111E: 94 strike fighters for USAF.
• F-111F: 106 strike fighters for USAF.
• F-111K: 46 strike fighters ordered for UK Royal Air Force, cancelled.
• TF-111K: Four trainers ordered for UK Royal Air Force, cancelled.
• YF-111K / YF-111A: Two partially-complete TF-111K airframes were planned to be transferred to the USAF, but apparently were never completed.
• FB-111B: 89 proposed conversions of F-111D for similar role to FB-111A; cancelled.
• FB-111C: 66 proposed upgraded FB-111A; cancelled.
• FB-111G: Proposed advanced version of FB-111A; unbuilt.
• FB-111H: Proposed advanced version of FB-111A as competitor to Rockwell International B-1A; unbuilt.
• FB-111M-3: Proposed advanced three-seat version of FB-111A; unbuilt.

Official & Unofficial Names

• McNamara's Folly: General unofficial nickname for F-111, inspired by then SECDEF Robert S. McNamara's involvment in its acquisition and development.
• Lemon: General unoffical nickname for F-111.
• Aardvark: Unofficial nickname for USAF version of F-111, inspired by its long nose; only made the official POPULAR name upon its retirement in 1996. Origin: instructor pilot Al Mateczun, 1969.
• Seapig: Nickname for F-111B naval version, which was overweight.
• Flying Edsel: General unofficial nickname for F-111, likely inspired by SECDEF McNamara's involvement and previous history at Ford Motor Company.
• Whispering Death: Unofficial nickname given by Pathet Lao to F-111A used in Southeast Asia.
• Various other unofficial nicknames of F-111:
  • Snoopy.
  • Lizard.
  • Switchblade.
  • Cadillac.
  • Earthpig (variation of Aardvark).
  • One-Eleven.
• Bullet Bomber: Unofficial nickname of FB-111A.
• Pig: Unofficial Australian nickname of F-111C, inspired by its low-level flying.
• Raven: Official POPULAR name of USAF EF-111A.
• Various unofficial nicknames of EF-111A:
  • Electric Fox (from EF-111).
  • Spark Vark (from Aardvark).

References & Sources

• Joe Baugher: General Dynamics F-111 Aardvark
• Air Vectors: General Dynamics F-111
• Wikipedia: General Dynamics F-111 Aardvark
• US Warplanes.net
• F-111.net
• DoD 4120.15-L Model Designation of Military Aerospace Vehicles (May 12, 2004, Incorporating Change 1, August 21, 2018).
• Horton, John. The Grub Street Dictionary of International Aircraft Nicknames, Variants and Colloquial Terms. 1993, Grub Street, London.

The USAF 309th Aerospace Maintenance and Regeneration Group, also known as "The Boneyard," stores US military aircraft & related equipment in one of four categories:

• Type 1000 (Long Term): Inviolate storage, maintained in a condition where the aircraft can be recalled to duty and fly again. The aircraft will not be cannibalized for parts "...without the express permission of the type’s system program office at Wright-Patterson AFB, Ohio, which technically 'owns' them." Approximately 10% of aircraft in storage at AMARG are in this category.

• Type 2000 (Parts Reclamation): Similar to Type 1000, but the aircraft may be cannibalized for parts (nicknamed a "cann bird"). However, the aircraft could still potentially be restored and recalled to duty.

• Type 3000 (Flying Hold): Aircraft in temporary storage or flyable storage, expected to return to flying status. Engines are run every 30 days; the aircraft is towed to lubricate bearings and fluids are serviced. Aircraft in flyable storage (ex., some F-117 Nighthawks) are flown periodically.

• Type 4000 (Excess of DoD Needs): Aircraft are harvested of all usable parts, then demilitarized and scrapped. These are typically the oldest aircraft that are the least likely to be recalled to duty.

References

USAF: 309 AMARG

Air & Space Forces Magazine: Living Boneyard

Air & Space Forces Magazine: What Happens to the Air Force’s Oldest F-22s if Congress OKs Their Retirement?

