View source for McDonnell Douglas DC-9

{{Short description|Jet airliner, produced 1965-1982}}
{{Infobox aircraft
 |name= DC-9
 |image= Northwest N756NW DC9.JPG
 |caption= A [[Northwest Airlines]] DC-9 in 2007
 |type= [[Narrow-body aircraft|Narrow-body]] [[jet airliner]]
 |national_origin= United States
 |manufacturer= [[Douglas Aircraft Company]]<br />[[McDonnell Douglas]] (from Aug. 1967)
 |first_flight= February 25, 1965
 |introduction= December 8, 1965, with [[Delta Air Lines]]
 |retired=<!--Date the aircraft left service. If vague or more than a few dates, skip this -->
 |status= In limited service for cargo transport and private use
 |primary_user= [[USA Jet Airlines]] (historical)
 |more_users= [[Aeronaves TSM]] <br />[[Everts Air Cargo]] <br />[[Northwest Airlines]] (historical)<!-- Limit is three (3) users in 'more users' field, four (4) total users. Please separate with <br />.-->
 |produced= 1965–1982
 |number_built= 976
 |developed_from=
 |variants= [[McDonnell Douglas C-9]]
 |developed_into= [[McDonnell Douglas MD-80]] <br />[[McDonnell Douglas MD-90]] <br />[[Boeing 717]]
}}

The '''McDonnell Douglas DC-9''' is an American five-abreast, [[narrow-body aircraft|single-aisle aircraft]] designed by the [[Douglas Aircraft Company]]. It was initially produced as the '''Douglas DC-9''' prior to August 1967, after which point the company had merged with [[McDonnell Aircraft Corporation|McDonnell Aircraft]] to become [[McDonnell Douglas]].

Following the introduction of its first jetliner, the high-capacity [[DC-8]], in 1959, Douglas was interested in producing an aircraft suited to smaller routes. As early as 1958, design studies were conducted; approval for the DC-9, a smaller all-new jetliner, came on April 8, 1963. The DC-9-10 first flew on February 25, 1965, and gained its [[type certificate]] on November 23, to enter service with [[Delta Air Lines]] on December 8.

The DC-9 is powered by [[twinjet|two]] rear-mounted [[Pratt & Whitney JT8D]] low-bypass [[turbofan]] engines under a [[T-tail]] for a cleaner wing aerodynamic. It has a two-person flight deck and built-in [[airstair]]s to better suit smaller  airports. The aircraft was capable of taking off from 5,000 ft runways, connecting small cities and towns in the jet stream of air travel where jet service was previously impossible.  <!--variants-->
The Series 10 aircraft are 104&nbsp;ft (32 m) long for typically 90 coach seats. The Series 30, stretched by 15&nbsp;ft (4.5 m) to seat 115 in economy, has a larger wing and more powerful engines for a higher [[maximum takeoff weight]] (MTOW); it first flew in August 1966 and entered service in February 1967.
The Series 20 has the Series 10 fuselage, more powerful engines, and the Series 30's improved wings; it first flew in September 1968 and entered service in January 1969.
The Series 40 was further lengthened by 6&nbsp;ft (2 m) for 125 passengers, and the final DC-9-50 series first flew in 1974, stretched again by 8&nbsp;ft (2.5 m) for 135 passengers.
When deliveries ended in October 1982, 976 had been built.
Smaller variants competed with the [[BAC One-Eleven]], [[Fokker F28]], and [[Sud Aviation Caravelle]], and larger ones with the original [[Boeing 737]].

The original DC-9 was followed by the second generation in 1980, the [[McDonnell Douglas MD-80|MD-80]] series, a lengthened DC-9-50 with a larger wing and a higher MTOW. 
This was further developed into the third generation, the [[McDonnell Douglas MD-90|MD-90]], in the early 1990s, as the body was stretched again, fitted with [[V2500]] high-bypass turbofans, and an updated flight deck.
The shorter and final version, the MD-95, was renamed the [[Boeing 717]] after McDonnell Douglas's merger with Boeing in 1997; it is powered by [[Rolls-Royce BR715]] engines.
The DC-9 family was produced between 1965 and 2006 with a total delivery of 2441 units: 976 DC-9s, 1191 MD-80s, 116 MD-90s, and 155 Boeing 717s.
As of August 2022, 250 aircraft remain in service: 31 DC-9s (freighter), 116 MD-80s (mainly freighter), and 103 Boeing 717s (passenger), while the MD-90 was retired without freighter conversion.

==Development==

===Origins===
During the late 1950s, [[Douglas Aircraft Company|Douglas Aircraft]] studied a short- to medium-range airliner to complement their then-sole [[jetliner]], the high-capacity, long-range [[Douglas DC-8|DC-8]] (''DC'' stands for ''Douglas Commercial'').<ref>{{cite web |title= DC-1 Commercial Transport |url= http://www.boeing.com/history/mdc/dc-1.htm |publisher= Boeing |access-date= 27 March 2010 |archive-url= https://web.archive.org/web/20100207141221/http://boeing.com/history/mdc/dc-1.htm |archive-date= 7 February 2010 }}</ref> The ''Model 2067'', a four-engined aircraft sized for medium-range routes was studied in depth, but work on it was abandoned after the proposal did not receive enough interest from airlines. In 1960, Douglas signed a two-year contract with the French aeronautics company [[Sud Aviation]] for technical cooperation; under the terms of this contract, Douglas would market and support the [[Sud Aviation Caravelle]] and produce a [[licensed production|licensed version]] if sufficient orders were forthcoming from airlines. However, none were ever ordered from the company, leading to Douglas returning to its design studies after the co-operation deal expired.<ref name="G_Endres">Endres, Gunter. ''McDonnell Douglas DC-9/MD-80 & MD-90''. London: [[Ian Allan Publishing]], 1991. {{ISBN|0-7110-1958-4}}.</ref><ref name= "eden 81">Eden 2016, p. 81.</ref>

In 1962, design studies were underway into what would become the DC-9, known as Model 2086.<ref>{{cite journal|journal=[[Aviation Week & Space Technology]]|date=16 April 1962 |title=Douglas 2086 Fate Hinges on 125 Orders|url=https://archive.aviationweek.com/issue/19620416|page=40|volume=76|number=16|issn=0005-2175}}</ref> The first envisioned version seated 63 passengers and had a gross weight of 69,000&nbsp;lb (31,300&nbsp;kg). This design was changed into what would be the initial DC-9 variant.<ref name="G_Endres"/> During February 1963, detailed design work commenced.<ref name= "anderton 86"/> On April 8, 1963, Douglas announced that it would proceed with the DC-9.<ref name="G_Endres"/> Shortly thereafter, [[Delta Air Lines]] placed the initial order for the DC-9, ordering 15 aircraft along with options for another 15. By January 1965, Douglas had garnered orders for 58 DC-9 as well as options for a further 44.<ref name= "anderton 86"/>

Unlike the competing but larger [[Boeing 727]] [[trijet]], which used as many [[Boeing 707|707]] components as possible, the DC-9 was developed as an all-new design. Throughout its development, Douglas had placed considerable emphasis on making the airliner as economic as possible, as well as to facilitate its future growth.<ref name= "anderton 86"/> The adoption of the [[Pratt & Whitney JT8D]] low-bypass [[turbofan]] engine, which had already been developed for the Boeing 727, enabled Douglas to benefit from the preexisting investment.<ref name= "eden 114">Eden 2016, p. 114.</ref> Pratt & Whitney had long collaborated with Douglas on various projects, thus their engine was a natural choice for the company.<ref name= "vashjenkins 80">Vasigh, Taleghani and Jenkins 2012, p. 80.</ref> In order to reduce the considerable financial burden of its development, Douglas implemented one of the first [[Risk management|shared-risk production arrangement]]s for the DC-9, arranging for [[de Havilland Canada]] to produce the wing at its own financial cost in return for promises on prospective future production orders.<ref name= "anderton 86"/>

===Entry into service===
[[File:Left side view of Delta Air Lines Douglas DC-9 (N3304L) taking off.jpg|thumb|The DC-9 entered service with [[Delta Air Lines]] on December 8, 1965.]]

The pace of development on the program was rapid.<ref name= "eden 107">Eden 2016, p. 107.</ref> The first DC-9, a production model, flew on February 25, 1965.<ref name="aijun80 p293">''[[Air International]]'' June 1980, p. 293.</ref><ref name= "vashjenkins 79">Vasigh, Taleghani and Jenkins 2012, p. 79.</ref> The second DC-9 flew a few weeks later,<ref name="douglas_jetliners"/> with a test fleet of five aircraft flying by July. Several key refinements to the aircraft were made during flight testing, such as the replacement of the original [[leading-edge slat]] design to achieve lower [[Drag (physics)|drag]].<ref name= "Sadraey 239">Sadraey 2012, p. 239.</ref> The flight test program proceeded at a rapid pace; the initial Series 10 received [[Type certificate|airworthiness certification]] from the [[Federal Aviation Administration]] on November 23, 1965, permitting it to enter service with Delta Air Lines on December 8.<ref name="aijun80 p293"/><ref>Stretching out ''[[Airliner World]]'' October 2021 pages 104-112</ref>

Through the DC-9, Douglas had beaten rival company [[Boeing]] and their [[Boeing 737|737]] to enter the short-haul jet market, a key factor that contributed to the DC-9 becoming the best selling airliner in the world for a time.<ref name= "eden 112">Eden 2016, p. 112.</ref> By May 1976, the company had delivered 726 aircraft of the DC-9 family, which was more than double the number of its nearest competitor.<ref name= "anderton 86">Anderton 1976, p. 86.</ref> However, following decades of intense competition between the two airliners, the DC-9 would eventually be overtaken as the world's best selling airliner by Boeing's 737.<ref name= "eden 7">Eden 2016, p. 7.</ref><ref name= "vashjenkins 78">Vasigh, Taleghani and Jenkins 2012, p. 78.</ref>

From the onset of its development, the DC-9 had been intended to be available in multiple versions to suit varying customer requirements;<ref name= "aijun80 p292">''Air International'' June 1980, p. 292.</ref> the first stretched version, the Series 30, with a longer fuselage and extended wing tips, flew on August 1, 1966, entering service with [[Eastern Air Lines]] in 1967.<ref name= "aijun80 p293"/> The initial Series 10 was followed by the improved [[#Series 20|-20]], [[#Series 30|-30]], and [[#Series 40|-40]] variants. The final DC-9 series was the [[#Series 50|-50]], which first flew in 1974.<ref name= "douglas_jetliners"/>

===Production===
The DC-9 series, the first generation of the DC-9 family, would become a long term commercial success for the manufacturer. However, early production of the type had come at a higher unit cost than had been anticipated, leading to DC-9s being sold at a loss.<ref name= "eden 115">Eden 2016, p. 115.</ref> The unfavorable early economics of the type negatively impacted Douglas, pushing it into fiscal hardship. However, the high customer demand for the DC-9 made the company attractive for either an acquisition or a merger;<ref name= "vashjenkins 156">Vasigh, Taleghani and Jenkins 2012, pp. 15-16.</ref> Douglas would merge with the American aerospace company [[McDonnell Aircraft Corporation|McDonnell Aircraft]] to form [[McDonnell Douglas]] in 1967.<ref name= "eden 112"/><ref name= "norriswagner 36">Norris and Wagner 1999, p. 36.</ref>

The DC-9 family is one of the longest-lasting aircraft in production and operation. It was produced on the final assembly line in [[Long Beach, California]], beginning in 1965, and later was on a common line with the second generation of the DC-9 family, the [[McDonnell Douglas MD-80|MD-80]], with which it shares its line number sequence. Following the delivery of 976 DC-9s and 108 MD-80s, McDonnell Douglas stopped series production of the DC-9 in December 1982.<ref name= "douglas_jetliners"/> The last member of the DC-9 family, the Boeing 717, was produced until 2006.<ref name= "vashjenkins 78"/> The DC-9 family was produced in total {{#expr:979+1191+116+155}} units: 976 DC-9s (first generation), 1191 MD-80s (second generation), 116 MD-90s, and 155 Boeing 717s (third generation).<ref>{{cite web |url= http://www.boeing.com/commercial/#/orders-deliveries |title= Orders & Deliveries |publisher= Boeing}}</ref> This compared to 2,970 [[Airbus A320]]s and 5,270 [[Boeing 737]]s delivered as of 2006.<ref name="Airbus_O&D">{{Cite web |url= https://www.airbus.com/aircraft/market/orders-deliveries.html |title= Airbus Orders and Deliveries |date= 30 June 2022 |access-date= 8 July 2022 |url-status= live |archive-url= https://web.archive.org/web/20190210065631/https://www.airbus.com/aircraft/market/orders-deliveries.html |archive-date= 10 February 2019 |work= [[Airbus]] |format= XLS}}</ref><ref name= "Boeing_O&D">{{cite web |url= https://www.boeing.com/commercial/#/orders-deliveries |title= Boeing: Orders and Deliveries (updated monthly) |publisher= boeing.com |date= June 30, 2022 |access-date= July 12, 2022 |archive-date= January 12, 2021 |archive-url= https://web.archive.org/web/20210112224944/https://www.boeing.com/commercial/#/orders-deliveries |url-status= live }}</ref><!-- Unfair comparison as the production of the last member of the DC-9 family, the Boeing 717, ended in 2006. 

