View source for McDonnell Douglas KC-10 Extender

{{Short description|US aerial refueling tanker aircraft}}
{{Use dmy dates|date=August 2019}}
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{{Infobox aircraft
| name = KC-10 Extender
| image = KC-10 Extender (2151957820).jpg
| caption = A [[United States Air Force]] KC-10 Extender refueling an [[F-16 Fighting Falcon]]
| alt = Large three-engined aircraft refueling a jet fighter while two more of the latter fly in the distance.
| type = [[Aerial refueling|Tanker]]/[[Military transport aircraft|transport]]
| manufacturer = [[McDonnell Douglas]]
| national_origin = United States
| designer = 
| first_flight = {{Start date and age|1980|07|12|df=yes}}
| introduction = {{Start date and age|1981|03|01|df=yes}}
| retired = 2021 (RNLAF)<br>2024 (USAF)
| status = In limited service
| primary_user = [[United States Air Force]] (historical)
| more_users = [[Omega Aerial Refueling Services]] <br>[[Royal Netherlands Air Force]] (historical)
| produced = 1979–1987 (KC-10)
| number_built = KC-10: 60 <br>KDC-10: 2<ref name="dutch-kdc10-eval"/>
| developed_from = [[McDonnell Douglas DC-10]]
| variants = 
}}

The '''McDonnell Douglas KC-10 Extender''' is an American tanker and [[cargo aircraft]] that was operated by the [[United States Air Force]] (USAF) from 1981 to 2024. A military version of the three-engine [[McDonnell Douglas DC-10|DC-10]] airliner, the KC-10 was developed from the '''Advanced Tanker Cargo Aircraft Program'''.{{#tag:ref|The [[Handley Page Jetstream]] had been initially ordered as the C-10, but was soon canceled. This allowed the tanker version of the DC-10 to be designated KC-10A.|group="N"}} It incorporates military-specific equipment for its primary roles of [[aerial refueling]] and transport. It was developed to supplement the [[KC-135 Stratotanker]] following experiences in [[Southeast Asia]] and the [[Middle East]]. The KC-10 was the second McDonnell Douglas transport aircraft to be selected by the Air Force following the [[McDonnell Douglas C-9|C-9]]. A total of 60 KC-10s were produced for the USAF. The [[Royal Netherlands Air Force]] operated two similar tankers from 1995 to 2021 designated ''KDC-10'' that were converted from used civilian DC-10, instead of purpose built aircraft.<ref name="Retirement">{{cite web |title=Final KC-10 Extender Tanker Flies Into Retirement |date=26 September 2024 |url=https://www.twz.com/air/final-kc-10-extender-tanker-sent-into-retirement |publisher=The War Zone |access-date=26 September 2024}}</ref>

The KC-10 played a key role in the mobilization of US military assets, taking part in overseas operations far from home. These aircraft performed airlift and aerial refueling during the [[Bombing of Libya (1986)|1986 bombing of Libya]] (Operation Eldorado Canyon), the 1990–91 [[Gulf War]] with Iraq (Operations Desert Shield and Desert Storm), the [[NATO bombing of Yugoslavia]] (Operation Allied Force), [[War in Afghanistan (2001–present)|War in Afghanistan]] ([[Operation Enduring Freedom]]), and [[Iraq War]] (Operations Iraqi Freedom and New Dawn).

==Design and development==
===Advanced Tanker Cargo Aircraft Program===
[[File:AN air-to-air left side view of a KC-10 Extender aircraft refueling a C-5 Galaxy aircraft - DPLA - ddb9e73e4eb4f688c466e70c9a31f1da.jpeg|thumb|right|An early KC-10 Extender aircraft refuels a C-5 Galaxy in 1980. Both aircraft are wearing liveries typical of that era.]]

During the [[Vietnam War]], doubts began to form regarding the [[Boeing KC-135 Stratotanker]] fleet's ability to meet the needs of the United States' global commitments. The [[aerial refueling]] fleet was deployed to Southeast Asia to support tactical aircraft and strategic bombers, while maintaining the U.S.-based support of the nuclear-bomber fleet. Consequently, the Air Force sought an aerial tanker with greater capabilities than the KC-135. In 1972, two [[McDonnell Douglas DC-10|DC-10s]] were flown in trials at [[Edwards Air Force Base]], simulating air refuelings to check for possible wake issues. Boeing performed similar tests with a 747.<ref name=Waddington>Waddington 2000, pp. 116–120.</ref>

During the 1973 [[Yom Kippur War]], the Air Force commenced [[Operation Nickel Grass]] to supply Israel with weapons and supplies. The operation demonstrated the necessity for adequate air-refueling capabilities; denied landing rights in Europe, [[Lockheed C-5 Galaxy|C-5 Galaxy]] transports were forced to carry a fraction of their maximum payload on direct flights from the continental United States to [[Israel]].<ref>Endres 1998, p.&nbsp;65.</ref><ref name=Steffen_p103>Steffen 1998, p.&nbsp;103.</ref> To address this shortfall in mobility, in 1975, under the ''Advanced Tanker Cargo Aircraft Program'', four aircraft were evaluated—the [[Boeing 747]], [[Lockheed C-5 Galaxy|Lockheed C-5]], [[Lockheed L-1011]] and McDonnell Douglas DC-10.<ref name=Frawley_mil>Frawley 2002, p.&nbsp;119.</ref> In December 1977, the DC-10 was chosen, primarily for its ability to operate from shorter runways.<ref name=Steffen_p103 /> Initially, 12 aircraft were ordered, but this was later increased to 60.<ref name=Steffen_p103 />