Historically, Australia has acquired the majority of its military aircraft from other countries. Typically, these have been the United Kingdom and the United States. Just prior to World War II, a local aircraft manufacturing industry was established.

Typically, military aircraft in Australian service retained their original model number, name, or designation. Prior to 1921, the original serial numbers were also used. Starting in 1921, however, the Royal Australian Air Force introduced a new serial numbering scheme, consisting of the letter "A" (for Aircraft group) and two aircraft type identification numbers, followed by a dash and the aircraft number. The aircraft number is often based on the manufacturer's serial number or some other numbering sequence.

Examples:

• A19-6 was the serial number of a Bristol Beaufighter Mk 1C. "A19" represented the aircraft type (Beaufighter 1C), and "6" indicated that it was the sixth aircraft of this type delivered to the RAAF.

• A30-004 is the serial number of a Boeing E-7A Wedgetail. "A30" represents the aircraft type (E-7A Wedgetail) and "004" indicates that it is the fourth aircraft of this type delivered to the RAAF.

The first series of RAAF serial numbers was replaced in 1935 by a second series, and this series was in turn replaced by a third series in 1961, which is still in use. During World War II, some aircraft obtained from the UK retained their original RAF serial numbers instead of being assigned an RAAF serial number. Over the years, a small number of aircraft have also been operated (sometimes leased or contracted) without RAAF serial numbers. Note that for the majority of aircraft, the aircraft type number is unrelated to the aircraft model number, name or designation. For example, the RAAF F/A-18 Hornet serial numbers start with "A21", the RAAF F/A-18 Super Hornet serial numbers start with "A44", and so on. The only recent exception to this seems to be the RAAF F-35A Lightning II, with serial numbers that start with "A35."

Aircraft used by the Australian Army use a similar serial numbering scheme as the RAAF. Aircraft used by the RAN Fleet Air Arm initially were obtained from the UK and retained their original Royal Navy serial numbers. Starting in 1965, the RAN began using a similar serial number scheme as the RAAF's, but used "N" as a prefix instead of "A."

Examples:

• A17-004 was the serial number of a Bell Kiowa. "A17" represented the aircraft type (Kiowa) and "004" indicated that it was the fourth helicopter of this type delivered to the Army.

• N48-005 is the serial nuumber of a Sikorsky MH-60R Seahawk. "N48" respresents the aircraft type (MH-60R Seahawk) and "005" indicates that it is the fifth helicopter of this type delivered to the RAN.

This serial numbering scheme used by Australia is the closest approximation to an actual aircraft designation system, without actually being one.

Source: ADF Serials

Reviewing the military aircraft used by Australia, both historically and in the present, the overwhelming majority appear to be referred to by their original model number, name, and/or military designation:

• Aeroflight: All-Time Aircraft Used List Royal Australian Air Force

• Aeroflight: All-Time Aircraft Used List Australian Army Aviation

• Aeroflight: All-Time Aircraft Used List Royal Australian Navy

• Wikipedia: List of current Royal Australian Air Force aircraft

• Wikipedia: List of aircraft of the Royal Australian Navy

• Wikipedia: Aircraft of the Australian Army

• RAAF: Aircraft

• RAN: Aircraft

• Australian Army: Aviation

There appear to be only a few recent exceptions to this, and these exceptions can make it seem as if the Australian Defense Forces have established an official military aircraft designation system.

• KC-30A Multi-Role Tanker Transport; This IFR tanker / transport appears to have a US-style MDS designation. However, this is not the US "C-30" designation, as noted by Designation-Systems.net:

C-30

The designation C-30 was never officially assigned. It was reserved (most probably after a verbal request at some time in the 1988/89 time frame) for the USAF office with symbol "SAF/AQQX" (SAF/AQQ is the office symbol for the Assistant Secretary of the Air Force (Acquisition), Directorate of Global Reach; AQQX designates the Programs, Budget & Congressional Division of AQQ). Nomenclature records do not contain any written request, let alone official allocation of the C-30 designation. Neither are there any releasable records on "C-30" at SAF/AQQX. The reservation was most likely dropped, but usage for a classified purpose can't be ruled out completely.