This compares to 8,000 Airbus A320s delivered as of February 2018<ref>{{cite news |url= https://www.flightglobal.com/news/articles/airbus-completes-8000th-a320-family-delivery-446191/ |title= Airbus completes 8,000th A320 family delivery |date= 23 Feb 2018 |first= Max |last= Kingsley-Jones |work=[[FlightGlobal]]}}</ref> and 10,000 [[Boeing 737]]s completed as of March 2018.<ref>{{cite news |url= https://www.flightglobal.com/news/articles/analysis-how-boeing-built-10000-737s-446735/ |title= How Boeing built 10,000 737s |date= 13 March 2018 |first= Max |last= Kingsley-Jones |work= Flightglobal}}</ref> -->

===Enhancement studies===
Studies aimed at further improving DC-9 [[fuel efficiency]], by means of retrofitted wingtips of various types, were undertaken by McDonnell Douglas, but these did not demonstrate significant benefits, especially with existing fleets shrinking. The wing design makes retrofitting difficult.<ref name= "Wingtip Mod">{{cite book |title= Assessment of Wingtip Modifications to Increase the Fuel Efficiency of Air Force Aircraft |url= http://books.nap.edu/openbook.php?record_id=11839&page=40 |year= 2007 |publisher= The National Academies Press |isbn= 978-0-309-10497-5 |page= 40 |doi= 10.17226/11839}}</ref> Between 1973 and 1975, McDonnell Douglas studied the possibility of [[re-engine| replacing engines]] on the DC-9 with the JT8D-109 turbofan, a quieter and more efficient variant of the JT8D. This progressed to the flight-test stage, and tests achieved noise reduction between 8 and 9 decibels depending on the phase of flight.<ref>{{cite tech report |author=Douglas Aircraft Company |date= 1 November 1973 |title= DC-9/JT8D Refan Phase 1 Final Report |url= https://ntrs.nasa.gov/api/citations/19740002616/downloads/19740002616.pdf |via=NASA Technical Report Server |publisher=NASA|page= 165 |id= NASA CR-121252 |access-date= 9 August 2022 |quote= }}</ref><ref>{{cite report |author=Douglas Aircraft Company |date= 1 July 1973 |title= DC-9/JT8D Refan Phase 1 Final Report |url= https://ntrs.nasa.gov/api/citations/19760005975/downloads/19760005975.pdf |via=NASA Technical Report Server |publisher=NASA |page= 2 |id= NASA CR-134860 |access-date= 9 August 2022 |quote= The noise reductions relative to the hardwall JT8D-9 were 8.2 EPNdB for takeoff with cutback and 8.7 EPNdB for landing approach.}}</ref> No further aircraft were modified, and the test aircraft was re-equipped with standard JT8D-9s prior to delivery to its airline customer.

===Further developments (DC-9 family)===
[[File:McDonnell Douglas MD-82 v1.0.png|thumb|upright=1.7|The DC-9 family development: the early DC-9, subsequent [[McDonnell Douglas MD-80|MD-80]], later [[McDonnell Douglas MD-90|MD-90]] and the final [[Boeing 717]]]]

Two further developments of the original or first generation DC-9 series used the new designation with McDonnell Douglas initials (MD- prefix) followed by the year of development. The first derivative or second generation was the [[McDonnell Douglas MD-80|MD-80 series]] and the second derivative or third generation was the [[McDonnell Douglas MD-90|MD-90 series]]. Together, they formed the DC-9 family of 12 aircraft members (variants), and if the DC-9- designation were retained, the family members would be: First generation (Series 10, Series 20, Series 30, Series 40, and Series 50), second generation (Series 81, Series 82, Series 83, Series 87, and Series 88), and third generation (Series 90 and Series 95). The Series 10 (DC-9-10) was the smallest family member and the Series 90 (MD-90) was the largest.

====Second generation (MD-80 series)====
{{main|McDonnell Douglas MD-80}}
The original DC-9 series was followed in 1980 by the introduction of the second generation of the DC-9 family, the MD-80 series. This was originally called the DC-9-80 (short Series 80 and later stylized Super 80).<ref name= "norriswagner 54">Norris and Wagner 1999, p. 54.</ref><ref name= "vashjenkins 16">Vasigh, Taleghani and Jenkins 2012, p. 16.</ref> It was a lengthened DC-9-50 with a higher [[maximum takeoff weight]] (MTOW), a larger [[wing]], new main [[landing gear]], and higher fuel capacity.<ref name= "eden 1135">Eden 2016, pp. 113-115.</ref> The MD-80 series features a number of variants of the JT8D turbofan engine that had higher thrust ratings than those available on the original DC-9 series.<ref name= "robertson 3115">Roberson 1997, p. 3-115.</ref> The MD-80 series includes the MD-81, MD-82, MD-83, MD-88, and shortest variant, the MD-87.

====Third generation (MD-90 series)====
{{main|McDonnell Douglas MD-90|Boeing 717}}

;MD-90
The MD-80 series was further developed into the third generation, the MD-90 series, in the early 1990s. It has yet another fuselage stretch, an [[electronic flight instrument system]] (first introduced on the MD-88), and completely new [[International Aero Engines V2500|International Aero V2500]] [[Turbofan#High-bypass turbofan|high-bypass turbofan engines]]. In comparison to the very successful MD-80, relatively few MD-90s were built.

; Boeing 717 (MD-95)
The shorter and final variant, the MD-95, was renamed the Boeing 717 after McDonnell Douglas's merger with Boeing in 1997 and before aircraft deliveries began.<ref name= "vashjenkins 69">Vasigh, Taleghani and Jenkins 2012, p. 69.</ref> The fuselage length and wing are very similar to those of the DC-9-30, but much use was made of lighter, modern materials. Power is supplied by two [[Rolls-Royce BR700|BMW/Rolls-Royce BR715]] high-bypass turbofan engines.

; Comac ARJ21 (C909)
China's [[Comac ARJ21]] (C909) is derived from the DC-9 family.{{cn|date=July 2024}} The ARJ21/C909 is built with manufacturing tooling from the MD-90 Trunkliner program. As a consequence, it has the same fuselage cross-section, nose profile, and tail.<ref>Burchell, Bill. [http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=om&id=news/om/2010/10/01/OM_10_01_2010_p33-252956.xml "Setting Up Support For Future Regional Jets"].{{dead link|date=November 2018}} Aviation Week & Space Technology, October 13, 2010.</ref>

==Design==
[[File:DC-9 Cockpit.jpg|right|thumb|A DC-9's two-person cockpit with analog instrument panel]]
[[File:The DC-9 Main Cabin (2170299582).jpg|thumb|The cabin of a former Northwest Airlines DC-9, showing a typical four-abreast seating in First Class and Five-abreast seating in economy class behind.]]

The DC-9 was designed for short to medium-haul routes, often to smaller airports with shorter runways and less ground infrastructure than the major airports being served by larger airliners like the Boeing 707 and Douglas DC-8, where accessibility and short-field characteristics were needed. The DC-9's takeoff weight was limited to 80,000&nbsp;lb (36,300&nbsp;kg) for a two-person flight crew by the then-[[Federal Aviation Administration|Federal Aviation Agency]] regulations at the time.<ref name= "G_Endres"/> The commercial passenger aircraft have five abreast layout for economy seating that can accommodate 80 to 135 passengers, depending on version and seating arrangement. Turnarounds were simplified by built-in airstairs, including one in the tail, which shortened boarding and deplaning times. The DC-9 was originally designed to perform a maximum of 40,000 landings.<ref name= "norriswagner 85">Norris and Wagner 1999, p. 85.</ref>

The DC-9 has two rear-mounted JT8D turbofan engines, relatively small, efficient wings, and a [[T-tail]].<ref name= "douglas_jetliners">Norris and Wagner 1999, {{page needed|date=May 2023}}.</ref> The tail-mounted engine design facilitated a clean wing without engine pods, which had numerous advantages. First, the [[flap (aircraft)|flaps]] could be longer, unimpeded by pods on the leading edge and engine-blast concerns on the trailing edge. This simplified design improved airflow at low speeds and enabled lower takeoff and approach speeds, thus lowering field length requirements and keeping wing structure light. The second advantage of the tail-mounted engines was the reduction in [[foreign object damage]] from ingested debris from runways and aprons, but with this position, the engines could ingest ice streaming off the wing roots. The third was the absence of engines in underslung pods, which permitted a reduction in fuselage ground clearance, making the airliner more accessible to baggage handlers and passengers. The cockpit of the DC-9 was largely analogue, with flight controls mainly consisting of various levers, wheels, and knobs.<ref name= "norriswagner 94">Norris and Wagner 1999, p. 94.</ref>

The problem of [[Stall (flight)#Deep stall|deep stalling]], revealed by the loss of the [[BAC One-Eleven]] prototype in 1963, was overcome through various changes, including the introduction of [[vortilon]]s, small surfaces beneath the wings' leading edges used to control airflow and increase low-speed lift.<ref name= "vortilon">{{cite journal |title= The DC-9 and the Deep Stall |journal= [[Flight International]] |date= 25 March 1965 |page= 442 |url= http://www.flightglobal.com/pdfarchive/view/1965/1965%20-%200804.html |access-date= 7 October 2011}}</ref><ref name= "norriswagner 24">Norris and Wagner 1999, p. 24.</ref> The need for such features is a result of the rear-mounted engines.<ref name= "Sadraey 248">Sadraey 2012, p. 248.</ref>

==Variants==
The DC-9 series, the first generation of the DC-9 family, includes five members or variants and 10 subvariants, which are the production versions (types). Their designations use the Series (DC-9-) prefix followed by a two-digit numbering with the same first digit and the second digit being a zero for variant names and a nonzero for version/type designations. The first variant, Series 10 (DC-9-10), has four versions (Series 11, Series 12, Series 14 and Series 15); the second variant, Series 20, has one version (Series 21); the third variant, Series 30, has four versions (Series 31, Series 32, Series 33 and Series 34); the fourth variant, Series 40, has one version (Series 41); and the fifth or final variant, Series 50, has one version (Series 51). 

===Series 10===
[[File:Republic Airlines DC-9-14; N8906E, August 1984 BUL (5553207548).jpg|thumb|[[Republic Airlines]] DC-9-14 (1984)]]

;Subvariant Series 11, Series 12, Series 14, Series 15
The original DC-9 (later designated the Series 10) was the smallest DC-9 variant. The -10 was {{convert|104.4|ft|abbr=on}} long and had a maximum weight of {{convert|82000|lb|abbr=on}}. The Series 10 was similar in size and configuration to the [[BAC One-Eleven]] and featured a T-tail and rear-mounted engines. Power was provided by a pair of {{convert|12500|lbf|kN|abbr=on|lk=on}} JT8D-5 or {{convert|14000|lbf|kN|abbr=on}} JT8D-7 engines. A total of 137 were built. [[Delta Air Lines]] was the initial operator.