===KC-10 Extender===
The KC-10 Extender first flew in July 1980. In October 1980 the first aerial refuel sortie was performed.<ref name=Steffen_p104>Steffen 1998, p.&nbsp;104.</ref><ref name=GS_KC10_bg>{{cite web |title=KC-10A Extender: Background |url=http://www.globalsecurity.org/military/systems/aircraft/kc-10-background.htm |work=Globalsecurity.org |access-date=27 August 2011}}</ref> The KC-10 is largely based on the design of the civilian DC-10-30CF, a convertible cargo/passenger transport variant with an extended range compared to the baseline DC-10-10. For the KC-10, unnecessary features including most windows and lower cargo doors were removed, an improved cargo-handling system was added and the [[avionics]] were tailored to the military's needs.<ref>Eden 2004, p&nbsp;286.</ref><ref name="GS_KC10_char">{{cite web |title=KC-10A Extender: Characteristics |url=http://www.globalsecurity.org/military/systems/aircraft/kc-10-characteristics.htm |access-date=27 August 2011 |work=Globalsecurity.org}}</ref> The KC-10 retained an 88% [[commonality]] with its civilian counterparts, giving it greater access to the worldwide commercial support system.<ref name=Steffen_p103 />

Early aircraft featured a distinctive light gray and white paint scheme typical of that era. A gray-green camouflage scheme was used on later tankers. The paint scheme was switched to the Air Force standard gray color by the late 1990s.<ref name="steffen_p103-7">Steffen 1998, pp.&nbsp;103–107.</ref>

[[File:A KC-10A Extender aircraft refueling boom operator of the 9th Air Refueling Squadron refuels an F-4 Phantom II aircraft during Theater Force Employment Exercise IV DF-ST-86-04188.jpg|thumb|right|The KC-10's refueling boom operator is seated rather than prone|alt=The KC-10's refueling boom operator cockpit is seated rather than prone.]]
The most notable changes were the addition of the McDonnell Douglas Advanced Aerial Refueling Boom and additional fuel tanks located in the baggage compartments below the main deck. The extra tanks increase the KC-10's fuel capacity to {{convert|356,000|lb|kg}}, nearly double the KC-135's capacity.<ref name=Steffen_p104 /> The KC-10 has both a centerline [[Flying boom|refueling boom]]—unique in that it sports a control surface system at its aft end that differs from the [[V-tail]] design used on previous tankers—and a [[Probe and drogue|drogue-and-hose]] system on the starboard side of the rear fuselage. The KC-10 boom operator cockpit is seated in the rear of the aircraft with a wide window for monitoring refueling rather than [[Prone pilot|prone]] as in the KC-135. The operator controls refueling operations through a digital [[Aircraft flight control system#Fly-by-wire control systems|fly-by wire system]].<ref name=steffen_p103-7 /><ref>Eden 2004, p&nbsp;287.</ref> The refueling boom can deliver fuel to a receiver at the maximum rate of {{convert|1,100|USgal|liter|abbr=off|sp=us}} per minute, while the centerline drogue system has a maximum fuel offload rate of {{convert|470|USgal|liter|abbr=off|sp=us}} per minute.<ref name="af.mil">{{cite web |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104520/kc-10-extender/ | title=KC-10 Extender }}</ref>

[[File:US Navy 021107-N-2794R-002 KC-10 'Extender' refuels a F-A-18C 'Hornet'.jpg|thumb|right|The KC-10's mixed refueling system of hose-and-drogue and flying-boom allows it to refuel the aircraft of the U.S. Air Force, U.S. Navy, U.S. Marine Corps and allied forces.<ref name=Steffen_p104 />|alt=A jet aircraft refuels from a gray three-engine tanker via a long boom located under the tanker's aft fuselage.]]
Unlike the KC-135, the KC-10's hose-and-drogue system allows refueling of [[United States Navy|Navy]], [[United States Marine Corps|Marine Corps]], and most allied aircraft, all in one mission.<ref name=Steffen_p104 /> The final twenty KC-10s produced included wing-mounted hose-and-drogue pods for added refueling locations.<ref name="Waddington" /> The KC-10 can carry a complement of 75 personnel with {{convert|146,000|lb|kg}} of cargo, or {{convert|170,000|lb|kg}} in an all-cargo configuration.<ref name=Steffen_p104 />  With that, it can transport those weights for an unrefueled range of {{convert|4,400|mi|km}}.<ref name="af.mil"/> The KC-10 has a large door located just behind the flight deck for loading and unloading cargo. [[Ground support equipment#Container loader|Handling equipment]] is required to raise and lower loads to the cargo opening. The aircraft can still perform aerial refueling while carrying cargo.<ref name=USAF_factht>{{cite web |url=https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104520/kc-10-extender/ |title=Factsheets: KC-10 Extender |publisher=US Air Force |date= May 2014 |access-date=30 November 2013}}</ref>

===Further developments===
A need for new transport aircraft for the [[Royal Netherlands Air Force]] (''Koninklijke Luchtmacht'') was first identified in 1984.<ref name="dutch-kdc10-eval"/> The 1991 [[Gulf War]] highlighted the deficiencies in mobility of European forces.<ref>Steffen 1997, p.&nbsp;107.</ref>  In 1991, four categories of transport requirements were established. Category A required a large cargo aircraft with a range of at least 4,500&nbsp;km and the capability to refuel F-16s. In 1992, two DC-10-30CFs were acquired from [[Martinair]] in a buy/[[leaseback]] contract. When one of the two aircraft was lost in the [[Martinair Flight 495]] crash, a third aircraft was bought from Martinair.<ref name="dutch-kdc10-eval"/>