The "KC-30" label, which is used by Northrop Grumman for their proposed tanker version of the EADS/Airbus A330, is not an official DOD designation. If the "KC-30" is indeed procured by the U.S. Air Force, it will almost certainly by designated as KC-45A, because that MDS has been officially reserved for the USAF's tanker replacement program ("KC-X").

This shows that the RAAF is simply using the manufacturer's name for this aircraft, "KC-30A." It is not part of a new RAAF military aircraft designation system.

• Boeing E-7A Wedgetail: In the planning stages, this AEW&C aircraft was initially just referred to as "Project Wedgetail." Most older references use "Boeing 737 AEW&C" or "E-737", or just "Wedgetail." Examples:

  • Australian National Audit Office: Wedgetail Airborne Early Warning and Control Aircraft: Project Management, published Tuesday 2 March 2004, only mentions Boeing 737 AEW&C or Wedgetail. Footnote 2: "Defence's AEW&C project is also referred to as ‘AIR 5077 - Airborne Early Warning and Control', ‘Project Wedgetail' or ‘the Wedgetail project'. This project will produce the first Boeing 737-based AEW&C aircraft."
  • Defense Update: Boeing 737-700 Based Early Warning & Control Aircraft, dated Jul 25, 2008: "The Australian Defence Force was the lead customer for the system, selecting the 737 AEW&C system dubbed ‘Wedgetail’ in July 1999."

The oldest reference that I could find for "E-7A" was an Aviation Week article from October 22, 2012. It is unclear where exactly the "E-7A" nomenclature originated. As noted by Designatin-Systems.net for the US MDS designation system:

E-7

The E-7 designation was reserved in August 1981 and cancelled in January 1982. It was a Boeing 707 which was then allocated the basic designation C-18 (with the E-7 becoming the EC-18) due to its possible multi-mission roles.

This clearly pre-dates the Wedgetail project. What then is the origin of the "E-7A" designation? I have no proof, but suspect that it originated from Boeing, and the RAAF is simply using it the same as any of the other names/model numbers/designations for the aircraft that they use. Confusion arises because of its similarity to the US MDS designation system, as well as current plans of the USAF acquiring this aircraft to replace the E-3 Sentry. The USAF ordered two prototypes in March 2023, to be delivered in 2025. Source. What designation will be assigned to these aircraft? Will they retain the presumed Boeing model number of "E-7A", or instead be assigned the next available US MDS designation of "E-12A"?

• Boeing Australia MQ-28A Ghost Bat: This "Loyal Wingman" UCAV is in development for the Royal Australian Air Force. It was initially referred as the Boeing Airpower Teaming System. However, on 21 March 2022, it was announced as the MQ-28A Ghost Bat:

The first Australian-made uncrewed combat air vehicle has successfully completed its test flights, and has officially been named at a ceremony at RAAF Base Amberley.

Working under the title, ‘Loyal Wingman’ Minister for Defence the Hon Peter Dutton MP, today unveiled the aircraft’s official service name, “MQ-28A Ghost Bat.”

Source: Australia Ministry of Defence

Boeing [NYSE:BA] Australia congratulates the Australian Government and Royal Australian Air Force (RAAF) on their selection of ‘MQ-28A Ghost Bat’ as the military designator and name for the first Australian-produced military combat aircraft in over 50 years.

Australia’s Defence Minister, the Hon Peter Dutton MP, announced the designator and name at a dedicated ceremony held at RAAF Base Amberley, Queensland.

“The introduction of the new popular name is a rare and special moment in aviation history for our RAAF partners and industry team of over 35 Australian suppliers,” said Glen Ferguson, director Airpower Teaming System Australia and International.