The Series 10 was produced in two main subvariants, the Series 14 and 15, although, of the first four aircraft, three were built as Series 11s and one as Series 12. These were later converted to Series 14 standard. No Series 13 was produced. A [[Combi aircraft|combi]] version of the aircraft, with a {{convert|136|by|81|in|m|adj=on}} side cargo door forward of the wing and a reinforced cabin floor, was certificated on March 1, 1967. Combi versions included the Series 15MC (minimum change) with folding seats that can be carried in the rear of the aircraft, and the Series 15RC (rapid change) with seats removable on pallets. These differences disappeared over the years as new interiors were installed.<ref name= "airclaims"/><ref name= "JanesUp"/>

The Series 10 was unique in the DC-9 family in not having leading-edge slats. The Series 10 was designed to have short takeoff and landing distances without the use of leading-edge high-lift devices. Therefore, the wing design of the Series 10 featured airfoils with extremely high maximum-lift capability to obtain the low stalling speeds necessary for short-field performance.<ref>Shevell, Richard S. and Schaufele, Roger D., "Aerodynamic Design Features of the DC-9", AIAA paper 65-738, presented at the AIAA/RAeS/JSASS Aircraft Design and Technology Meeting, Los Angeles California, November 1965. Reprinted in the AIAA Journal of Aircraft, Vol.3 No.6, November/December 1966, pp. 515–523.</ref>

;Series 10 features
The Series 10 has an overall length of {{convert|104.4|ft|m|2}}, a fuselage length of {{convert|92.1|ft|m|2}}, a passenger-cabin length of {{convert|60|ft|m|2}}, and a wingspan of {{convert|89.4|ft|m|2}}.

The Series 10 was offered with the {{convert|14000|lbf|kN|abbr=on}}-thrust JT8D-1 and JT8D-7.<ref name= "airclaims"/><ref name= "JanesUp"/> All versions of the DC-9 are equipped with an AlliedSignal (Garrett) GTCP85 APU, located in the aft fuselage.<ref name= "airclaims"/><ref name= "JanesUp"/> The Series 10, as with all later versions of the DC-9, is equipped with a two-crew analog flightdeck.<ref name= "airclaims"/><ref name= "JanesUp"/>

The Series 14 was originally certificated with an MTOW of {{convert|85700|lb|abbr=on}}, but subsequent options offered increases to 86,300 and {{convert|90700|lb|abbr=on}}. The aircraft's MLW in all cases is {{convert|81700|lb|abbr=on}}. The Series 14 has a fuel capacity of 3,693 US gallons (with the 907 US gal centre section fuel). The Series 15, certificated on January 21, 1966, is physically identical to the Series 14 but has an increased MTOW of {{convert|90700|lb|abbr=on}}. Typical range with 50 passengers and baggage is {{Convert|950|nmi|abbr=~|lk=in}}, increasing to {{cvt|1278|nmi|}} at long-range cruise. Range with maximum payload is {{cvt|600|nmi}}, increasing to {{cvt|1450|nmi}} with full fuel.<ref name= "airclaims"/><ref name= "JanesUp"/>

The aircraft is fitted with a passenger door in the port forward fuselage, and a service door/emergency exit is installed opposite. An airstair installed below the front passenger door was available as an option as was an airstair in the tailcone. This also doubled as an emergency exit. Available with either two or four overwing exits, the DC-9-10 can seat up to a maximum certified exit limit of 109 passengers. Typical all-economy layout is 90 passengers, and 72 passengers in a more typical mixed-class layout with 12 first and 60 economy-class passengers.<ref name= "airclaims"/><ref name= "JanesUp"/>

All versions of the DC-9 are equipped with a tricycle undercarriage, featuring a twin nose unit and twin main units.<ref name= "airclaims"/><ref name= "JanesUp"/>

===Series 20===
[[File:SAS DC-9-21 SE-DBR.jpg|thumb|[[Scandinavian Airlines|SAS]] DC-9-21 (1982)]]
;Subvariant Series 21
The Series 20 was designed to satisfy a [[Scandinavian Airlines System|Scandinavian Airlines]] request for improved short-field performance by using the more-powerful engines and improved wings of the -30 combined with the shorter fuselage used in the -10. Ten Series 20 aircraft were produced, all as the Model -21.<ref>{{cite web |url= http://active.boeing.com/commercial/orders/index.cfm?content=userdefinedselection.cfm&pageid=m15527 |title= Boeing: Commercial |website= active.boeing.com}}</ref> The -21 had slats and stairs at the rear of plane.{{citation needed|date=October 2020}}

In 1969, a DC-9 Series 20 at Long Beach was fitted with an [[Elliott Brothers (computer company)|Elliott Flight Automation]] [[Head-up display]] by McDonnell Douglas and used for successful three-month-long trials with pilots from various airlines, the [[Federal Aviation Administration]], and the [[United States Air Force|US Air Force]].<ref>[http://www.flightglobal.com/pdfarchive/view/1969/1969%20-%200179.html "Air Transport: Head-Up Demonstration"]. ''Flight International'', Volume 95, No. 3125, 30 January 1969. p. 159.</ref>

;Series 20 features
The Series 20 has an overall length of {{convert|104.4|ft|m|2}}, a fuselage length of {{convert|92.1|ft|m|2}}, a passenger-cabin length of {{convert|60|ft|m|2}}, and a wingspan of {{convert|93.3|ft|m|2}}.<ref name= "airclaims"/><ref name= "JanesUp"/> The DC-9 Series 20 is powered by the {{convert|15000|lbf|kN|abbr=on}} thrust JT8D-11 engine.<ref name= "airclaims"/><ref name= "JanesUp"/>

The Series 20 was originally certificated at an MTOW of {{cvt|94500|lb}} but this was increased to {{cvt|98000|lb}}, eight percent more than on the higher weight Series 14s and 15s. The aircraft's MLW is {{cvt|95300|lb}} and MZFW is {{cvt|84000|lb}}. Typical range with maximum payload is {{cvt|1000|nmi}}, increasing to {{cvt|1450|nmi}} with maximum fuel. The Series 20, using the same wing as the Series 30, 40 and 50, has a slightly lower basic fuel capacity than the Series 10 (3,679 US gallons).<ref name= "airclaims"/><ref name= "JanesUp"/>

;Series 20 milestones
* First flight: September 18, 1968.
* FAA certification: November 25, 1968.
* First delivery: December 11, 1968, to [[Scandinavian Airlines System]] (SAS)
* Entry into service: January 27, 1969, with SAS.
* Last delivery: May 1, 1969, to SAS.

===Series 30===
[[File:Air Canada DC-9-32; CF-TLU@JFK, August 1968.jpg|thumb|[[Air Canada]] DC-9-32 (1968). This plane was later involved in the [[Air Canada Flight 797]] accident.]]

;Subvariant Series 31, Series 32, Series 33, Series 34
The Series 30 was produced to counter Boeing's 737 twinjet; 662 were built, about 60% of the total. The -30 entered service with [[Eastern Airlines]] in February 1967 with a {{convert|14|ft|9|in|abbr=on}} fuselage stretch, wingspan increased by just over {{convert|3|ft|1|abbr=on}} and full-span [[leading edge slats]], improving takeoff and landing performance. Maximum takeoff weight was typically {{convert|110000|lb|abbr=on}}. Engines for Models -31, -32, -33, and -34 included the P&W JT8D-7 and JT8D-9 rated at {{convert|14500|lbf|kN|abbr=on}} of thrust, or JT8D-11 with {{convert|15000|lbf|kN|abbr=on}}.

Unlike the Series 10, the Series 30 had leading-edge devices to reduce the landing speeds at higher landing weights; full-span slats reduced approach speeds by six knots despite 5,000&nbsp;lb greater weight. The slats were lighter than slotted [[Krueger flap]]s, since the structure associated with the slat is a more efficient torque box than the structure associated with the slotted Krueger. The wing had a six-percent increase in chord, all ahead of the front spar, allowing the 15 percent chord slat to be incorporated.<ref>Schaufele, Roger D. and Ebeling, Ann W., "Aerodynamic Design of the DC-9 Wing and High-Lift System", SAE paper 670846, presented at the Aeronautic & Space Engineering and Manufacturing Meeting, Los Angeles California, October 1967.</ref>

;Series 30 versions
The Series 30 was built in four main sub-variants.<ref name= "airclaims">Airclaims Jet Programs 1995</ref><ref name= "JanesUp">Jane's Civil and Military Aircraft Upgrades 1995</ref>

* '''DC-9-31''': Produced in passenger version only. The first DC-9 Series 30 flew on August 1, 1966, and the first delivery was to [[Eastern Airlines]] on February 27, 1967, after certification on December 19, 1966. Basic MTOW of {{convert|98000|lb|abbr=on}} and subsequently certificated at weights up to {{convert|108000|lb|abbr=on}}.
* '''DC-9-32''': Introduced in the first year (1967). Certificated March 1, 1967. Basic MTOW of {{convert|108000|lb|abbr=on}} later increased to {{convert|110000|lb|abbr=on}}. A number of cargo versions of the Series 32 were also produced:
** 32LWF (Light Weight Freight) with modified cabin but no cargo door or reinforced floor, intended for package freighter use.
** 32CF (Convertible Freighter), a combi version with a reinforced floor and removable passenger facilities
** 32AF (All Freight), a windowless all-cargo aircraft.
* '''DC-9-33''': Following the Series 31 and 32 came the Series 33 for combi or all-cargo use. Certificated on April 15, 1968, the aircraft's MTOW was {{convert|114000|lb|abbr=on}}, MLW to {{convert|102000|lb|abbr=on}} and MZFW to {{convert|95500|lb|abbr=on}}. JT8D-9 or -11 ({{convert|15000|lbf|kN|abbr=on}} thrust) engines were used. Wing incidence was increased 1.25 degrees to reduce cruise drag.<ref>Waddington, Terry, ''McDonnell Douglas DC-9; Great Airliners Series, Volume Four'', World Transport Press, Inc., 1998, p. 126. {{ISBN|978-0-9626730-9-2}}.</ref> Only 22 were built, as All Freight (AF), Convertible Freight (CF) and Rapid Change (RC) aircraft.
* '''DC-9-34''': The last variant was the Series 34, intended for longer range with an MTOW of {{convert|121000|lb|abbr=on}}, an MLW of {{convert|110000|lb|abbr=on}} and an MZFW of {{convert|98000|lb|abbr=on}}. The DC-9-34CF (Convertible Freighter) was certificated April 20, 1976, while the passenger followed on November 3, 1976. The aircraft has the more powerful JT8D-9s with the -15 and -17 engines as an option. It had the wing incidence change introduced on the DC-9-33. Twelve were built, five as convertible freighters.

;Series 30 features
The DC-9-30 was offered with a selection of variants of JT8D including the -1, -7, -9, -11, -15. and -17. The most common on the Series 31 is the JT8D-7 ({{convert|14000|lbf|kN|abbr=on}} thrust), although it was also available with the -9 and -17 engines. On the Series 32 the JT8D-9 ({{convert|14500|lbf|kN|abbr=on}} thrust) was standard, with the -11 also offered. The Series 33 was offered with the JT8D-9 or -11 ({{convert|15000|lbf|kN|abbr=on}} thrust) engines and the heavyweight -34 with the JT8D-9, -15 ({{convert|15000|lbf|kN|abbr=on}} thrust) or -17 ({{convert|16000|lbf|kN|abbr=on}} thrust) engines.<ref name= "airclaims"/><ref name= "JanesUp"/>

===Series 40===
[[File:NWA DC-9 at MSP (385589820).jpg|thumb|[[Northwest Airlines]] DC-9-40 (2007)]]
;Subvariant Series 41
The DC-9-40 is a further lengthened version.  With a {{convert|6|ft|6|in|0|abbr=on|adj=on}} longer fuselage, accommodation was up to 125 passengers. The Series 40 was fitted with Pratt & Whitney engines with thrust of {{convert|14500|to|16000|lbf|kN|abbr=on}}. A total of 71 were produced. The variant first entered service with [[Scandinavian Airlines System]] (SAS) in March 1968.
Its unit cost was {{AircraftCost|USA|5.2|m|year=1972|ref=<ref>{{cite magazine |url= https://www.flightglobal.com/pdfarchive/view/1972/1972%20-%202020.html |title= Airliner price index |magazine= Flight International |date= 10 August 1972 |page= 183}}</ref>}}.