The conversion was handled via the United States [[foreign military sales]] program, which contracted McDonnell Douglas. Costs for the conversion were initially estimated at $89.5&nbsp;million (FY 1994). The aircraft were to be equipped with both a boom and a probe and drogue system. Because McDonnell Douglas did not have any experience with the requested Remote Aerial Refueling Operator (RARO) system, and because the third aircraft differed from the original two, the program could not be completed at budget. By omitting the probe and drogue system and a fixed partition wall between the cargo and passenger, the cost could be limited at $96&nbsp;million.<ref name="dutch-kdc10-eval"/>

To make up for the cost increase McDonnell Douglas hired Dutch companies to do part of the work. The conversion of the aircraft was performed by [[KLM]] and was done from October 1994 to September 1995 for the first aircraft and from February to December 1995 for the second. This was much longer than planned, mostly because McDonnell Douglas delivered the parts late. This would have again increased the cost, but in the contract for the [[AH-64 Apache]]s which the Royal Netherlands Air Force also bought from McDonnell Douglas, the price was agreed to be kept at $96&nbsp;million.<ref name="dutch-kdc10-eval">{{cite web |url=https://zoek.officielebekendmakingen.nl/kst-26665-1.html |title=Evaluatie project KDC-10 |language=nl |work=Ministerie van Defensie |date=1 July 1999 |access-date=5 January 2014}}</ref>

In 2010, the USAF awarded a contract to Boeing to upgrade the fleet of 59 aircraft with new [[Communication, navigation and surveillance]] and air traffic management (CNS/ATM) system. This was to allow the aircraft to fly in civil airspace as new [[International Civil Aviation Organization|ICAO]] and [[Federal Aviation Administration|FAA]] standards took effect in 2015.<ref name="fg_kc10"/>  Rockwell Collins was awarded a contract in 2011 for avionics and systems integration for the cockpit modernization program.<ref>{{cite web |url= http://www.defenseindustrydaily.com/Boeing-Wins-CNS-ATM-Upgrade-Contract-for-USAFs-KC-10-Tankers-06448/ |title=Boeing Wins CNS-ATM Upgrade Contract for USAF's KC-10 Tankers |website=Defenseindustrydaily.com |date=2014-08-21 |access-date=2017-03-16}}</ref><ref>{{cite web |url= http://www.rockwellcollins.com/sitecore/content/Data/News/2011_Cal_Yr/GS/FY11GSNR27-KC10_cockpit_upgrade.aspx |archive-url= https://web.archive.org/web/20110909051542/http://www.rockwellcollins.com/sitecore/content/Data/News/2011_Cal_Yr/GS/FY11GSNR27-KC10_cockpit_upgrade.aspx |url-status=dead |archive-date=2011-09-09 |title=Rockwell Collins awarded contract for KC-10 CNS/ATM cockpit upgrade program |access-date=2019-01-16}}</ref>

==Operational history==
===United States===
The first KC-10 was delivered to the Air Force's [[Strategic Air Command]] (SAC) in March 1981 at [[Barksdale AFB]]. In 1982 a newly renamed [[22d Air Refueling Wing]], formerly the 22d Bombardment Wing, was re-equipped with KC-10A Extenders and became the second Air Force unit to operate the new tankers.{{citation needed|date=February 2019}} The 60th and final KC-10 was delivered on 29 November 1988.<ref>Steffen 1998, pp.&nbsp;104, 107.</ref> The KC-10s served with SAC until 1992, when they were reassigned to the newly established [[Air Mobility Command]]. In the aerial refueling role, the KC-10s have been operated largely in the strategic refueling of large number of tactical aircraft on ferry flights and the refueling of other strategic transport aircraft. Conversely, the KC-135 fleet has operated largely in the in-theater tactical role. There are 59 KC-10 Extenders in service with the USAF as of 2010.<ref name=USAF_factht/><ref name="fg_kc10">{{cite web |last=Trimble |first=Stephen |url=http://www.flightglobal.com/articles/2010/06/24/343673/boeing-outlines-c-130h-and-kc-10-cockpit-upgrades.html |title=Boeing outlines C-130H and KC-10 cockpit upgrades |work=[[Flightglobal.com]] |date= 24 June 2010 |access-date=19 September 2010}}</ref> The USAF's KC-10s are stationed primarily at [[Travis Air Force Base|Travis AFB]], California, and [[McGuire Air Force Base|McGuire AFB]], now part of Joint Base McGuire-Dix-Lakehurst, in New Jersey.

[[File:USAF F-14D and F-18C's prepare to refuel.jpg|thumb|right|A US Navy [[F-14D]] and two [[F/A-18C]]s prepare to refuel from a KC-10 in 2005 over the [[Persian Gulf]].]]
When faced with refusals of basing and overflight rights from continental European countries during [[Operation El Dorado Canyon]], the U.S. was forced to use the UK-based [[General Dynamics F-111 Aardvark|F-111s]] in the 1986 air-strikes against [[Libya]]. The KC-10s and KC-135s allowed 29 F-111s, along with other Air Force and Navy aircraft, to reach their targets.<ref>{{cite web |title=Operation El Dorado Canyon |url=http://www.globalsecurity.org/military/ops/el_dorado_canyon.htm |work=Globalsecurity.org |access-date=27 August 2011}}</ref> The KC-10 again played a key role during [[Operation Desert Shield|Operations Desert Shield]] and [[Operation Desert Storm|Desert Storm]] in 1991. KC-10s facilitated the deployment of tactical, strategic, and transport aircraft to [[Saudi Arabia]]. In the early stages of Operation Desert Shield, aerial refueling was key to the rapid airlift of materiel and forces. In addition to refueling airlift aircraft, the KC-10, along with the smaller KC-135, moved thousands of tons of cargo and thousands of troops in support of the massive buildup. The KC-10 and the KC-135 conducted about 51,700 separate refueling operations and delivered 125 million gallons (475 million liters) of fuel without missing a single scheduled rendezvous.<ref name=USAF_factht/>