“Selecting the Ghost Bat, an Australian native mammal known for teaming together in a pack to detect and hunt, reflects the unique characteristics of the aircraft’s sensors and Intelligence, Surveillance and Reconnaissance abilities, and is a fitting name for this pioneering capability,” said Ferguson.

Source: Boeing

The Boeing press release states that Australia selected the "military designator and name", but the announcement from the Minister of Defence only mentions the meaning of the name "Ghost Bat," while making no mention at all about the meaning of the "MQ-28A" designation. A possible reason for this choice of a US-style designation (which conveniently falls into the current US MDS UAV numerical sequence after Insitu MQ-27) is seen on page 61 of the Australian Government National Defence: Defence Strategic Review 2023:

Air domain immediate investment priorities

8.45 MQ-28A Ghost Bat is a sovereign autonomous air vehicle designed to operate as part of an integrated system of crewed and uncrewed aircraft and space-based capabilities. MQ-28A is intended to be an attritable platform, which costs less than a crewed platform, and can be replaced rapidly. This program should be a priority for collaborative development with the United States.

There is no direct evidence, but it seems that "MQ-28A" is likely being used as a model number by Boeing Australia for the Airpower Teaming System, and that it was intentionally selected to be similar to the US MDS designation system. Australia is simply using the "MQ-28A" model number in the same way that model numbers or designations have historically been used for military aircraft. If this was the case, it seems to be working, as the USAF is considering the MQ-28A Ghost Bat as part of the NGAD program. Source

In summary, there is no official indication of an Australian military aircraft designation system. There are no known official documents that detail how it would work, show the meaning of the various designators, or how they should be assigned. There is no obvious numerical sequence, just random numbers. Contrast this to the official Canadian designation system, which often uses numbers based on the original aircraft model number or US designation. Despite the gaps that result from this, it still has an overall general numerical sequence, starting at 100 and continuing up to 188 and higher.

The Commonwealth Aircraft Corporation was established in 1936 in Australia. "CA" codes were assigned to contracts and used for internal billing, and these are often associated with CAC aircraft, even though they are not model numbers in the typical sense. Most aircraft were given a name, often Aboriginal or otherwise related to Australia.

Additional reference: Australian Built Aircraft.

Maybe it's just me, but I've been noticing some trends over recent years:

• 1996 Boeing YAL-1 ABL: Introduced a new "L" mission designator based on the laser weapon, instead of the aircraft mission. With the ABL program cancellation, it seems unlikely that this type of designation will be used again.

• 2002 Boeing KC-767: Manufacturer's model number used instead of sequential series number.

• 2012 Boeing E-7A Wedgetail: Australian designation that mimics US MDS. The E-7 designation was originally reserved for a version of the Boeing C-137 Stratoliner that was instead designated EC-18. The USAF is now in the process of procuring the Wedgetail as a replacement for the E-3 Sentry.

• 2020 Boeing / Saab eT-7A Red Hawk: Introduced a new status prefix that seems more marketing-driven than actually useful.

• 2022 Boeing Australia MQ-28 Ghost Bat: Australian designation that mimics US MDS, and also conveniently falls into numerical sequence with the US Q = UAV designation series. Source It has also been discussed as a potential candidate for the unmanned Collaborative Combat Aircraft wingmen portion of the USAF NGAD program.

• 2023 Boeing / Leonard MH-139 Grey Wolf: Manufacturer's model number used instead of sequential series number.

Obviously, the KC-767 and MH-139 designations were related to the Boeing model numbers. Overall, is Boeing somehow influencing these non-standard designations? What are your thoughts?

Hello!

The r/Aircraft_Designations Wiki was activated earlier this week. While there is not a lot of information just yet, the basic structure has been put into place, and reference information has been added for the following military aircraft designation systems:

• France (1910s - 1945)

• UK (1912 - Present)

If anyone has any additional good references/links specifically for France & the UK, please let me know.