===Series 50===
[[File:McDonnell Douglas DC-9-50 (6739882389).jpg|thumb|[[Delta Air Lines]] DC-9-51 (2012)]]

;Subvariant Series 51
The Series 50 was the largest version of the DC-9 to enter airline service. It features an {{convert|8|ft|2|in|abbr=on|adj=on}} fuselage stretch and seats up to 139 passengers. It entered revenue service in August 1975 with [[Eastern Airlines]] and included several detail improvements, a new cabin interior, and more powerful JT8D-15 or 17 engines in the {{convert|16000|and|16500|lbf|kN|abbr=on}} class. McDonnell Douglas delivered 96, all as the Model -51. Some visual cues to distinguish this version from other DC-9 variants include side strakes or fins below the side cockpit windows, spray deflectors on the nose gear, and thrust reversers angled inward 17 degrees compared to the original configuration. The thrust reverser modification was developed by [[Air Canada]] for its earlier aircraft, and adopted by McDonnell Douglas as a standard feature on the series 50. It was also applied to many earlier DC-9s during regular maintenance.<ref>{{Cite web |url=http://www.airlinercafe.com/page.php?id=396 |title=deviated |access-date=2016-09-27 |archive-date=2016-11-17 |archive-url=https://web.archive.org/web/20161117173148/http://www.airlinercafe.com/page.php?id=396 |url-status=dead }}{{unreliable source?|date=September 2016}}</ref>

===Military and government===
{{Further|McDonnell Douglas C-9}}
==Operators==
A total of 976 DC-9s were manufactured.<ref>Making the Mad Dog ''Airliner World'' November 2021 pages 48-52</ref>

As of May 2024, a total of 30 DC-9 series aircraft remain in service, of which 20 are operated by [[Aeronaves TSM]] and two passenger aircraft in service with [[African Express Airways]], and the rest in cargo service.{{cn|date=October 2024}}<!-- <ref>{{Cite web |url= https://www.flightglobal.com/asset/24536 |title= World Airline Census 2018 |website=[[FlightGlobal]]|language= en-GB |access-date= 26 August 2018}}</ref> -->

With the existing DC-9 fleet shrinking, modifications do not appear to be likely to occur, especially since the wing design makes retrofitting difficult.<ref name="Wingtip Mod"/>  DC-9s are therefore likely to be further replaced in service by newer airliners such as [[Boeing 737]], [[Airbus A320]], [[Embraer E-Jets]], and the [[Airbus A220]].<ref>[https://www.nytimes.com/reuters/business/business-airshow-bombardier.html "Bombardier Launches CSeries Jet"]. ''[[New York Times]]'' July 13, 2008.</ref> However one former [[Scandinavian Airlines]] DC-9-21 is operated as a skydiving jump platform at Perris Valley Airport in [[Perris, California]]. With the steps on the ventral stairs removed, it is the only airline transport class jet certified to date by the [[Federal Aviation Administration|FAA]] for skydiving operations as of 2006.<ref name= "Perris Valley Skydiving DC-9 Video">Perris Valley Skydiving DC-9 Video</ref> This is the last and only -21 series still airworthy, and after being out of service for over a decade, it returned to the sky on May 7th, 2024<ref>{{cite web | url=https://www.instagram.com/reel/C6rqf4hyc95/?igsh=MWQ1ZGUxMzBkMA== | title=Instagram }}</ref>

During the mid 1990s, [[Northwest Airlines]] was the largest operator of the type in the world, flying 180 DC-9s.<ref name= "norriswagner 23">Norris and Wagner 1999, p. 23.</ref> After its acquisition of Northwest Airlines, [[Delta Air Lines]] operated a sizable fleet of DC-9s, most of which were over 30 years old at the time. With severe increases in fuel prices in the summer of 2008, Northwest Airlines began retiring its DC-9s, switching to Airbus A319s that are 27% more fuel efficient.<ref>[https://www.nytimes.com/2008/06/11/business/11air.html "To Save Fuel, Airlines Find No Speck Too Small"]. New York Times, June 11, 2008.</ref><ref>Soaring Fuel Prices Pinch Airlines Harder, ''[[Wall Street Journal]]'' June 18, 2008, p. B1.</ref> As the Northwest/Delta merger progressed, Delta returned several stored DC-9s to service. Delta Air Lines made its last DC-9 commercial flight from Minneapolis/St. Paul to Atlanta on January 6, 2014, with the flight number DL2014.<ref>{{cite news |last= Trejos |first= Nancy |title= Delta DC-9 aircraft makes final flight |url= https://www.usatoday.com/story/todayinthesky/2014/01/07/delta-final-dc-9-flight/4351515/ |date= January 7, 2014 |newspaper= USA Today |access-date= January 16, 2014}}</ref><ref>{{cite news |url= http://www.cnn.com/2014/01/06/travel/delta-dc-9/index.html |work=[[CNN News]]|title= Delta retires last DC-9|date= January 7, 2014}}</ref>

===Deliveries===
{| class="wikitable" style="text-align:right; font-size:90%;"
|+ Deliveries<ref>[http://active.boeing.com/commercial/orders/index.cfm?content=userdefinedselection.cfm&pageid=m15527 Order and Deliveries – User Defined Reports.] Boeing</ref>
|-
! Type!!Total!!1982!!1981!!1980!!1979!!1978!!1977!!1976!!1975!!1974!!1973!!1972!!1971!!1970!!1969!!1968!!1967!!1966!!1965
|-
!DC-9-10
|'''113'''|| || || || || || || || || || || || || || ||10||29||69||5
|-
!DC-9-10C
|'''24'''|| || || || || || || || || || || || || || ||4||20|| ||
|-
!DC-9-20
|'''10'''|| || || || || || || || || || || || || ||9||1|| || ||
|-
!DC-9-30
|'''585'''||8||10||13||24||-||1||12||16||21||21||17||42||41||97||161||101|| ||
|-
!DC-9-30C
|'''30'''|| || || || ||1||-||6||-||-||-||4||1||3||5||7||3|| ||
|-
!DC-9-30F
|'''6'''|| || || || || || || || || || || || || ||4||2|| || ||
|-
!DC-9-40
|'''71'''|| || || ||5||6||3||2||4||27||-||3||2||7||2||10|| || ||
|-
!DC-9-50
|'''96'''|| ||5||5||10||15||18||28||15|| || || || || || || || || ||
|-
!C-9A
|'''21'''|| || || || || || || || || || ||8||1||-||5||7|| || ||
|-
!C-9B
|'''17'''||2||1||-||-||-||-||2||4||-||8|| || || || || || || ||
|-
!VC-9C
|'''3'''|| || || || || || || ||3|| || || || || || || || || ||
|-
!DC-9 series
|'''976'''||'''10'''||'''16'''||'''18'''||'''39'''||'''22'''||'''22'''||'''50'''||'''42'''||'''48'''||'''29'''||'''32'''||'''46'''||'''51'''||'''122'''||'''202'''||'''153'''||'''69'''||'''5'''
|}

==Accidents and incidents==
{{As of|2022|6}}, the DC-9 family aircraft has been involved in 276 major [[aviation accidents and incidents]], including 156 [[Hull loss|hull-losses]], with 3,697 fatalities combined (all generations of family members)= (1st gen., DC-9 series): 107 hull-losses & 2,250 fatalities + (2nd gen., [[McDonnell Douglas MD-80|MD-80]] series): 46 hull-losses & 1,446 fatalities + (3rd gen., [[McDonnell Douglas MD-90|MD-90]] series including [[Boeing 717]]): 3 hull-losses & 1 fatality.<ref>[http://aviation-safety.net/database/types/McDonnell-Douglas-DC-9-series/losses Accident summary hull-losses Douglas DC-9], [[Aviation Safety Network]]. Retrieved 19 July 2022.</ref><ref>[http://aviation-safety.net/database/types/McDonnell-Douglas-DC-9-series/statistics fatality statistics Douglas DC-9]. [[Aviation Safety Network]]. Retrieved 19 July 2022.</ref>