[[File:McDonnell-Douglas KC-10 Extender prepares to be refuelled by another KC-10, Exercise Talisman Saber 2017.jpg|thumb|right|A KC-10 Extender of [[Travis AFB]] approaching a second KC-10 for refuelling over the [[Pacific Ocean]], 2017]]
Since then, the KC-10 had participated in other smaller conflicts. In March 1999, NATO launched [[Operation Allied Force]] against the government of [[Yugoslavia]]. The mobility portion of the operation began in February and was heavily dependent on tankers. By early May 1999, some 150 KC-10s and KC-135s deployed to Europe where they refueled bombers, fighters and support aircraft engaged in the conflict. The KC-10 flew 409 missions throughout the entire Allied Force campaign and continued support operations in [[Kosovo]].<ref name=USAF_factht/> Since 11 September 2001, KC-10s had flown more than 350 missions guarding U.S. skies as a part of [[Operation Noble Eagle]]. During [[Operation Enduring Freedom|Operations Enduring Freedom]] and [[Operation Iraqi Freedom|Iraqi Freedom]], KC-10s flew more than 1,390 missions delivering critical air refueling support to numerous joint and Coalition receiver aircraft.<ref name=USAF_factht/> As of 2004, KC-10s were expected to serve until 2043.<ref>Veronico and Dunn 2004, p.&nbsp;58.</ref>

The Air Force considered retiring its fleet of KC-10 tankers in response to sequestration budget cuts as part of the service's FY 2015 budget. A "vertical chop" to divest all KC-10s was suggested because there are fewer KC-10s than KC-135s, having three different tanker models in service after the introduction of the [[KC-46]] would be costly, and a "horizontal cut" across the refueling fleets would achieve small efficiencies.<ref>[http://www.dodbuzz.com/2013/09/17/air-force-may-scrap-kc-10-tanker-fleet-general/ Air Force May Scrap KC-10 Tanker Fleet] – DoDBuzz.com, 17 September 2013</ref> Some believed retiring the KC-10 would not benefit the Air Force, given that it is equipped with both boom and hose-and-drogue refueling systems and the fleet's relatively young age.<ref>{{cite web |url=http://www.defensenews.com/article/20130915/DEFREG02/309150004/ |archive-url=https://archive.today/20131030185420/http://www.defensenews.com/article/20130915/DEFREG02/309150004/ |url-status=dead |archive-date=30 October 2013 |title=USAF Weighs Scrapping KC-10, A-10 Fleets |last1=WEISGERBER |first1=MARCUS |last2=MEHTA |first2=AARON |date=15 September 2013 |website=www.defensenews.com |publisher=Gannett Government Media Corporation |access-date=30 October 2013}}</ref>

[[File:240926-F-OY799-1632.jpg|thumb|The last U.S. Air Force KC-10 takes off from Travis Air Force Base, California, 26 Sept. 2024.]]
At first, officials claimed that the initial focus on retiring the KC-10 in September 2013 was a "trial balloon" to call attention to Air Force operating cost issues. As of early 2013, the KC-10 had a per hour flying cost of $21,170 and a mission capable rate of 87 percent.<ref>[http://www.defensemedianetwork.com/stories/air-force-may-dump-all-a-10s/ Air Force May Scrap Entire A-10 Fleet] – Defensemedianetwork.com, 17 October 2013</ref> A FY 2015 budget plan did not include cuts to the KC-10.<ref>[http://www.flightglobal.com/news/articles/how-hagel-spending-plan-will-transform-us-military-396320/ How Hagel spending plan will transform US military] – Flightglobal.com, 26 February 2014</ref>  In July 2020, the first US KC-10 to be retired, tail number 86-0036, was transferred to the [[309th Aerospace Maintenance and Regeneration Group]] (AMARG) for storage at Davis-Monthan Air Force Base, Arizona.<ref>{{cite web|url=https://www.airforcetimes.com/news/your-air-force/2020/07/16/first-kc-10-heads-to-boneyard-as-pegasus-comes-in/|title=First KC-10 heads to Boneyard as Pegasus comes into the fleet|date=16 July 2020}}</ref>

In July 2021, the 2d ARS was the first KC-10 squadron to start conversion to the KC-46.<ref>{{cite web |url=https://www.airandspaceforces.com/mcguire-squadron-says-goodbye-to-kc-10-prepares-for-kc-46/ |title=McGuire Squadron Says Goodbye to KC-10, Prepares for KC-46 |date=2 July 2021 }}</ref> In August 2021, the KC-10 took part in the largest non-combatant evacuation in support of Operation Allies refuge and contributing to the safe evacuation of more than 124,000 Afghan refugees.<ref>{{cite web |url=https://www.travis.af.mil/News/Article/3131472/operation-allies-refuge-one-year-later/ |title=Operation Allies Refuge: One year later |date=17 August 2022}}</ref>