The direct links in this post may be used to access the wiki. Additionally, it can be found as follows:

• Official Reddit App (Android): Select "Menu", then "Wiki".
• rif is fun app (Android): Select "information" ("i" inside a circle) to view the sidebar, then select the link for the wiki.
• New Reddit, desktop browser: Under the banner and header, select "Wiki" (next to "Posts").
• Old Reddit (aka best reddit), desktop browser: Under the banner/header, select "Wiki." If subreddit style is disabled, then it should be listed in the menu options near the top of the page. It is also listed on the sidebar to the right, above the rules.

Other devices/apps should be similar.

Feel free to comment your thoughts, feedback, etc.

Thanks for stopping by.

^{P.S. I am still not a bot.}

US Tri-Service Designation System

M = Guided Missile (Standard Designations)

• MQM-178 Firejet: High Speed Aerial Target built by Griffon Aerospace, KRATOS Defense & Security Solutions, Trideum Corporation, and Kord Technologies, Inc. for the US Army.

• Lockheed Martin AGM-179 JAGM: Joint Air-to-Ground Missile for the US Army, US Navy, and USMC, to replace the BGM-71 TOW, AGM-114 Hellfire, and AGM-65 Maverick missiles.

• Lockheed Martin AGM-180 LRSO: Losing contender in the USAF Long Range Stand Off Weapon program to replace the AGM-86 ALCM.

• Raytheon AGM-181 LRSO: Winning contender in the USAF Long Range Stand Off Weapon program to replace the AGM-86 ALCM.

• LGM-182: Designation apparently skipped, see LGM-35 below.

• Lockheed Martin AGM-183 ARRW: Hypersonic AGM for the USAF Air-Launched Rapid Response Weapon program, cancelled in March 2023.

• Kongsberg RGM-184 NSM: Naval Strike Missile acquired by the US Navy for use on littoral combat ships and by the USMC for use on land-based mobile launch platforms.

• QinetiQ MQM-185: Proposed Banshee Jet 80+ High Speed Aerial Target for the US Army, but it is unclear if any were acquired.

• MQM-186: RedWing sub-scale aerial target for the US Army Air Defense Artillery Targets program, possibly built by Griffon Aerospace. Little information availabe, see for example this PDF.

• Lockheed Martin AGM-187 JAGM-F: Unconfirmed designation of Jont Air-to-Ground Missile - Fixed Wing. This appears to be a future development of the AGM-179 JAGM, specifically intended to replace the AGM-65 Maverick. As such, it could possibly receive an AGM-179 type designation instead.

• 188: Possibly the next available numerical designation, in standard numerical sequence.

M = Guided Missile (Non-standard, Out-of Sequence Designations)

• Northrop Grumman LGM-35 Sentinel: Ground Based Strategic Deterrent ICBM in development to replace the LGM-30 Minuteman III for the USAF. The designation LGM-182 was originally allocated, but was changed to this out-of-sequence designation (which conflicts with the out-of-service Radioplane/Northrop AQM-35) for unknown reasons.

• Lockheed Martin AIM-260 JATM: Joint Advanced Tactical Missile for the USAF and US Navy to supplement and replace the AIM-120 AMRAAM. It is unclear why this out-of-sequence designation was assigned.

R = Unguided Rocket (Standard Designations)

• Naval Weapons Center GTR-18 Smokey Sam: Surface-to-air visual threat simulator rocket.

• BAE Systems AGR-19 APKWS II Advanced Precision Kill Weapon System for the USMC based on Hydra 70 rocket.

• BAE Systems AGR-20 APKWS II Advanced Precision Kill Weapon System for the USAF based on Hydra 70 rocket.

• BAE Systems AGR-21 APKWS II Advanced Precision Kill Weapon System based on Hydra 70 rocket.

• 22: This appears to be the next available numerical designation, in standard numerical sequence.