===Accidents with fatalities===
* On October 1, 1966, [[West Coast Airlines Flight 956]] crashed with eighteen fatalities and no survivors. This accident marked the first loss of a DC-9.<ref>{{cite web |title= Aircraft Accident Report. West Coast Airlines, Inc DC-9 N9101. Near Wemme, Oregon |url= http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR67-AF.pdf |author= [[National Transportation Safety Board]] |date= 11 December 1967 |access-date= 22 March 2009}}</ref>
* On March 9, 1967, [[TWA Flight 553]] crashed in a field in [[Concord Township, Champaign County, Ohio|Concord Township]], near [[Urbana, Ohio]], following a [[mid-air collision]] with a [[Beechcraft Baron]], an accident that triggered substantial changes in [[air traffic control]] procedures.<ref name= "AAR68-AI">{{cite web |title= Aircraft Accident Report. Trans World Airlines, Inc., Douglas DC-9, Tann Company Beechcraft Baron B-55 In-flight Collision near Urbana, Ohio, March 9, 1967 |url= http://www.airdisaster.com/reports/ntsb/AAR68-AI.pdf |author= [[National Transportation Safety Board]] |work= AirDisaster.Com |date= 19 June 1968 |access-date= 23 November 2008 |url-status= usurped |archive-url= https://web.archive.org/web/20081218011700/http://www.airdisaster.com/reports/ntsb/AAR68-AI.pdf |archive-date= December 18, 2008}}</ref> All 25 people on board the DC-9 and the sole occupant of the Beechcraft were killed.
* On March 27, 1968, [[Ozark Air Lines Flight 965]], a DC-9-15, collided with a [[Cessna 150|Cessna 150F]] while both aircraft were on approach to the same runway at [[Lambert Field]] in St. Louis, Missouri. The Cessna crashed, killing the two pilots aboard, while the DC-9 landed safely with no injuries to the 49 passengers and crew.<ref>{{cite report |url= https://www.fss.aero/accident-reports/dvdfiles/US/1968-03-27-US.pdf |title= Aviation Accident Report |publisher= National Transportation Safety Board |location= Washington, D.C. |docket= 1-0012 |date= June 30, 1969 |access-date= August 8, 2022 }}</ref>
* On March 16, 1969, [[Viasa Flight 742]], a DC-9-32, crashed into the La Trinidad neighborhood of [[Maracaibo, Venezuela]], during a failed take-off. All 84 people on board the aircraft, as well as 71 people on the ground, were killed. With 155 dead in all, this was the deadliest crash involving a member of the original DC-9 family, as well as the worst crash in civil aviation history at the time it took place.<!--The deadliest overall at that time was the 1968 Kham Duc C-130 shootdown, but that involved military aircraft as opposed to a civilian one.--><ref>{{cite magazine |url= http://content.time.com/time/magazine/article/0,9171,903063,00.html |title= DISASTERS: The Worst Ever |magazine= [[Time (magazine)|Time]]|date= 9 August 1971 |via= content.time.com}}</ref>
* On September 9, 1969, [[Allegheny Airlines Flight 853]], a DC-9-30, collided in mid-air with a [[Piper PA-28 Cherokee]] near [[Fairland, Indiana]]. The DC-9 carried 78 passengers and four crew members, the Piper, one pilot. Both aircraft were destroyed, and all occupants were killed.<ref name= "ntsb">[http://amelia.db.erau.edu/reports/ntsb/aar/AAR70-15.pdf NTSB Report (PDF)] {{webarchive |url= https://web.archive.org/web/20081218152920/http://amelia.db.erau.edu/reports/ntsb/aar/AAR70-15.pdf |date= 18 December 2008}}</ref><ref name= "pics">{{cite web |title= Allegheny 853 Crash Site Pictures |work= www.mcglaun.com |url= http://www.mcglaun.com/1969pics.htm |last= McGlaun |first= Dan |access-date= 27 January 2008}}</ref>
* On February 15, 1970, a [[Dominicana de Aviación]] DC-9-32 [[Dominicana DC-9 air disaster|crashed after taking off]] from [[Santo Domingo]]. The crash, possibly caused by contaminated fuel, killed all 102 passengers and crew, including champion boxer [[Carlos Cruz (boxer)|Teo Cruz]].<ref name= "ASN Dominicana">{{cite web |url= http://aviation-safety.net/database/record.php?id=19700215-0 |title= ASN Aircraft accident McDonnell Douglas DC-9-32 HI-177 Santo Domingo |author= D. Gero |work= [[Aviation Safety Network]] |publisher= [[Flight Safety Foundation]] |date= 21 May 2005 |access-date= 23 November 2008}}</ref><ref name= "ModestoBee">{{cite news |url= http://www.newspaperarchive.com/freepdfviewer.aspx?img=43102954 |title= Former Champ Teo Cruz Dies in Plane Crash |agency= [[Associated Press]] |work= [[Modesto Bee]] |location= [[Modesto, California]] |date= 16 February 1970 |page= A-6 |access-date= 23 November 2008}}</ref>
* On May 2, 1970, an [[Overseas National Airways]] DC-9-33 leased to [[ALM Antillean Airlines]] and operating as [[ALM Flight 980]] diverted to [[Saint Croix, U.S. Virgin Islands]], after three landing attempts in poor weather at [[Princess Juliana International Airport]] on [[Saint Maarten]]. The aircraft ran out of fuel 30&nbsp;mi (48&nbsp;km) short of St. Croix, [[water landing|ditched]] in the Caribbean Sea, sank in deep water after about ten minutes, and was never recovered. 40 people survived the ditching; 23 perished.<ref name= "AAR71-08">{{cite web |title= Aircraft Accident Report: Overseas National Airways, Inc., operating as Antilliaanse Luchtvaart Maatschappij Flight 980, near St. Croix, VirginIslands, May 2, 1970. DC-9 N935F. |url= http://www.airdisaster.com/reports/ntsb/AAR71-08.pdf |author= [[National Transportation Safety Board]] |work= AirDisaster.Com |date= 31 March 1971 |access-date= 23 November 2008 |url-status= usurped |archive-url= https://web.archive.org/web/20140322212243/http://www.airdisaster.com/reports/ntsb/AAR71-08.pdf |archive-date= 22 March 2014}}</ref>
* On November 14, 1970, [[Southern Airways Flight 932]], a DC-9, crashed into a hill near [[Tri-State Airport]] in Huntington, West Virginia. All 75 on board were killed (including 37 members of the [[Marshall University]] Thundering Herd football team, eight members of the coaching staff, 25 boosters, and others).
* On June 6, 1971, [[Hughes Airwest Flight 706]] was involved in a midair collision with a U.S. Marine Corps F-4 Phantom fighter. All 49 people on board the DC-9 died; one of two aboard the USMC aircraft ejected and survived.{{citation needed|date=April 2022}}
* On January 21, 1972, a [[Turkish Airlines]] DC-9-32 TC-JAC diverted to [[Adana]], [[Turkey]] after pressurization problems. The aircraft [[1972 Adana Turkish Airlines DC-9 crash|hit the ground]] during downwind on the 2nd approach and caught fire. There was one fatality, and four survivors.<ref>{{ASN accident |id= 19720121-0 |access-date= November 29, 2020 |title= TC-JAC}}</ref>
* On January 26, 1972, [[JAT Flight 367]] from [[Stockholm]] to [[Belgrade]], a DC-9-32, was destroyed in flight by a bomb placed on board. The sole survivor was a flight attendant, [[Vesna Vulović]], who holds the record for the world's longest fall without a parachute when she fell some {{convert|33000|ft|abbr=on}} inside a section of the airplane and survived.
* On March 19, 1972, [[EgyptAir Flight 763]], a DC-9-32, crashed into the Shamsam Mountains on an approach. All 30 passengers and crew members were killed.
* On May 30, 1972, [[Delta Air Lines Flight 9570]], a DC-9-14, crashed due to [[wake turbulence]] while attempting to land at [[Greater Southwest International Airport]] in Fort Worth behind a [[McDonnell Douglas DC-10]]. All 4 occupants aboard the DC-9 were killed. The accident prompted a pioneering FAA study into wake turbulence which resulted in the introduction of aircraft separation standards to mitigate its dangers.<ref>{{cite web |url=https://flightsafety.org/fsd/fsd_mar-apr02.pdf |title=Flight Safety Digest: Special Double Issue - Data Show That U.S. Wake-turbulence Accidents Are Most Frequent at Low Altitude and During Approach and Landing |date=March–April 2002 |access-date=April 4, 2025 |pages=9–10}}</ref>
* On December 20, 1972, [[North Central Airlines]] Flight 575, a DC-9-31, [[1972 Chicago–O'Hare runway collision|collided during its takeoff roll]] with [[Delta Air Lines]] Flight 954, a [[Convair CV-880]] ''N8807E'' that was taxiing across the same runway at [[O'Hare International Airport]] in Chicago. The DC-9 was destroyed, killing 10 and injuring 15 of the 45 people on board; two people among the 93 aboard the Convair 880 suffered minor injuries. Both aircraft [[Write-off|were written off]].<ref>{{cite web |url= http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR73-15.pdf |title= National Transportation Safety Board Report Number NTSB-AAR-73-15 "Aircraft Accident Report North Central Airlines, Inc., McDonnell Douglas DC-9-31, N954N, and Delta Air Lines, Inc., Convair CV-880, N8807E, O'Hare International Airport, Chicago, Illinois, December 20, 1972," adopted July 5, 1973}}</ref>
* On 5 March 1973, [[Iberia (airline)|Iberia]] Flight 504, a DC-9-32, flying from [[Palma de Mallorca Airport]] to [[Heathrow Airport]] when it [[1973 Nantes mid-air collision|collided in mid-air]] with [[Spantax]] Flight 400, a [[Convair 990 Coronado|Convair 990]]. All 68 people on board the DC-9 were killed. The CV-990 landed safely at [[Cognac – Châteaubernard Air Base]].<ref>{{ASN accident |id= 19730305-2 |access-date= November 29, 2020 |title= EC-BII}}</ref>
* On June 20, 1973, [[Aeroméxico Flight 229]], a DC-9-15, crashed into the side of a mountain on approach to [[Licenciado Gustavo Díaz Ordaz International Airport]] near Puerto Vallarta. All 27 passengers and crew members killed.
* On July 31, 1973, [[Delta Air Lines Flight 723]], a DC-9-31, crashed into a [[seawall]] at [[Logan International Airport]] in Boston, killing all 83 passengers and 6 crew members on board, including one passenger who initially survived but died months later.
* On September 11, 1974, [[Eastern Air Lines Flight 212]], a DC-9-30, crashed just short of the runway at [[Charlotte Douglas International Airport]], killing 72 out of the 82 occupants.
* On December 22, 1974, [[Avensa Flight 358]], a DC-9-14, crashed after takeoff from [[Maturín Airport]]. All 75 passengers and crew members died.
* On October 30, 1975, [[Inex-Adria Aviopromet Flight 450]], a DC-9-32, hit high ground in Prague while on approach to [[Prague Ruzyně Airport]]. 75 of the 120 people aboard were killed.<ref>{{cite web |url= http://aviation-safety.net/database/record.php?id=19751030-0 |title= ASN Aircraft accident McDonnell Douglas DC-9-32 YU-AJO Praha-Ruzyne International Airport (PRG) |first= Harro |last= Ranter |website= aviation-safety.net}}</ref>
* On September 10, 1976, [[Adria Airways|Inex-Adria Aviopromet]] Flight 550, a DC-9-31, [[1976 Zagreb mid-air collision|collided]] with [[British Airways]] Flight 476, a [[Hawker Siddeley Trident|Hawker Siddeley Trident 3B]], over the Croatian town of [[Vrbovec]], killing all 176 people aboard both aircraft.
* On April 4, 1977, [[Southern Airways Flight 242]], a DC-9-31, lost engine power while flying through a severe thunderstorm. During an attempted [[forced landing]] on a highway in [[New Hope, Paulding County, Georgia|New Hope, Georgia]], the jet struck roadside buildings, killing both pilots, 61 passengers, and 9 people on the ground. Both flight attendants and 20 passengers survived.<ref name= "AAR78-03">{{cite web |title= Aircraft Accident Report: Southern Airways, Inc. DC-9-31, N1335U. New Hope, Georgia. April 4, 1977. |url= http://www.airdisaster.com/reports/ntsb/AAR78-03.pdf |author= [[National Transportation Safety Board]] |work= AirDisaster.Com |date= 26 January 1978 |access-date= 2008-11-23 |url-status= usurped |archive-url= https://web.archive.org/web/20081218011715/http://www.airdisaster.com/reports/ntsb/AAR78-03.pdf |archive-date= December 18, 2008}}</ref><ref>{{cite magazine |url= http://www.slate.com/id/2247545/ |title= When Planes Land on Highways: The ins and outs of a surprisingly frequent phenomenon |first= Tom |last= Vanderbilt |magazine= Slate |date= 12 March 2010}}</ref>
* On June 26, 1978, [[Air Canada Flight 189]], a DC-9-32, overran the runway at [[Toronto Pearson International Airport]] during a [[rejected takeoff]] prompted by a blown tire. Two of the 107 passengers and crew were killed.<ref>{{cite news |url= https://www.theglobeandmail.com/servlet/ArticleNews/TPStory/LAC/20050803/PLANELASTIME03/TPNational/Canada |title= Takeoffs and landings always pose risk of calamity, as history shows |last= Priest |first= Lisa |author2= Rick Cash |work= [[Globe & Mail]] |location= [[Toronto]], Canada |date= 8 March 2005 |access-date= 23 November 2008 |quote= The last time an aircraft skidded off the runway in Toronto, seriously injuring passengers, was more than a quarter-century ago. On June 26, 1978, an Air Canada DC-9 skidded off a taxi strip at Toronto International Airport (what is today Pearson International Airport) during an aborted takeoff, then belly-flopped into a swampy ravine, killing two passengers and injuring more than a hundred others. |format= Fee required.}} {{Dead link |date= October 2010 |bot= H3llBot}}</ref>
* On December 23, 1978, [[Alitalia Flight 4128]] crashed in Tyrrhenian Sea which on approach to [[Rome Fiumicino Airport]], killed 108 of 129 passengers and crew members on board.
* On September 14, 1979, [[Aero Trasporti Italiani Flight 12]], a DC-9-32 crashed in the mountains near [[Cagliari]], Italy, while approaching [[Cagliari-Elmas Airport]]. All 27 passengers and 4 crew members died in the crash and ensuing fire.<ref name="ASN ATI 12">{{cite web |url= http://aviation-safety.net/database/record.php?id=19790914-1 |title= ASN Aircraft Accident description of the 14 SEP 1979 accident of a McDonnell Douglas DC-9-32 I-ATJC at Sarroch |work= [[Aviation Safety Network]] |publisher= [[Flight Safety Foundation]] |date= February 21, 2006 |access-date= 2008-11-23}}</ref>
[[File:Museo ustica.JPG|thumb|right|Itavia DC-9 (I-TIGI) was destroyed in an accident at Ustica. Shown in the "Museo della Memoria" opened in Bologna in 2007.]]
* On June 27, 1980, [[Itavia Flight 870]], DC-9-15 ''I-TIGI'', broke up mid-air after an explosion and crashed into the sea near the Italian island of [[Ustica]], killing all 81 people on board. The event spawned numerous [[conspiracy theories]], inconclusive investigations into an alleged cover-up by the Italian military, and one of the longest court inquiries in Italian history, which resulted in a 2013 ruling that the DC-9 was shot down by an [[air-to-air missile]] launched by a warplane, but without identifying who fired the missile or why.<ref name=NYT-Ustica>{{cite news |last=Povoledo |first=Elisabetta |date=10 February 2013 |title=Conspiracy Buffs Gain in Court Ruling on Crash |url=https://www.nytimes.com/2013/02/11/world/europe/itavia-flight-870-ruling-adds-support-to-a-theory.html |work=The New York Times |location=New York City |access-date=14 January 2023}}</ref> A popular theory endorsed by [[Giuliano Amato]] and [[Francesco Cossiga]], both former [[Prime Ministers of Italy]], says that the [[French Air Force]] shot down the DC-9 while trying to down a different aircraft carrying Libyan leader [[Muammar Gaddafi]], but no conclusive evidence of this has been presented.<ref name=NYT-Ustica/><ref>{{Cite web |date=2 September 2023 |last=Gavin |first=Gabriel |title=Italy ex-PM alleges France downed passenger jet in bid to kill Gaddafi |url=https://www.politico.eu/article/giuliano-amato-muammar-gaddafiv-itavia-flight-870/ |access-date=13 January 2024 |website=POLITICO |language=en}}</ref>
* On July 27, 1981, [[Aeroméxico Flight 230]], a DC-9-32 ran off the runway a [[Chihuahua International Airport]]. Thirty passengers and two crew of the 66 on board were killed. Bad weather and pilot error were the causes of the accident.
* On November 8, 1981, [[Aeroméxico Flight 110]], a DC-9-32, experienced a cabin decompression and crash near [[Zihuatanejo]] while initializing a emergency descent, killing all 18 passengers and crew members.
* On March 11, 1983, [[Avensa Flight 007]], a DC-9-32, landed hard at [[Barquisimeto Airport]], skidded off the runway and exploded, killing 23 of the 50 passengers and crew members.
* On June 2, 1983, [[Air Canada Flight 797]], a DC-9 experienced an electrical fire in the aft lavatory during flight, resulting in an emergency landing at [[Cincinnati/Northern Kentucky International Airport]]. During evacuation, the sudden influx of [[oxygen]] caused a [[flash fire]] throughout the cabin, resulting in the deaths of 23 of the 41 passengers, including [[Canadians|Canadian]] folk singer [[Stan Rogers]]. All five crew members survived.
* On December 7, 1983, in the [[Madrid runway disaster]], a departing [[Iberia (airline)|Iberia]] [[Boeing 727]] struck an [[Aviaco]] DC-9, causing the death of 93 passengers and crew. All 42 passengers and crew on board the DC-9 were killed.
* On December 20, 1983, [[Ozark Air Lines Flight 650]], a DC-9-31, struck a snowplow on landing at [[Sioux Falls Regional Airport]] in low visibility. The right wing was torn from the jet; the snowplow driver was killed and two flight attendants were injured. The accident was attributed to inadequate [[air traffic control]] (ATC) supervision of snow-clearing operations.<ref>{{Cite web|last=Ranter|first=Harro|title=ASN Aircraft accident McDonnell Douglas DC-9-31 N994Z Sioux Falls Regional Airport, SD (FSD)|url=https://aviation-safety.net/database/record.php?id=19831220-0|access-date=13 January 2024|website=aviation-safety.net|publisher=[[Aviation Safety Network]]}}</ref>
*On September 6, 1985, [[Midwest Express Airlines Flight 105]], operated with a DC-9-14, crashed just after takeoff from [[General Mitchell International Airport]] in Milwaukee. The crash was caused by improper control inputs by the flight crew after the number 2 engine failed, and all 31 aboard were killed.
* On August 31, 1986, Aeroméxico Flight 498 [[1986 Cerritos mid-air collision|collided in mid-air]] with a [[Piper Cherokee]] over the city of [[Cerritos, California]], then crashed into the city, killing all 64 aboard the aircraft, 15 people on the ground, and all three in the small plane.
* On April 4, 1987, [[Garuda Indonesia Flight 035]], a DC-9-32, hit a pylon and crashed on approach to [[Polonia International Airport]] in bad weather with 24 fatalities.<ref name= "ASN19870404-1">{{ASN accident |id= 19870404-1}}</ref>
* On November 15, 1987, [[Continental Airlines Flight 1713]], a DC-9-14, crashed on takeoff from [[Stapleton International Airport]] in bad weather with 28 fatalities. This accident was attributed to a combination of ATC confusion, exceeding the allowed time limit for takeoff after de-icing the wings, and inexperienced crew.
* On March 18, 1989, the main external cargo door of [[Evergreen International Airlines Flight 17]], a DC-9-33F freighter, opened shortly after takeoff from [[Carswell Air Force Base]]. The airliner crashed in [[Saginaw, Texas]], while attempting to return to Carswell, killing the two pilots. The accident was attributed to a loss of aircraft control. Contributing factors included a known electrical design flaw that caused the cockpit warning light to indicate that the door was latched properly when it was not; investigators faulted the FAA for not mandating corrective measures after similar incidents involving improperly latched DC-9 cargo doors.<ref>{{Cite web|last=|first=|date=April 23, 1990| title=Aircraft Accident Report: Evergreen International Airlines, McDonnell Douglas DC-9-33F, N931F, Saginaw, Texas, March 18, 1989|url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9002.pdf|archive-url=|archive-date=|access-date=April 2, 2025|website=|publisher=[[National Transportation Safety Board]]|id=NTSB/AAR-90/02}} - [https://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR90-02.pdf Copy at] [[Embry-Riddle Aeronautical University]].</ref>
* On November 14, 1990, [[Alitalia Flight 404]], a DC-9-32, crashed into a mountain on approach to [[Zurich Airport]] at night, killing all 46 persons on board. The crash was attributed to an [[instrument landing system]] receiver malfunction that caused incorrect altitude indications, the fact that the mountain was not lighted, and poor judgment by the pilots, particularly the captain's decision to disregard the first officer's concerns about incongruous altitude readings and continue the approach.<ref>{{cite web|date=January 27, 1993|access-date=April 7, 2025|title=Final Report of the Fédéral Aircraft Accidents Inquiry Board concerning the Accident of the aircraft DC-9-32, ALITALIA, Flight No AZ 404,I-ATJA on the Stadlerberg, Weiach/ZH, of 14 November 1990|url=https://www.sust.admin.ch/inhalte/AV-berichte/1457_e.pdf|url-status=live|publisher=Federal Aircraft Accidents Inquiry Board|archive-url=https://web.archive.org/web/20170812022935/https://www.sust.admin.ch/inhalte/AV-berichte/1457_e.pdf |archive-date=12 August 2017 }}</ref>
* On December 3, 1990, the pilots of Northwest Airlines Flight 1482, a DC-9-14, became disoriented in fog at [[Detroit-Metropolitan Wayne County Airport]], Michigan, and entered the active [[runway]] instead of the taxiway instructed by ATC; the jet was then [[1990 Wayne County Airport runway collision|struck by a departing Boeing 727]], killing nine.<ref name= "ASN NW 1482">{{cite web |url= http://aviation-safety.net/database/record.php?id=19901203-1 |title= ASN Aircraft accident Douglas DC-9-14 N3313L Detroit-Metropolitan Wayne County Airport, Michigan (DTW) |work= [[Aviation Safety Network]] |publisher= [[Flight Safety Foundation]] |date= 23 November 2008 |access-date= 23 November 2008}}</ref><ref name= "AAR 91-05">{{cite web |title= Aircraft Accident Report: Northwest Airlines Inc. Flights 1482 & 299, Runway Incursion and Collision, Detroit Metropolitan/Wayne County Airport, Romulus, Michigan, December 3, 1990 |url= http://www.airdisaster.com/reports/ntsb/AAR91-05.pdf |author= [[National Transportation Safety Board]] |work= AirDisaster.Com |date= 25 June 1991 |access-date= 23 November 2008 |url-status= usurped |archive-url= https://web.archive.org/web/20081218011728/http://www.airdisaster.com/reports/ntsb/AAR91-05.pdf |archive-date= December 18, 2008}}</ref>
* On February 17, 1991, [[Ryan International Airlines Flight 590]], a DC-9-15RC operating a mail flight, crashed on takeoff from [[Cleveland Hopkins International Airport]], killing both pilots. The accident was attributed to the pilots' failure to properly deice the aircraft, and to "a lack of appropriate response" by the FAA, Douglas, and the airline to "the known critical effect that a minute amount of ice contamination has on the stall characteristics of the DC-9 series 10 airplane."<ref name="AAR-91-09 Final report">{{cite web |date=November 16, 1991 |title=Ryan International Airlines, DC-9-15, N565PC, Loss of Control on Takeoff, Cleveland-Hopkins International Airport, Ohio, February 17, 1991 |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9109.pdf |access-date=April 2, 2025 |publisher=[[National Transportation Safety Board]] |id=NTSB/AAR-91/09 |archive-date=October 16, 2020 |archive-url=https://web.archive.org/web/20201016180007/https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9109.pdf |url-status=live }} – [http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR91-09.pdf Copy at] {{Webarchive|url=https://web.archive.org/web/20230307145546/http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR91-09.pdf |date=March 7, 2023 }} [[Embry–Riddle Aeronautical University]].</ref>
* On March 5, 1991, [[Aeropostal Alas de Venezuela Flight 108]], a DC-9-32, crashed into a mountainside in Trujillo, Venezuela, killing all 40 passengers and five crew aboard.<ref>{{ASN accident |id= 19910305-1 |access-date= November 29, 2020 |title= YV-23C}}</ref>
* On July 2, 1994, [[USAir Flight 1016]], a DC-9-31, crashed near Charlotte Douglas International Airport while performing a [[go-around]] prompted by heavy storms and [[wind shear]], killing 37 and injuring 15 aboard. Although the airplane crashed in a residential area with the tail section striking a house, there were no fatalities or injuries on the ground.
* On January 11, 1995, [[Intercontinental de Aviación Flight 256]], a DC-9-14, crashed in [[María La Baja]], Colombia, on approach to [[Rafael Núñez International Airport]], killing 51 of 52 passengers and crew members.
* On May 11, 1996, [[ValuJet Flight 592]], DC-9-32 N904VJ crashed in the [[Florida Everglades]] due to a fire caused by the activation of chemical oxygen generators illegally stored in the hold. The fire damaged the plane's electrical system and eventually overcame the crew, resulting in the deaths of all 110 people on board.
* On October 10, 1997, [[Austral Líneas Aéreas Flight 2553|Austral Flight 2553]], a DC-9-32, crashed near [[Fray Bentos]], Uruguay, killing all 69 passengers and five crew on board.<ref>{{cite web |url= http://aviation-safety.net/database/record.php?id=19971010-0 |title= ASN Aircraft accident McDonnell Douglas DC-9-32 LV-WEG Nuevo Berlin |date= 24 February 2008 |access-date= 27 May 2011 |publisher= [[Aviation Safety Network]]}}</ref>
* On February 2, 1998, [[Cebu Pacific Flight 387]], a DC-9-32, crashed on the slopes of [[Mount Sumagaya]] in [[Misamis Oriental]], Philippines, killing all 104 passengers and crew on board. Investigators deemed the incident to be caused by pilot error when the plane made a non-regular stopover to Tacloban.
* On November 9, 1999, [[TAESA Flight 725]] crashed a few minutes after leaving [[Uruapan International Airport]] en route to Mexico City. 18 people were killed in the accident.<ref>"[http://aviation-safety.net/database/record.php?id=19991109-0 ASN Aircraft accident McDonnell Douglas DC-9-31F XA-TKN Uruapan]." [[Aviation Safety Network]]. Retrieved on July 4, 2010.</ref>
* On October 6, 2000, [[Aeroméxico]] Flight 250, DC-9-31 ''N936ML'', overran the runway at [[General Lucio Blanco International Airport]] in Reynosa, crashed into houses, and fell into a canal; 4 on the ground were killed, but all 83 passengers and 5 crew survived. The accident was attributed to a late and excessively fast touchdown on a runway that was waterlogged due to heavy rainfall from [[Hurricane Keith]].<ref>{{cite web|url=http://aviation-safety.net/database/record.php?id=20001006-0 |title=ASN aircraft accident McDonnell Douglas DC-9-31 N936ML Reynosa General Lucio Blanco International Airport (REX)|website=Aviation Safety Network |access-date=January 14, 2024}}</ref>
* On 10 December 2005, [[Sosoliso Airlines Flight 1145]] crash-landed at [[Port Harcourt International Airport]], Nigeria. There were 108 fatalities and two survivors.<ref>{{ASN accident |id= 20051210-0 |access-date= November 29, 2020 |title= 5N-BFD}}</ref>
* On April 15, 2008, [[Hewa Bora Airways Flight 122]] crashed into a residential neighborhood, in the [[Goma]], Democratic Republic of the Congo,<ref>[http://www.cnn.com/2008/WORLD/africa/04/15/congo.crash/index.html "Plane crashes into African marketplace"] {{webarchive |url= https://web.archive.org/web/20080420090702/http://www.cnn.com/2008/WORLD/africa/04/15/congo.crash/index.html |date= April 20, 2008}}. CNN, April 15, 2008.</ref> resulting in the deaths of at least 44 people.<ref>[http://www.iht.com/articles/ap/2008/04/17/news/Congo-Plane-Crash.php "Toll from Congo plane crash rises to 44"]. ''Associated Press'', 2008-04-17</ref>
* On July 6, 2008, [[USA Jet Airlines Flight 199]], a DC-9-15F, crashed on approach to Saltillo, Mexico, after a flight from Shreveport, Louisiana. The captain died and the first officer was seriously injured.<ref>[http://aviation-safety.net/database/record.php?id=20080706-0 USA Jet Flight 199]. aviation-safety.net</ref>

