Editing McDonnell Douglas DC-10 (section)

===Background===
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 |image1 = McDonnell Douglas DC-10-30, Monarch Airlines JP342549.jpg
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 |image2 = S2-ACR final flight DC10 BHX FLIGHT BG8 (12732029803).jpg
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 |footer = The 3-4-3 (left) and 2-5-2 (right) seating configuration
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Following an unsuccessful proposal for the [[United States Air Force]]'s [[Lockheed C-5 Galaxy|CX-HLS (Heavy Logistics System)]] in 1965, [[Douglas Aircraft Company|Douglas Aircraft]] began design studies based on its CX-HLS submission. The aviation author John H. Fielder notes that the company was under competitive pressure to produce a [[wide-body aircraft]], having been somewhat slow in the previous decade to introduce its first [[jetliner]]s.<ref name="fielder 12">{{harvnb|Fielder|Birsch|1992|pp=1–2}}</ref><ref name="norriswagner 910">{{harvnb|Norris|Wagner|1999|pp=9–10}}</ref> In 1966, [[American Airlines]] offered a specification to manufacturers for a twin-engine wide-body aircraft smaller than the [[Boeing 747]] yet capable of flying similar long-range routes from airports with shorter runways; this specification would be highly influential in the design of what would become the DC-10.<ref name="norriswagner 34">{{harvnb|Norris|Wagner|1999|p=34}}</ref>{{sfn|Francillon|1990|pp=275–276}} It would become [[McDonnell Douglas]]'s first commercial [[airliner]] after the merger between [[McDonnell Aircraft Corporation]] and Douglas Aircraft Company in 1967.<ref name=Waddington_p06>{{harvnb|Waddington|2000|pp=6–18}}</ref><ref name="norriswagner 36">{{harvnb|Norris|Wagner|1999|p=36}}</ref>

An early DC-10 design proposal was for a four-engine double-deck wide-body jet airliner with a maximum seating capacity of 550 passengers and similar in length to a [[Douglas DC-8|DC-8]]. The proposal was shelved in favor of a trijet single-deck wide-body airliner with a maximum seating capacity of 399 passengers, and similar in length to the DC-8 Super 60.{{sfn|Endres|1998|p=13}} The choice of three engines was influenced by surveys of potential customers other than American Airlines, together with a desire to enhance [[hot and high]] climb performance after an engine failure—a serious concern at [[Stapleton International Airport]], which was heavily utilized by [[United Airlines]], one of the major anticipated buyers.{{sfn|Francillon|1990|p=276}} Large portions of the detailed design work, particularly that of the fuselage, were [[subcontract]]ed to external companies, such as the American aerospace company [[Convair]].<ref name="fielder 4165">{{harvnb|Fielder|Birsch|1992|pp=4, 165}}</ref> The legal relationship between McDonnell Douglas, Convair, and the [[Federal Aviation Administration]] (FAA) would later serve to complicate matters; specifically, Convair was forbidden from contacting the regulator no matter the severity of any safety concerns it had in the DC-10's design.<ref name="fielder 34">{{harvnb|Fielder|Birsch|1992|pp=3–4}}</ref>

McDonnell Douglas management became seriously concerned about the viability of the DC-10 after learning about the competing [[Lockheed L-1011 TriStar|Lockheed L-1011]], which was very similar and was being offered to the same customers.{{sfn|Francillon|1990|p=276}} On February 19, 1968, in what was supposed to be a knockout blow to [[Lockheed Corporation|Lockheed]], [[George A. Spater]], President of American Airlines, and [[James Smith McDonnell|James S. McDonnell]] of McDonnell Douglas announced American Airlines' intention to acquire the DC-10. This was a shock to Lockheed and there was general agreement within the U.S. aviation industry that American Airlines had left its competitors at the starting gate. According to Fielder, McDonnell Douglas had been urgently pursuing the DC-10's completion in light of the prospective competition and the high financial stakes involved.<ref name="fielder 2"/> Together with American Airlines' announcement of the DC-10 order, it was also reported that American Airlines had declared its intention to have the British [[Rolls-Royce RB211]] turbofan engine on its DC-10 airliners.<ref>{{harvnb|Porter|2013}}{{page needed|date=May 2023}}</ref> The DC-10 was first ordered by launch customers American Airlines with 25 orders, and United Airlines with 30 orders and 30 options in 1968.{{sfn|Endres|1998|p=16}}<ref>[https://news.google.com/newspapers?id=Yd0yAAAAIBAJ&sjid=0lwDAAAAIBAJ&pg=7174,6365434&dq=airbus&hl=en "American Orders 25 'Airbus' Jets."] {{Webarchive|url=https://web.archive.org/web/20211104142745/https://news.google.com/newspapers?id=Yd0yAAAAIBAJ&sjid=0lwDAAAAIBAJ&pg=7174,6365434&dq=airbus&hl=en |date=November 4, 2021}} ''St. Petersburg Times'', February 20, 1968. Accessed: May 7, 2022.</ref><ref name="norriswagner 38">{{harvnb|Norris|Wagner|1999|p=38}}</ref> The DC-10's similarity to the Lockheed L-1011 in design, passenger capacity, and launch date resulted in a sales competition that affected the profitability of both aircraft.<ref name="norriswagner 369">{{harvnb|Norris|Wagner|1999|pp=36–39}}</ref>