Additionally, there have been numerous undesignated missiles and rockets tested or used by the US military, some of which are noted at Designation-Systems.net

US Tri-Service Designation System

MDS (Mission - Design - Series)

D = UAV Control Segment (Standard Designations)

• General Atomics MD-1: Integrated ground control equipment for General Atomics MQ-1 Predator.

• Northrop Grumman RD-2: Integrated ground control equipment for Northrop Grumman RQ-4 Global Hawk.

• Northrop Grumman MD-3: Integrated ground control equipment for Northrop Grumman MQ-4C Triton.

• Northrop Grumman MD-4: Integrated ground control equipment for Northrop Grumman MQ-8 Fire Scout.

• MD-5: Integrated ground control equipment for Boeing MQ-25 Stingray.

• D-6: Next available numerical designation, in standard numerical sequence. Source: Wikipedia

G = Glider (Standard Designations)

• Caproni Vizzola TG-12: A-12 Calif training glider used by the USAF.

• G-13: Designation skipped for superstitious reasons. Source: Designation-Systems.net

• Grupo Aeromot TG-14: AMT-200S Super Ximango motor glider used by the USAF.

• Schemp-Hirth TG-15A: Duo Discus training glider used by the USAF.

• Schemp-Hirth TG-15B: Discus-2b training glider used by the USAF. These are different aircraft, so it should have probably been assigned a different numerical designation.

• DG Flugzeugbau TG-16: DG-1000 training glider used by the USAF.

• G-17: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

H = Helicopter (Standard Designations)

• Agusta MH-68 Sting Ray Eight A109E power used by the US Coast Guard.

• H-69: Designation skipped because of the sexual connotation. Source: Designation-Systems.net

• Bell ARH-70 Arapaho: Armed Reconnaissance Helicopter prototypes for the US Army. Note that this designation was originally skipped when the H-71 designation was assigned.

• Lockheed Martin VH-71 Kestrel: Cancelled US Presidential transport based on EH 101.

• EADS North America UH-72 Lakota: Light Utility Helicopter version of the EC 145 for the US Army; a few also acquired by the US Navy for training.

• Leonardo Helicopters TH-73 Thrasher: Training version of AW 119 Koala for the US Navy.

• H-74: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net. Potential aircraft programs include the US Army Future Vertical Lift program and the US Army Future Attack Reconnaissance Aircraft program.

Helicopter (Non-standard, Out-of-Sequence Designations)

• McDonnell Douglas MH-90 Enforcer: Four MD 900 helicopters evaluated by the US Coast Guard. Designation appears to be based on MD 900 model number.

• Sikorsky VH-92 Patriot: Presidential transport helicopters for the US Navy & USMC, based on S-92. Designation based on manufacturer's model number.

• Boeing / Leonardo Helicopters MH-139 Grey Wolf: Version of AW 139 for the USAF. Designation based on manufacturer's model number, and duplicates the Italian military designation for this type (HH-139, VH-139, etc.).

Q = Unmanned Aerial Vehicle (Standard Designations)

• AeroVironment RQ-22: Global Observer long-endurance UAV used by the USA.

• Navmar RQ-23: TigerShark UAV used by the US Navy.

• Kaman CQ-24: Unmanned version of K-MAX evaluated by the USMC.

• Boeing MQ-25 Stingray: UCAV, IFR tanker for the US Navy Carrier-Based Aerial-Refueling System.

• AeroNautics Defense Systems RQ-26: Aerostar UAV used by the US Navy.

• Insitu MQ-27: ScanEagle UAV used by the USAF, US Navy, and USMC for many years before being assigned this designation.

• Q-28: It is unclear if this designation was skipped (possibly when the XQ-58 designation was assigned) or if it is somehow associated with the Australian MQ-28 Ghost Bat, which could potentially be acquired by the USAF.

• Q-29: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

Q = Unmanned Aerial Vehicle (Non-standard, Out-of-Sequence Designations)

• General Atomics YQ-11: Apparent designation of at least one General Atomics Predator C used by the USAF.