===Hull losses===
* On December 27, 1968, [[Ozark Air Lines Flight 982]], a DC-9-15, crashed during takeoff at [[Sioux Gateway Airport]]. All 68 passengers and crew members survived, but 35 were injured. The accident was attributed to the pilots' failure to deice the wings and their selection of an improper takeoff thrust setting.<ref>{{Cite report |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR7020.pdf |title=Aircraft Accident Report |date=September 2, 1970 |publisher=[[National Transportation Safety Board]] |archive-url=https://web.archive.org/web/20190729053628/https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR7020.pdf |archive-date=July 29, 2019 |access-date=April 5, 2025|url-status=live}} {{PD-notice}} - [https://libraryonline.erau.edu:443/online-full-text/ntsb/aircraft-accident-reports/AAR70-20.pdf Copy at] [[Embry-Riddle Aeronautical University]].</ref>
* On November 27, 1973, [[Eastern Airlines]] Flight 300, a DC-9-31 [[aircraft registration|registered]] ''N8967E'', landed long at [[Akron-Canton Airport]] in light rain and fog, overran the runway, and went over an embankment. All 21 passengers and 5 crew survived with various injuries.<ref>{{ASN accident |id= 19731127-2 |access-date= October 29, 2020 |title= N8967E}}</ref>
* On February 21, 1986, [[USAir]] Flight 499, a DC-9-31 registered ''N961VJ'', landed long in low visibility and overran runway 24 at [[Erie International Airport]], coming to rest on a road. One passenger suffered minor injuries; the other 17 passengers and 5 crew were uninjured. The crash was attributed to the pilots' decisions to continue an excessively fast approach, and to land downwind in snow, which was prohibited on runway 24.<ref>{{cite web|url=https://app.ntsb.gov/pdfgenerator/ReportGeneratorFile.ashx?EventID=20001213X32835&AKey=1&RType=Final&IType=AA |title=NTSB Aviation Accident Final Report DCA86AA018 |publisher=[[National Transportation Safety Board]]|access-date= July 1, 2020}}</ref><ref>{{cite web|url=https://aviation-safety.net/database/record.php?id=19860221-0 |title=ASN aircraft accident McDonnell Douglas DC-9-31 N961VJ Erie International Airport, PA (ERI)|website=Aviation Safety Network|date=July 1, 2020 |access-date=July 1, 2020}}</ref>
* On April 18, 1993, [[Japan Air System Flight 451]], a DC-9-41, skidded off the runway at [[Hanamaki Airport]] after the inexperienced pilot mishandled a go-around attempt due to [[windshear]] and landed hard. There were 19 injuries in the crash and ensuing fire, but all 77 aboard survived.<ref name= "Avsafetynetwork">{{cite web |url= http://aviation-safety.net/database/record.php?id=19930418-0 |title= ASN Aircraft accident McDonnell Douglas DC-9-41 JA8448 Morioka-Hanamaki Airport (HNA) |first= Harro |last= Ranter |website= aviation-safety.net}}</ref>
<!-- Read [[WP:AIRCRASH-TYPEARTICLE]] before adding an [[Aviation accidents and incidents|aviation accident]]. -->