In January 2023, the USAF announced that all KC-10s are to be retired by 30 September 2024.<ref>{{cite web |url=https://www.dvidshub.net/news/437483/end-10 |title=End of the 10 |publisher=349th Air Mobility Wing Public Affairs |author=Rossi Pedroza-Bertrand |date=30 January 2023 |access-date=13 April 2023}}</ref> The KC-10 flew its last combat sortie for the USAF on 5 October 2023.<ref>{{Cite web |last=Newdick |first=Thomas |date=2023-10-05 |title=KC-10 Extender Has Flown Its Last Combat Mission |url=https://www.thedrive.com/the-war-zone/kc-10-extender-has-flown-its-last-combat-mission |access-date=2023-10-06 |website=The Drive |language=en}}</ref> On 26 September 2024, the KC-10 flew its final sortie on tail number 79-1948 bound for the 309th Aerospace Maintenance and Regeneration Group (AMARG) at Davis-Monthan Air Force Base, Arizona.<ref>{{Cite news |last=60th Air Mobility Wing Public Affairs |date=27 September 2024 |title=Travis AFB bids farewell to last KC-10  |url=https://www.af.mil/News/Article-Display/Article/3919933/travis-afb-bids-farewell-to-last-kc-10/ |access-date=27 September 2024 |work=U.S. Air Force News}}</ref>

===Netherlands===
The two Dutch KDC-10s were used for both refueling and transport.<ref>Steffen 1997, pp.&nbsp;106–107.</ref> They were stationed on [[Eindhoven Airport]] as part of the 334th Transport Squadron. Of the 5,500 hours flown in the first three years of use, the aircraft were used in their tanker role for 50% of the time. Besides being used by the air force and NATO allies, the KDC-10s were also used to support [[peacekeeping]] and [[humanitarian aid]] operations. Of the first three years, 32% of the flight hours were used for peacekeeping and humanitarian aid.<ref name="dutch-kdc10-eval"/>

[[File:McDonnell Douglas KDC-10-30CF der RNLAF.jpg|thumb|left|The second [[Royal Netherlands Air Force]] KDC-10 with landing gear down]]
In this function, the aircraft was deployed to Kosovo to evacuate refugees, to the [[Caribbean]] and [[Central America]] to provide humanitarian aid after the hurricanes [[Hurricane Luis|Luis]], [[Hurricane Georges|Georges]] and [[Hurricane Mitch|Mitch]] and to various countries in Africa and Asia to provide [[development aid]]. In 1998, the aircraft were used to evacuate Dutch citizens from Indonesia during the [[Fall of Suharto]]. Dutch KDC-10s operated out of [[Transit Center at Manas|Manas AFB]] in support of allied forces during Operation Enduring Freedom and in support of Allied Air Force over Iraq and Syria.

A third cargo-only DC-10, registered T-255 was acquired and served for three years before being withdrawn from service in April 2014 due to Dutch defense cuts and flown to [[Newquay Airport]] for scrapping.<ref>{{cite web|url=https://www.flightglobal.com/news/articles/dutch-air-force-scraps-dc-10-transport-398498/|access-date=23 June 2019|title=Dutch air force scraps DC-10 transport|website=flightglobal.com}}</ref> The KDC-10s in Dutch service were replaced with the [[Airbus A330 MRTT]].<ref name="key.aero">{{cite web|url=https://www.key.aero/article/rnlafs-final-kdc-10-tanker-leaves-netherlands|title=RNLAF's final KDC-10 tanker leaves the Netherlands|website=key.aero|date=25 October 2021|access-date=21 November 2021}}</ref> The first aircraft, registered T-264/'Prins Bernhard' and due for a major service, was withdrawn from use in November 2019, prior to being transferred to its new owner, [[Omega Aerial Refueling Services]], an American defense contractor.<ref name="renamed_from_135542_on_20211122105829">{{cite web|url=https://www.flightglobal.com/fixed-wing/private-aerial-refueller-omega-buys-kdc-10-tankers-with-booms/135542.article|title=Private aerial refueller Omega buys KDC 10 tankers with booms|website=flightglobal.com|date=25 November 2019|access-date=21 November 2021}}</ref> The last KDC-10, registered T-235/'Jan Scheffer' remained in Dutch service until October 2021.<ref>{{cite web|url=https://www.aviacionline.com/2021/10/farewell-flight-and-final-goodbye-to-the-kdc-10-of-the-royal-netherlands-air-force/#:~:text=The%20Royal%20Netherlands%20Air%20Force%20(RNLAF)%20will%20bid%20farewell%20to,farewell%20tour%20of%20the%20Netherlands.|title=Farewell flight and final goodbye to the KDC-10 of the Royal Netherlands Air Force|website=aviacion.com|date=5 October 2021|access-date=21 November 2021}}</ref> The aircraft left The Netherlands bound for service with Omega in October 2021.<ref name="ai1219p7">{{Harvnb|van der Mark|2019|p=7}}</ref><ref name=key.aero/>

===Civilian operators===
[[File:Omega Tanker McDonnell Douglas DC-10-40 Avalon Vabre.jpg|thumb|right|Omega's KDC-10 tanker in March 2009]]

Commercial refueling companies Omega Aerial Refueling Services and Global Airtanker Service operate three KDC-10 tankers, N974VV, N235UL and N264DE, for lease.<ref>{{cite web |url=http://www.omegaairrefueling.com/FAQs.htm#Question3 |title=Frequently Asked Questions |work=Omega Air Refueling |access-date=27 August 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110728001046/http://www.omegaairrefueling.com/FAQs.htm#Question3 |archive-date=28 July 2011}}</ref><ref>{{cite web |url=http://www.globalairtankerservice.com/kdc10.html |title=KDC-10 Air Refueling Tanker Aircraft |url-status=dead |archive-url=https://web.archive.org/web/20080704101032/http://www.globalairtankerservice.com/kdc10.html |archive-date=4 July 2008 |website=Global Airtanker Service |access-date=19 September 2010}}</ref> They were converted from DC-10s and provide probe and drogue refueling capabilities from wing pods similar to the KC-10.<ref>{{cite web |url=http://www.globalairtankerservice.com/kdc10_po.html |title=KDC-10: Primary Options |url-status=dead |archive-url=https://web.archive.org/web/20080828111721/http://www.globalairtankerservice.com/kdc10_po.html |archive-date=28 August 2008 |website=Global Air Tanker Services |access-date=25 February 2008}}</ref>