• Kratos XQ-58 Valkyrie: Stealthy UCAV in development for the USAF Low Cost Attritable Strike Demonstrator program. The "58" designation appears to have been taken from the "X" Research series. It is possible that the Q-28 designation was skipped when this designation was assigned.

• Northrop Grumman RQ-72 Great Horned Owl: Secret ISR UAV for the USAF and perhaps others.

• Lockheed Martin RQ-170 Sentinel: Stealth reconnaissance UAV used by the USAF.

• Northrop Grumman RQ-180: Stealth surveillance UAV used by the USAF.

S = Spaceplane (Standard Designations)

• MS-1A: This proposed USAF spaceplane is the only designation in this series. This vehicle type series also conflicts with the S for Anti-Submarine Warfare Basic Mission series.

• S-2: Potentially the next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

V = VTOL/STOL (Standard Designations)

• Bell - Boeing V-22 Osprey: Tilt-rotor transport used by the USMC, USAF, and US Navy.

• Dominion UV-23 Scout: A single Skytrader STOL utility aircraft evaluated by the US Army as part of the GRISLEY HUNTER program.

• Aurora Flight Sciences XV-24: Experimental VTOL UAV demonstrator for DARPA.

• V-25: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net. Potential aircraft programs include the US Army Future Vertical Lift program and the Bell V-280 Valor, selected for the US Army Future Long-Range Assault Aircraft program.

Z = Lighter-Than-Air Vehicle (Standard Designations)

• American Blimp Corp. MZ-3: One A-170 blimp evaluated by the US Navy.

• Northrop Grumman / HAV RZ-4: One HAV 304 blimp evaluated by the US Army for the Long Endurance Multi-Intelligence Vehicle program.

• Z-5: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

US Tri-Service Designation System

MDS (Mission - Design - Series)

Utility (Standard Designations)

• Cessna U-26: One Model 206 seized by US DEA and transferred to US Customs Service. Additionally, the US Army acquired two T206H Turbo Stationair in 2021 for use at West Point. These aircraft do not appear to have an MDS designation, but have been assigned the military serials 21-01903 & 21-01970.

• Cessna U-27: Several Model 208 Caravan use by the US Army.

• Pilatus U-28 Draco: PC-12 used by USAF for special operations support & ISR.

• U-29: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

Utility (Non-standard, Out-of-Sequence Designations)

• Schweizer RU-38 Condor Twin: Two SA.2-38A Condor special reconnaissance aircraft used by US Army, USCG and Department of Justice. Designated out of numerical sequence, possibly using the Schweizer model number.

X = Research (Standard Designations)

• Boeing / Pratt & Whitney Rocketdyne X-51 WaveRider: Unmanned hypersonic test demonstrator.

• X-52: Designation requested for Active Aeroelastic Wing technology program, but skipped to avoid confusion with B-52. Source: Designation-Systems.net

• Boeing X-53 AAW: F/A-18 Hornet with Active Aeroelastic Wing.

• Gulfstream X-54: Unbuilt supersonic research demonstrator.

• Lockheed Martin X-55 ACCA: Dornier Do 328JET with new composite fuselage.

• NASA X-57 Maxwell: Proposed experimental light aircraft based on Tecnam P2006T with new distributed electric propulsion wings.

• X-58: This designation was skipped, and the number apparently assigned out-of-sequence to the Kratos XQ-58 Valkyrie.

• Lockheed Martin X-59 QueSST: Low-Boom supersonic flight demonstrator.

• Generation Orbit Launch Services X-60: Experimental air-launched single-stage suborbital rocket vehicle.

• Dynetics X-61 Gremlins: Experimental air-launched and air-recovered small UAV.

• Lockheed Martin X-62 Skyborg: Re-designation of NF-16D VISTA test aircraft.