==Aircraft on display==
[[File:Sandro Pertini Spagna 1982.jpg|thumb|President of Italy [[Sandro Pertini]] with Italy's football team on board DC-9-32 MM62012 after winning the [[1982 World Cup]]. This aircraft is now preserved at [[Milan Malpensa Airport]].]]
===Canada===
* CF-TLL (cn 47021) – DC-9-32 on static display at the [[Canada Aviation and Space Museum]] in [[Ottawa]], Ontario, Canada.<ref>{{cite web |title= MCDONNELL DOUGLAS DC-9-32 |url= http://casmuseum.techno-science.ca/en/collection-research/artifact-mcdonnell-douglas-dc-9-32.php |access-date= 13 October 2016 |website= Canada Aviation and Space Museum |publisher= Canada Science and Technology Museums Corporation |archive-date= 10 June 2017 |archive-url= https://web.archive.org/web/20170610002342/http://casmuseum.techno-science.ca/en/collection-research/artifact-mcdonnell-douglas-dc-9-32.php }}</ref> It was previously operated by Air Canada.{{Cn|date=August 2024}}

===Czechia===
* N1332U (cn 47404) – DC-9-31 nose section preserved at industrial area in [[Liberec]], Czechia and rebuilt into flight simulator. The DC-9 was previously operated by Northwest.{{cn|date=February 2024}}

===Indonesia===
* PK-GNC (cn 47481) – DC-9-32 painted in [[Garuda Indonesia]]'s 1960s livery and put on display inside [[GMF AeroAsia|GMF]] hangar in [[Soekarno–Hatta International Airport|Soekarno-Hatta Airport]].<ref>{{Cite web |last= Nurhalim |first= Rendy |date= 27 October 2017 |title= Ada DC-9 Berlivery Klasik di Hanggar Garuda Maintenance Facility, Buat Apa Ya? |url= https://www.kabarpenumpang.com/ada-dc-9-berlivery-klasik-di-hanggar-garuda-maintenance-facility-buat-apa-ya/ |access-date= 26 December 2019 |website= KabarPenumpang.com |language= en-US}}</ref>
* PK-GNT (cn 47790) – DC-9-32 on static display at the Transportation Museum in [[Taman Mini Indonesia Indah]] in [[Jakarta, Indonesia]].<ref>{{cite web |title= Museum Transportasi |url= http://tamanmini.com/museum/museum-transportasi |access-date= 14 October 2016 |website= tmii |publisher= Taman Mini Indonesia Indah |language= id |archive-date= 30 March 2023 |archive-url= https://web.archive.org/web/20230330202738/https://www.tamanmini.com/museum/museum-transportasi |url-status= dead }}</ref> It was relegated to display status after suffering heavy damage in a landing accident in 1993.<ref>{{cite web |title= Accident description |url= http://aviation-safety.net/database/record.php?id=19930621-2 |access-date= 14 October 2016 |website= Aviation Safety Network }}</ref> It was previously operated by Garuda Indonesia.{{Cn|date=August 2024}}

===Italy===
* MM62012 (cn 47595) – DC-9-32 on static display at [[Volandia]] adjacent to [[Milan Malpensa Airport]]. This aircraft was operated by the [[Italian Air Force]] as a VIP transport, carrying the president of Italy among other duties.<ref>{{cite web |date= 29 October 2016 |title= IL DC9 PRESIDENZIALE A PORTATA DI MANO |url= http://volandia.it/dc9-portata-mano-cockpit-day-simulatore-frecce-tricolori |archive-url= https://web.archive.org/web/20161107023553/http://volandia.it/dc9-portata-mano-cockpit-day-simulatore-frecce-tricolori/ |archive-date= 7 November 2016 |access-date= 10 December 2016 |website= Volandia |language= it}}</ref><ref>{{cite news |date= 5 April 2016 |title= Portion of Historic DC-9 Donated to Volandia Museum |work= Warbirds News |url= http://www.warbirdsnews.com/aviation-museum-news/portion-historic-dc-9-donated-volandia-museum.html |access-date= 10 December 2016}}</ref>

===Netherlands===
* N929L (cn 47174) – DC-9-32 nose section displayed inside [[Amsterdam Airport Schiphol|Schiphol International Airport]]. Painted in [[KLM]] livery although the plane never served with the airline. It was previously used by [[Trans World Airlines|TWA]] and [[Delta Air Lines]].{{Cn|date=September 2024}}

===Mexico===
* XA-JEB – Ex Aeromexico DC-9-32 on display at a park in [[Cadereyta de Montes]], [[Querétaro]], Mexico. Formerly [[Hugh Hefner]]'s private jet, the 'Big Bunny', XA-JEB was sold in 1975 to Venezuela Airlines, who later sold it to Aeromexico, where it was operated until 2004. It was sold and placed on display in 2008 for use as an educational tool.<ref>{{cite web |last1= Svetkey |first1= Benjamin |date= 3 October 2017 |title= The Rise and Fall of the Big Bunny: What Happened to Hugh Hefner's Private Jet |url= https://www.hollywoodreporter.com/news/hugh-hefners-playboy-jet-big-bunny-inside-rise-fall-1045331 |access-date= 2 June 2019 |website= [[The Hollywood Reporter]]}}</ref>
* N942ML – with painted registration "XA-SFE" is found on the second floor of the Luxury shopping mall [[Centro Santa Fe|"Centro Comercial Santa Fe"]] in the [[Santa Fe, Mexico City|business district of Mexico City.]] It is on display with an [[Interjet]] livery for the Kidzania brand.{{Cn|date=September 2024}}
* N606NW – with painted registration "XA-MEX" can be found in Cuicuilo Plaza at the south of the city. Similar to "XA-SFE", it wears an Interjet Livery for the Kidzania brand.{{Cn|date=September 2024}}

===Spain===
[[File:At Gran Canaria 2021 0044.jpg|thumb|right|Preserved front section at Elder Museum, Canary Islands]]
* EC-BQZ (cn 47456) – DC-9-32 on static display at [[Adolfo Suárez Madrid–Barajas Airport]] in [[Madrid]].<ref>{{Cite web |last= |first= |date=2020-08-18 |title=Cuatro aviones Douglas DC-9 de Iberia volaron para Binter » Puente de Mando, por Juan Carlos Díaz Lorenzo |url=https://www.puentedemando.com/cuatro-aviones-douglas-dc-9-de-iberia-volaron-para-binter/ |access-date=2024-08-10 |website=Puente de Mando, por Juan Carlos Díaz Lorenzo |language=es}}</ref>
* EC-DGB – DC-9-34 front section only preserved at [[Elder Museum of Science and Technology]], Gran Canaria.{{cn|date=February 2024}}

===United States===
* N675MC (cn 47651) – DC-9-51 on static display at the [[Delta Flight Museum]] at [[Hartsfield–Jackson Atlanta International Airport]] in [[Atlanta]], [[Georgia (U.S. state)|Georgia]].<ref>{{cite web |title= McDonnell Douglas DC-9 Ship 9880 |url= http://www.deltamuseum.org/exhibits/exhibits/aircraft/mcdonnell-douglas-dc-9 |access-date= 14 October 2016 |website= Delta Flight Museum}}</ref> It arrived at the museum on 27 April 2014.<ref>{{cite web |last1= Meng |first1= Tiffany |date= 28 April 2014 |title= Two new planes |url= http://www.deltamuseum.org/about-us/blog/from-the-hangars/2014/04/28/two-new-planes |access-date= 14 October 2016 |website= Delta Flight Museum}}</ref> It was previously operated by Delta Air Lines.{{Cn|date=August 2024}}
* N779NC (cn 48101) – DC-9-51 was on static display at the [[Carolinas Aviation Museum]] at [[Charlotte Douglas International Airport]] in [[Charlotte, North Carolina]], until it was scrapped in January 2017.<ref>{{cite web |title= Delta Air Lines last DC-9, N779NC |url= http://www.carolinasaviation.org/commercial/delta-air-lines-dc-9 |archive-url= https://web.archive.org/web/20141006081514/http://www.carolinasaviation.org/commercial/delta-air-lines-dc-9 |archive-date= 6 October 2014 |access-date= 14 October 2016 |website= Carolinas Aviation Museum}}</ref> It was previously operated by Delta Air Lines.<ref>{{cite news |last1= Washburn |first1= Mark |date= 23 January 2014 |title= Delta's last DC-9 retires at Charlotte museum |work= CharlotteObserver.com |publisher= The McClatchy Company |url= http://www.charlotteobserver.com/2014/01/23/4635083/deltas-last-dc-9-retires-at-charlotte.html |access-date= 14 October 2016 |archive-url= https://web.archive.org/web/20140221202558/http://www.charlotteobserver.com/2014/01/23/4635083/deltas-last-dc-9-retires-at-charlotte.html |archive-date= 21 February 2014}}</ref>
* N782NC (cn 48107) – DC-9-51 on static display at [[Thief River Falls Regional Airport]] near [[Thief River Falls, Minnesota]]. It and N779NC were both flown from Atlanta to their final homes on January 23, 2014 after Delta Air Lines ceased DC-9 passenger operations with a flight from [[Minneapolis–Saint Paul International Airport]] to Atlanta on January 6, 2014.<ref>{{cite news|last=Bonham|first=Kevin|title=NCTC receives one of Delta's retired DC-9s for aviation program|url=https://www.grandforksherald.com/newsmd/nctc-receives-one-of-deltas-retired-dc-9s-for-aviation-program|newspaper=[[Grand Forks Herald]]|date=January 23, 2014|accessdate=April 28, 2025}}</ref>