In June and July 2011, Omega Air's KDC-10 supported three [[Royal Australian Air Force]]'s [[McDonnell Douglas F/A-18 Hornet|F/A-18 Hornets]], en route to [[Red Flag – Alaska]].<ref name="AFM282">"RAAF Hornets Participate in Red Flag Alaska" ''[[Air Forces Monthly]]'' ([[Key Publishing]]), Issue 282, September 2011, pp. 37. {{ISSN|0955-7091}}. Retrieved: 30 September 2011.</ref>

In 2019, Omega agreed to purchase the Netherlands' two KDC-10s. One was received in November 2019,<ref name=renamed_from_135542_on_20211122105829/> and the second delivered in October 2021.<ref name="ai1219p7"/><ref name=key.aero/>

==Variants==
*'''KC-10A''': Initial military tanker version based on the DC-10-30CF.
*'''KDC-10''': Conversion of DC-10-30CF aircraft to tanker/transport configuration. While a FMS program run through McDonnell Douglas, conversion of two aircraft was carried out by [[KLM]]. [[Omega Aerial Refueling Services]] now operates both former RNLAF KDC-10-30 aircraft and 1 KDC-10-40.{{citation needed|date=June 2023}}
*'''KC-10B''': After McDonnell Douglas did the KDC-10 conversion for the Royal Netherlands Air Force in 1992, they proposed a tanker/transport version of the [[McDonnell Douglas MD-11|MD-11CF]] which had the in-house designation KMD-11. MDC offered either conversion of second hand aircraft (KMD-11) or new build aircraft (KC-10B), the proposed KMD-11 offered 35,000 lb more cargo capacity and 8,400 lb more transferable fuel than the KC-10A. It was offered to the RNLAF and [[Royal Saudi Air Force]] (RSAF) in the 1990s and the [[Royal Australian Air Force]] (RAAF) in the early 2000s.<ref>{{cite web |url=http://www.avgeekery.com/why-wasnt-there-a-md-11-based-tanker/ |title=Too Big for Its Own Good: Why a MD-11 Based Tanker Was Never Built |date=8 January 2016}}</ref>

==Operators==
[[File:USAF KC-10 Extender takeoff at RAF Mildenhall.jpg|thumb|right|A KC-10 from Travis AFB taking off from [[RAF Mildenhall]]|alt=Large gray jet aircraft with three engines (two under the wings and one under the vertical stabilizer). The aircraft had just lifted off from runway, with landing gear fully extended.]]

* [[Omega Aerial Refueling Services]]

===Former===
;{{USA}}
*[[United States Air Force]] – Final KC-10 retired on 26 September 2024.<ref name="Retirement"/>
*[[Strategic Air Command]]
**[[2nd Bomb Wing]] – [[Barksdale AFB]], [[Louisiana]] 1981–1992
***[[2d Air Refueling Squadron]] 1989–1992
***[[32d Air Refueling Squadron]] 1981–1992
**4th Wing – [[Seymour-Johnson AFB]], [[North Carolina]] 1991–1992
***[[344th Air Refueling Squadron]]
***[[911th Air Refueling Squadron]]
**[[22d Air Refueling Wing]] – [[March AFB]], [[California]] 1982–1992
***[[6th Air Refueling Squadron]] 1989–1992
***[[9th Air Refueling Squadron]] 1982–1992
**68th Air Refueling Group/Wing – Seymour-Johnson AFB 1982–1991
***344th Air Refueling Squadron 1986–1991
***911th Air Refueling Squadron 1982–1991
**802d Air Refueling Wing – [[Lajes Air Base]], [[Azores]] 1990–1991
***802d Air Refueling Squadron
**1709th Air Refueling Wing – [[King Abdul Aziz Air Base]], [[Saudi Arabia]] 1990–1991
***1710th Air Refueling Squadron
*[[Air Mobility Command]]
**22d Air Refueling Wing – March AFB 1992–1994
***6th Air Refueling Squadron
***9th Air Refueling Squadron
**458th Operations Group – Barksdale AFB 1992–1994
***2d Air Refueling Squadron
***32d Air Refueling Squadron
**4th Operations Group – Seymour-Johnson AFB 1992–1995
***344th Air Refueling Squadron 1992–1994
***[[711th Air Refueling Squadron]] 1994–1994
***[[744th Air Refueling Squadron]] 1994–1995
***911th Air Refueling Squadron 1992–1994
**[[60th Air Mobility Wing]] – [[Travis AFB]], [[California]] 1994–2024
***[[6th Air Refueling Squadron]] 1995–2024
***[[9th Air Refueling Squadron]] 1994–2024
**[[305th Air Mobility Wing]] – [[McGuire AFB]], [[New Jersey]] 1994–2023
***[[2d Air Refueling Squadron]] 1994–2021
***[[32d Air Refueling Squadron]] 1994–2023
**[[380th Air Expeditionary Wing]] – [[Al Dhafra Air Base]], [[United Arab Emirates]] 2002–2023
***908th Expeditionary Air Refueling Squadron
**722d Air Refueling Wing – March AFB 1994–1996
***6th Air Refueling Squadron 1994–1996
***9th Air Refueling Squadron 1994
*[[Air Force Reserve Command]]
**98th Air Refueling Group (Associate) – Barksdale AFB 1987–1994
***78th Air Refueling Squadron
**452d Air Refueling Wing (Associate) – March AFB 1981–1995
***78th Air Refueling Squadron 1981–1987
***79th Air Refueling Squadron 1982–1995
**'''[[349th Air Mobility Wing]]''' (Associate) – Travis AFB 1994–2024
***'''[[70th Air Refueling Squadron]]''' 1994–2024
***'''[[79th Air Refueling Squadron]]''' 1995–2024
**[[514th Air Mobility Wing]] (Associate) – McGuire AFB 1994–2023
***[[76th Air Refueling Squadron]] 1994–2022
***[[78th Air Refueling Squadron]] 1994–2023
**916th Air Refueling Group (Associate) – Seymour-Johnson 1985–1994
***[[77th Air Refueling Squadron]]