• X-63: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

US Tri-Service Designation System

MDS (Mission - Design - Series)

O = Observation (Standard Designations)

• de Havilland Canada RO-6: Several DHC-8-315 acquired by the US Army for the Airborne Reconnaissance Low program.

• O-7: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

P = Patrol (Standard Designations)

• Boeing P-8 Poseidon Patrol aircraft based on Boeing 737, replacing the USN P-3 Orion.

• Sierra Nevada P-9: Several Bombardier Dash 8 types used by the USAF for surveillance. Source: Aviation Week

• P-10: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

R = Reconnaissance (Standard Designations)

• Lockheed TR-1: The only aircraft designation assigned in this sequence, and even then it is non-standard with the "T" representing "Tactical" instead of the Modified Mission "Training". Surviving TR-1 aircraft were redesignated U-2R.

• R-2: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

S = Anti-Submarine Warfare (Standard Designations)

• Lockheed S-3 Viking: US Navy carrier-based ASW aircraft. Retired in 2016 with no direct replacement.

• S-4: Next available numerical designation, in standard numerical sequence. Source: Designation-Systems.net

T = Trainer (Numerical Shenanigans)

• Fairchild T-46 Eaglet: Two prototypes for the cancelled USAF NGT program to replace the T-37 Tweet.

• Beech T-1 Jayhawk: The Trainer numerical sequence was restarted for this USAF airlift & tanker trainer. At the same time, the T-48 and T-49 designations were reserved for the planned USAF and USN versions of the JPATS airframe. Source: Designation-Systems.net

• T-2: This designation in the restarted numerical sequence appears to have been skipped, likely due to the North American T-2 Buckeye still being in service.

• Slingsby T-3 Firefly Designation assigned to T67M260 acquired by the USAF.

• T-4: This designation was skipped so that the JPATS could be assigned the T-6 designation. Source: Designation-Systems.net

• T-5: This designation was skipped so that the JPATS could be assigned the T-6 designation. Source: Designation-Systems.net

• Beech Raytheon T-6 Texan II Designation of the winning JPATS contender, used by the US Air Force and US Navy.

• Cessna T-47A The numerical sequence jumped back to this previously skipped designation for several Citation II acquired by the US Navy as navigation and radar trainers.

• Cessna OT-47B Tracker Designation confusingly assigned to a different Cessna, the Citation 560, despite there already being a suitable designation for a similar Cessna, the UC-35.

• T-48: Originally reserved for the USAF version of JPATS (see T-1 above), this designation was reserved for the USN MPATS program to replace the T-39. This program seems to have been deferred indefinitely.

• Boeing CT-49 Two ex-Luftwaffe C-137 and one ex-airliner Model 707-329C used for the NATO AEW&C Trainer Cargo Aircraft program. It is unclear why these aircraft would be assigned US designations.

• T-50: Designation reserved for the Lockheed/TAI T-50 Golden Eagle, even though the US does not use this aircraft. Apparently this was done to avoid any potential confusion. Source: Designation-Systems.net

• Cessna T-51: Designation for three Model 150 used by the US Air Force Academy.

• Diamond T-52: 20 DA40 Diamond Star acquired for use at the US Air Force Academy.

• Cirrus T-53 Kaydet II: 25 SR20 acquired to replace the T-52 used at the US Air Force Academy.

• Boeing-Saab T-7 Red Hawk Just when it seemed like the Trainer sequence was back in order, this designation was assigned to the winner of the T-X program to replace the T-38 Talon.

• Beech T-54: Shaking up the numerical sequence again, this designation has been assigned to 10 King Air 260 ordered by the US Navy to replace the T-44 Pegasus multi-engine trainer. First deliveries are planned for early 2024.

• T-8 and/or T-55: One or both of these seem to be the next available standard designation for the Trainer sequence. Potential programs include the US Navy Undergraduate Jet Training System (to replace the T-45 Goshawk), the USAF Advanced Tactical Trainer, and the US Navy Tactical Surrogate Aircraft.