==Specifications==
{{Overly detailed|section|nosplit=1|details=per [[WP:AIRMOS]], this section should cover the specifications of only a single variant|date=June 2025}}
{{citation style|section|reason=All page ranges must be preceded by the actual reference (since multiple sources are used here)|date=June 2025}}
{| class=wikitable style="text-align: center"
|+ DC-9 airplane characteristics<ref name= acaps>{{cite web |url= http://www.boeing.com/assets/pdf/commercial/airports/acaps/dc9.pdf |title= DC-9 airplane characteristics for airport planning |date= June 1984 |publisher= Douglas aircraft company}}</ref>
|-
! Variant
! -15 !! -21 !! -32 !! -41 !! -51
|-
! Cockpit crew<ref name= TCDS>{{cite web |url= http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/81bb7f7f3caf760686257ca80068d081/$FILE/A6WE_Rev_30.pdf |date= March 25, 2014 |title= Type Certificate Data Sheet no. A6WE |publisher= Federal Aviation Administration |access-date= October 27, 2014 |archive-date= December 28, 2016 |archive-url= https://web.archive.org/web/20161228113242/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/81bb7f7f3caf760686257ca80068d081/$FILE/A6WE_Rev_30.pdf }}</ref>{{rp|66}}
| colspan=5 | Two
|- 
! 1-class seating{{rp|15–18}}
| colspan=2 | 90Y @ 31–32"
| 115Y @ 31–33"
| 125 @ 31–34"
| 135 @ 32–33"
|-
! Exit limit<ref name=TCDS/>{{rp|80}}
| colspan=2 | 109
| 127
| 128
| 139
|-
! Cargo{{rp|4}}
| colspan=2 | 600&nbsp;ft<sup>3</sup> / 17.0 m<sup>3</sup>{{efn|name=15F|-15F{{snd}} cargo: 2,762&nbsp;ft<sup>3</sup> / 78.2&nbsp;m<sup>3</sup>, empty: 53,200&nbsp;lb / 24,131&nbsp;kg.}}
| 895&nbsp;ft<sup>3</sup> / 25.3&nbsp;m<sup>3</sup>{{efn|name=33F|-33F{{snd}} cargo: 4,195&nbsp;ft<sup>3</sup> / 119.0m<sup>3</sup>, empty: 56,430&nbsp;lb / 25,596&nbsp;kg.}}
| 1,019&nbsp;ft<sup>3</sup> / 28.9m<sup>3</sup>
| 1,174&nbsp;ft<sup>3</sup> / 33.2m<sup>3</sup>
|-
! Length{{rp|5–9}}
| colspan=2 | 104&nbsp;ft 4.8&nbsp;in / 31.82&nbsp;m
| 119&nbsp;ft 3.6 in / 36.36 m
| 125&nbsp;ft 7.2 in / 38.28 m
| 133&nbsp;ft 7 in / 40.72m
|-
! Wingspan{{rp|10–14}}
| 89&nbsp;ft 4.8 in / 27.25 m
| colspan=3 | 93&nbsp;ft 3.6 in / 28.44 m
| 93&nbsp;ft 4.2 in / 28.45 m
|-
! Height{{rp|10–14}}
| colspan=2 | 27&nbsp;ft 7 in / 8.4 m
| 27&nbsp;ft 9 in / 8.5 m
| 28&nbsp;ft 5 in / 8.7 m
| 28&nbsp;ft 9 in / 8.8 m
|-
! Width
| colspan=5 | 131.6 in / 334.3&nbsp;cm fuselage,{{rp|23}} {{#expr:49.2*2+24}} in / {{#expr:125*2+61}} cm cabin{{rp|24}}
|-
! [[Maximum take-off weight|Max. takeoff wt.]]{{rp|4}}
| 90,700&nbsp;lb / 41,141&nbsp;kg
| 98,000&nbsp;lb / 45,359&nbsp;kg
| 108,000&nbsp;lb / 48,988&nbsp;kg
| 114,000&nbsp;lb / 51,710&nbsp;kg
| 121,000&nbsp;lb / 54,885&nbsp;kg
|-
! Empty{{rp|4}}
| 49,162&nbsp;lb / 22,300&nbsp;kg{{efn|name=15F}}
| 52,644&nbsp;lb / 23,879&nbsp;kg
| 56,855&nbsp;lb / 25,789&nbsp;kg{{efn|name=33F}}
| 61,335&nbsp;lb / 27,821&nbsp;kg
| 64,675&nbsp;lb / 29,336&nbsp;kg
|-
! Fuel{{rp|4}}
| colspan=2 | 24,743&nbsp;lb / 11,223&nbsp;kg
| colspan=3 | 24,649&nbsp;lb / 11,181&nbsp;kg
|-
! Engine (2×)<ref name= TCDS/>
| [[JT8D]]-1/5/7/9/11/15/17
| -9/11
| -1/5/7/9/11/15/17
| -9/11/15/17
| -15/17
|-
! Thrust (2×)<ref name= TCDS/>
| colspan=5 | -1/7: {{cvt|14,000|lbf|kN}}, -5/-9: {{cvt|12,250|lbf|kN}}, -11: {{cvt|15,000|lbf|kN}}, -15: {{cvt|15,500|lbf|kN}}, -17: {{cvt|16,000|lbf|kN}}
|-
! Ceiling<ref name=TCDS/>{{rp|67}}
| colspan=5 | {{cvt|35000|ft|m}}
|-
! {{abbr|MMo|Maximum operating Mach number}}<ref name= TCDS/>
| colspan=5 | {{cvt|0.84|Mach|altitude_ft=35000|knots km/h mph|0}}
|-
! Range{{rp|36–45}}
| {{cvt|1300|nmi}}
| {{cvt|1500|nmi}}
| {{cvt|1500|nmi}}
| {{cvt|1200|nmi}}
| {{cvt|1300|nmi}}
|}
{{Notelist}}

==See also==
{{Portal|Aviation}}
{{aircontent
|see also=
* [[2006 Mexico DC-9 drug bust]]
* [[Airstair]]
|related=
* [[Boeing 717]]
* [[Comac ARJ21]]
* [[McDonnell Douglas C-9]]
* [[McDonnell Douglas MD-80]]
* [[McDonnell Douglas MD-90]]
|similar aircraft=
* [[BAC One-Eleven]]
* [[Boeing 737]]
* [[Dassault Mercure]]
* [[Fokker F28 Fellowship]]
* [[Hawker Siddeley Trident]]
* [[Sud Aviation Caravelle]]
* [[Tupolev Tu-134]]
|lists=
* [[List of civil aircraft]]
* [[List of jet airliners]]
}}
{{Clear}}

==References==

===Citations===
{{Reflist|30em}}

===Bibliography===
{{refbegin}}
* {{cite book |last= Anderton |first= David A. |url= https://books.google.com/books?id=nrAeLpAhgmsC |title= Progress in Aircraft Design Since 1903 |publisher= [[National Aeronautics and Space Administration]], Langley Research Center |year= 1976}}
* {{cite book |last= Becher |first= Thomas |title= Douglas Twinjets, DC-9, MD-80, MD-90 and Boeing 717 |location= Ramsbury, Marlborough, UK |publisher= [[Crowood Press]] |date= 2002 |isbn= 978-1-8612-6446-6}}
* {{cite book |last= Eden |first= Paul E. |url= https://books.google.com/books?id=duVgDwAAQBAJ |title= The World's Most Powerful Civilian Aircraft |publisher= Rosen Publishing |year= 2016 |isbn= 978-1-4994-6589-1}}
* {{cite book |last1= Norris |first1= Guy |first2= Mark |last2= Wagner |url= https://books.google.com/books?id=xAM5OpUZNswC |title= Douglas Jetliners |publisher= Zenith Imprint |year= 1999 |isbn= 978-1-61060-716-2}}
* {{cite book |last= Roberson |first= Patricia Q. |url= https://books.google.com/books?id=pY3fAAAAMAAJ |title= Aerospace Science: Frontiers of Aviation History |publisher= Air Force Reserve Officer Training Corps |date= 1997}}
* {{cite magazine |title= Super 80 For the Eighties |magazine= [[Air International]] |volume= 18 |number= 6 |date= June 1980 |pages= 267–272, 292–296 |issn= 0306-5634}}
* {{cite book |last= Sadraey |first= Mohammad H. |url= https://books.google.com/books?id=mmraQswlbMgC |title= Aircraft Design: A Systems Engineering Approach |publisher= Wiley |date= 2012 |isbn= 978-1-119-95340-1}}
* {{cite book |last= Taylor |first= John W. R. |author-link= John W. R. Taylor |title= Jane's All The World's Aircraft 1966–67 |location= London, UK |publisher= Sampson Low, Marston & Company |date= 1966}}
* {{cite book |last= Taylor |first= John W. R. |title= Jane's All The World's Aircraft 1976–77 |location= London, UK |publisher= Jane's Yearbooks |date= 1976 |isbn= 0-354-00538-3}}
* {{cite book |first1= Bijan |last1= Vasigh |first2= Reza |last2= Taleghani |first3= Darryl |last3= Jenkins |url= https://books.google.com/books?id=duKhyqEwEBgC |title= Aircraft Finance: Strategies for Managing Capital Costs in a Turbulent Industry |publisher= J. Ross Publishing |date= 2012 |isbn= 978-1-60427-071-6}}
{{refend}}

==External links==
{{Commons and category|McDonnell Douglas DC-9}}
* {{Cite web |url= https://www.boeing.com/history/products/dc-9.page |title= Boeing: Historical Snapshot: DC-9/C-9 Transport |archive-url= https://web.archive.org/web/20230610160632/https://www.boeing.com/history/products/dc-9.page |archive-date= June 10, 2023 |url-status=dead |df= mdy-all }}
* {{Cite web |url= http://www.boeing.com/history/mdc/dc-9.htm |title= DC-9 history page on Boeing.com |access-date= March 22, 2007 |archive-url= https://web.archive.org/web/20130304012919/http://www.boeing.com/history/mdc/dc-9.htm |archive-date= March 4, 2013 |df= mdy-all }}
* [https://web.archive.org/web/19970707062103/http://www.mdc.com/version2/history/comair4.htm McDonnell Douglas commercial history page for DC-9 series]
* [http://www.airliners.net/info/stats.main?id=276 DC-9-10/20/30 on Airliners.net] and [http://www.airliners.net/info/stats.main?id=277 DC-9-40/50 on Airliners.net]
* [https://web.archive.org/web/20130617210313/http://www.aviationhistoryonline.com/aircraft/index.php?id=34 DC-9 History on AviationHistoryOnline.com]

{{McDonnell Douglas DC-9 family}}
{{Douglas airliners}}
{{McDonnell Douglas timeline}}
{{Authority control}}

{{DEFAULTSORT:Mcdonnell Douglas DC-09}}
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[[Category:1960s United States airliners]]
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[[Category:Aircraft first flown in 1965]]
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