;{{NLD}}
* [[Royal Netherlands Air Force]] operated two KDC-10s, which upon retirement were sold to [[Omega Aerial Refueling Services]]. The Dutch tankers were replaced by [[Airbus A330 MRTT]]s owned by [[NATO]] as part of the Multinational Multi-Role Tanker Transport Fleet (MMF).<ref name=MMF>{{cite web |title=MMF Background Paper |url=https://company.airbus.com/dam/assets/airbusgroup/int/en/news-and-media/Press-Releases-PDF/07-2016/Airbus-Defence-and-Space-welcomes-signing-of-contract-for-A330-MRTT-aircraft/MMF-Backgrounder/MMF%20Backgrounder.pdf |archive-url=https://archive.today/20170717223658/https://company.airbus.com/dam/assets/airbusgroup/int/en/news-and-media/Press-Releases-PDF/07-2016/Airbus-Defence-and-Space-welcomes-signing-of-contract-for-A330-MRTT-aircraft/MMF-Backgrounder/MMF%20Backgrounder.pdf |url-status=dead |archive-date=2017-07-17 |work=Airbus Group, retrieved from an Archive. today capture made on 17 Jul 2017 22:36:58 UTC |access-date=1 August 2021}}</ref> A DC-10 transport, registered T-255 served for three years before being withdrawn from service in April 2014 due to Dutch defence cuts.<ref>{{cite web |url=https://www.flightglobal.com/dutch-air-force-scraps-dc-10-transport/113013.article|title=Dutch air force scraps DC-10 transport|website=flightglobal.com|access-date=22 November 2021}}</ref>
** [[Structure of the Royal Netherlands Air Force#Air Mobility Command (AMC)|334 Squadron]] – [[Eindhoven Airport]]

==Incidents==
On 17 September 1987, KC-10A serial number ''82-0190'' was undergoing maintenance on the ground at [[Barksdale Air Force Base|Barksdale AFB]], [[Louisiana]], and suffered an explosion and subsequent fire. The KC-10 was significantly damaged and written off. One member of the ground crew died in the fire.<ref>[http://aviation-safety.net/database/record.php?id=19870917-1 "McDonnell Douglas KC-10A 82-0190."] ''[[Aviation Safety Network]] Database.'' Retrieved: 19 September 2010.</ref>

==Aircraft on display==
* 79-0433 – on static display at the [[Air Mobility Command Museum]] at [[Dover Air Force Base]], [[Delaware]]. It was the first KC-10 to be produced, and was used for testing and development before entering service in 1981.<ref name="Balik 2022 i273">{{cite web | last=Balik | first=Roland | title=AMC Museum receives USAF's first KC-10A Extender | website=U.S. Air Force Expeditionary Center | date=2022-04-26 | url=https://www.expeditionarycenter.af.mil/News/Article-Display/Article/3014847/amc-museum-receives-usafs-first-kc-10a-extender/ | access-date=2024-03-01}}</ref>
* 84-0185 – on static display at the [[March Field Air Museum]] at [[March Air Reserve Base]], [[Riverside, California|Riverside]], [[California]].<ref name="March Field Air Museum In Riverside, CA 2001 y816">{{cite web | title=KC-10A Extender, Boeing | website=March Field Air Museum In Riverside, CA | date=2001-09-11 | url=https://www.marchfield.org/aircraft/cargo/kc-10a-extender-boeing/ | access-date=2024-03-01}}</ref>
*84-0191 – on static display at the Air Park of the [[National Museum of the United States Air Force]] in [[Dayton, Ohio]].<ref name="National Museum of the United States Air Force™ 2024 v671">{{cite web | title=McDonnell Douglas KC-10A Extender | website=National Museum of the United States Air Force™ | date=2024-04-15 | url=https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/3742255/mcdonnell-douglas-kc-10a-extender/ | access-date=2024-04-18}}</ref>

