Editing Lockheed L-1011 TriStar (section)

===Production===
[[File:Pacific Southwest Airlines L-1011 N1079.jpg|thumb|left|An L-1011-1 of [[Pacific Southwest Airlines]] at Lockheed's Palmdale plant]]

The TriStar's [[List of Lockheed aircraft|internal Lockheed model number]] is L-093. The TriStar was manufactured in Lockheed facilities in Burbank and [[Palmdale, California]].

The prototype L1011 first flew on November 16, 1970.<ref name=David_Encyclo>{{cite book |editor-last= Donald |editor-first= David |chapter= Lockheed L-1011 TriStar |title= The Complete Encyclopedia of World Aircraft |location= New York |publisher= Barnes & Noble Books |year= 1997 |isbn= 0-7607-0592-5 |page= 579}}</ref> The L-1011 was certified on April 14, 1972, with the first airliner delivered to Eastern Air Lines on April 26, 1972.<ref name=David_Encyclo/> In 1972, its unit cost was US$20 million (~${{Format price|{{Inflation|index=US-GDP|value=20000000|start_year=1972}}}} in {{Inflation/year|US-GDP}}).<ref name=Flight10aug1972>{{cite magazine |url= https://www.flightglobal.com/pdfarchive/view/1972/1972%20-%202020.html |title= Airliner price index |magazine= Flight International |date= August 10, 1972 |page= 183}}</ref> To further publicize the new aircraft, an L-1011, possibly the prototype, was taken on a world tour during 1972 by famed Lockheed test pilot [[Tony LeVier]]. In a demonstration by test pilots LeVier and Charles Hall, 115 crew members, employees, and reporters embarked on the TriStar for a 4-hour, 13-minute flight from Palmdale to Dulles Airport "with the TriStar's AFCS [Automatic Flight Control System] feature engaged from takeoff roll to landing", and Lockheed touted it as "a groundbreaking moment: the first cross-country flight without the need for human hands on the controls".<ref name="auto"/>

Lockheed discovered fairly early on that the TriStar suffered from higher than estimated structural weight, engine weight, and specific fuel consumption. To rectify this problem and to meet performance guarantees, Lockheed developed a structural kit that allowed [[maximum takeoff weight]] (MTOW) to be increased on production aircraft from {{convert|409000|to|430000|lb|kg}}. However, the weight problems affected the weight and desirability of early production L-1011-1 aircraft, known as Group 1 (serial numbers 1002 through to 1012).{{cn|date=January 2023}}

Group 1 aircraft have an Operating empty weight ([[OEW]]) of {{convert|252700|lb|kg}}, about {{convert|12700|lb|kg}} higher than later aircraft, while Group 2 aircraft (serial numbers 1013 through 1051) have an OEW of {{convert|247000|lb|kg}}, some {{convert|4700|lb|kg}} lower. These aircraft, in general, also have different center of gravity envelopes with the forward center of gravity limit on the early aircraft being more restrictive at higher gross weights. Groups 1 and 2 aircraft (serial numbers 1002 to 1051) are upgradeable only to -50 or -150 specifications, although the Group 1 aircraft (up to serial number 1012) still maintain their operating disadvantages. All L-1011-1 aircraft from serial number 1052 onwards are Group 3 aircraft and are fully upgradeable to all variants up to -250 specification.

[[File:British Airways Lockheed L-1011-385-1 TriStar 1 Gilliand.jpg|thumb|[[British Airways]] L-1011 TriStar in Landor livery in 1986]]
Costs at Rolls-Royce were controlled and its efforts largely went into the original TriStar engines, which needed considerable modifications between the L-1011's first flight and service entry. The competition, notably General Electric, was very quick to develop its [[General Electric CF6|CF6]] engine with more thrust, which meant that a heavier "intercontinental" DC-10-30 could be more quickly brought to market. The flexibility afforded to potential customers by a long-range DC-10 put the L-1011 at a serious disadvantage. Rolls-Royce went on to develop the high-thrust [[Rolls-Royce RB211#RB211-524 series|RB211-524]] for the L-1011-200 and -500, but this took many years.<ref>{{cite book |chapter-url= http://www.emeraldinsight.com/Insight/viewContentItem.do?contentType=Article&hdAction=lnkpdf&contentId=1682587 |chapter= Engine Update |title= Aircraft Engineering and Aerospace Technology |volume= 48 |year= 1976 |page= 5}}</ref>

The resultant delay in Lockheed and Rolls-Royce offering a high gross variant with a longer range, coupled with the TriStar's delayed introduction, meant that only 250 TriStars were sold compared to over 400 DC-10s.<ref name="airlinereporter.com"/> Lockheed needed to sell 500 airliners to break even, but in 1981, the company announced production would end with the delivery of the 250th and last L-1011 on order in 1984.<ref>{{cite news |last= Jones |first= Jack |url= https://pqasb.pqarchiver.com/latimes/access/655488642.html?dids=655488642:655488642&FMT=ABS&FMTS=ABS:AI&type=historic&date=Dec+08%2C+1981&author=&pub=Los+Angeles+Times&desc=Saddened+Lockheed+Workers+Still+View+L-1011+With+Pride&pqatl=google |title= Saddened Lockheed workers still view L-1011 with pride |work= 'Los Angeles Times |date= December 8, 1981 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105084013/http://pqasb.pqarchiver.com/latimes/access/655488642.html?dids=655488642:655488642&FMT=ABS&FMTS=ABS:AI&type=historic&date=Dec+08,+1981&author=&pub=Los+Angeles+Times&desc=Saddened+Lockheed+Workers+Still+View+L-1011+With+Pride&pqatl=google |url-status= dead }}</ref><ref>{{cite news |url= https://news.google.com/newspapers?id=x6MiAAAAIBAJ&pg=3972,7629695&dq=lockheed+l-1011&hl=en |title= Lockheed to stop l-1011 production |work= Sumter Daily Item |date =December 8, 1981}}</ref>

The TriStar's failure to achieve profitability caused Lockheed to withdraw from the civilian aircraft business.<ref name="withdraw_from_civil_aviation"/> The TriStar's rivalry with the DC-10 has been seen as a "case study in what can happen when two manufacturers attempt to split a market that simply could not support both aircraft". Lockheed lacked the resources to follow up with several proposals based on the TriStar wing and airframe, including a wide-body twinjet and a stretched quad-jet (one of the quadjet proposals consisting of two underwing engines and two rear fuselage-mounted engines). McDonnell Douglas was also financially weakened and could only develop the [[McDonnell Douglas MD-11|MD-11]], a refinement of the DC-10, instead of an all-new design to challenge the next generation of twinjets like the [[Boeing 777]].<ref name="ReferenceA"/>

Ultimately, both the L-1011 and the DC-10/MD-11 were doomed by this next generation of widebody twinjets such as the Boeing 777 and the [[Airbus A330]] - as the rules on [[ETOPS]] gradually extended to longer distance routes - thanks largely to the improving reliability and performance of jet engines which made trijet aircraft less cost efficient to operate; widebody twinjets become the dominant configuration for long haul operations.