==Specifications (KC-10A)==
{{Aircraft specs
|ref=USAF Fact sheet,<ref name=USAF_factht/> Steffen<ref name=steffen_p107>Steffen 1998, p. 107.</ref>
|prime units?=imp
<!--   General characteristics
-->
|crew= 4 (Aircraft Commander, copilot, flight engineer, and boom operator)
|capacity= 170,000 lb of cargo, 25 pallets and 16 passengers, or 17 pallets and 75 passengers<ref name=steffen_p107/>
|length ft=181
|length in=7
|length note=
|span ft=165
|span in=4.5
|span note=
|height ft=58
|height in=1
|height note=
|wing area sqft=3958
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil='''root:''' DSMA-496/-521/-522; '''tip:''' DSMA-519/-520<ref name="Selig">{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |access-date=16 April 2019}}</ref>
|empty weight lb=241027
|empty weight note=
|gross weight lb=590000
|gross weight note=
|max takeoff weight lb=590000
|max takeoff weight note=
|fuel capacity={{cvt|365000|lb|0}}
|more general=
<!--   Powerplant
-->
|eng1 number=3
|eng1 name=[[General Electric F103]] (GE CF6-50C2)
|eng1 type=[[turbofan]] engines
|eng1 lbf=52500
|eng1 note=
<!--   Performance
-->
|max speed mph=538
|max speed note=
|max speed mach=0.89
|cruise speed mph=
|cruise speed note=
|stall speed mph=
|stall speed note=
|never exceed speed mph=
|never exceed speed note=
|minimum control speed mph=
|minimum control speed note=
|range mi=4400
|range nmi=
|range note=with a maximum passenger capacity; {{cvt|3800|nmi|0}} with maximum cargo capacity.
|combat range miles=
|combat range note=
|ferry range miles=11500
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling ft=42000
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|glide ratio=<!-- sailplanes -->
|climb rate ftmin=6870
|climb rate note=
|time to altitude=
|sink rate ftmin=<!-- sailplanes -->
|sink rate note=
|lift to drag=
|wing loading lb/sqft=
|wing loading note=
|disk loading lb/sqft=
|disk loading note=
|fuel consumption lb/mi=
|power/weight=
|thrust/weight=

|more performance=<!--<br>
*'''Take-off run:''' {{cvt||ft|0}}
*'''Take-off distance to {{cvt|50|ft|0}}:''' {{cvt||ft|0}}
*'''Landing run:''' {{cvt||ft|0}}
*'''Landing distance from {{cvt|50|ft|0}}:''' {{cvt||ft|0}}-->

|avionics=
}}

==See also==
{{Portal|Aviation}}
{{aircontent
|related=
* [[McDonnell Douglas DC-10]]
|similar aircraft=
* [[Airbus A330 MRTT]]
* [[Boeing KC-767]]
* [[Lockheed TriStar (RAF)]]
|lists=
* [[List of active United States military aircraft]]
* [[List of United States military aerial refueling aircraft]]
|see also=
}}

==References==
;Notes
{{Reflist|group=N}}

;Citations
{{Reflist|30em}}

;Bibliography
{{Refbegin}}
* {{cite book|editor-last=Eden|editor-first=Paul|title=The Encyclopedia of Modern Military Aircraft|location=London|publisher=Amber Books|year=2004|isbn=978-1-904687-84-9}}
* {{cite book|last=Endres|first=Gunter|title=McDonnell Douglas DC-10, Volume 10|location=Grand Rapids, Michigan|publisher=Zenith Imprint|year=1998|isbn=978-0-7603-0617-8}}
* {{cite book|last=Frawley|first=Gerard|title=The International Directory of Military Aircraft, 2002–2003|location=Fyshwick, Australia|publisher=Aerospace Publications|year=2002|isbn=978-1-875671-55-7}}
* {{cite book|last=Steffen|first=Arthur A. C.|title=McDonnell Douglas DC-10 and KC-10 Extender|location=Hinckley, Leicester, UK|publisher=Midland Publishing|year=1998|isbn=978-1-85780-051-7}}
* {{cite magazine |last=van der Mark |first=Kees |title=First Dutch KDC-10 retired from service |magazine=[[Air International]] |date=December 2019 |volume=97 |issue=6 |page=7 |issn=0306-5634}}
* {{cite book|last1=Veronico|first1=Nick|last2=Dunn|first2=Jim|url=https://books.google.com/books?id=3zz3KLbOvYUC&q=E-3+Sentry&pg=PA83|title=21st Century U.S. Air Power|location=Grand Rapids, Michigan|publisher=Zenith Imprint|year=2004|isbn=978-0-7603-2014-3}}{{Dead link|date=May 2024 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{cite book|last=Waddington|first=Terry|title=McDonnell Douglas DC-10|location=Miami, Florida|publisher=World Transport Press|year=2000|isbn=978-1-892437-04-4}}
{{Refend}}

==External links==
{{Commons category|McDonnell Douglas KC-10 Extender}}
* [https://web.archive.org/web/20090531093126/http://www.boeing.com/defense-space/military/kc10/index.html KC-10 page on Boeing.com]
* [https://web.archive.org/web/20120719135258/http://www.af.mil/information/factsheets/factsheet.asp?id=109 USAF KC-10 fact sheet]
* [http://www.theaviationzone.com/factsheets/kc10.asp KC-10 fact sheet on TheAviationZone.com]
* [http://www.worldwide-military.com/Military%20Aircraft/Tankers/KDC-10_Algemene_info_english.htm KDC-10 in the Dutch Air Force]
* [https://web.archive.org/web/20101230190432/http://www.ts.northropgrumman.com/kc-10/index.html KC-10 CLS Competition]
* {{YouTube|XgjZul4P7X8|McDonnell Douglas promotional video of the KC-10 Extender}}

{{McDonnell Douglas aircraft}}
{{USAF transports}}
{{Authority control}}

[[Category:1980s United States military tanker aircraft]]
[[Category:Air refueling]]
[[Category:Trijets]]
[[Category:Low-wing aircraft]]
[[Category:Aircraft first flown in 1980]]
[[Category:McDonnell Douglas DC-10]]
[[Category:Aircraft with retractable tricycle landing gear]]