View source for Engineering:Lockheed L-1011 TriStar

{{Short description|American wide-body trijet airliner}}
<!-- This article is a part of Wikipedia:WikiProject Aircraft. Please see Wikipedia:WikiProject Aircraft/page content for recommended layout, and guidelines. -->
{|{{Infobox aircraft begin
 |name= L-1011 TriStar
 |image= File:11df - Delta Air Lines Lockheed L-1011 TriStar 1; N1732D@FLL;30.01.1998 (5016025629).jpg<!-- In-flight images are preferred for aircraft -->
 |caption= [[Company:Delta Air Lines|Delta Air Lines]] L-1011-1 TriStar
}}{{Infobox aircraft type
 |type= [[Engineering:Wide-body aircraft|Wide-body]] jet airliner
 |national origin= United States
 |manufacturer= [[Company:Lockheed Corporation|Lockheed Corporation]]
 |designer=
 |first flight= November 16, 1970
 |introduced= April 26, 1972, with Eastern Air Lines
 |retired= 
 |status= In limited service: one [[Engineering:Stargazer (aircraft)|Stargazer]]
 |primary user= [[Company:Northrop Grumman|Northrop Grumman]] <!--Limit one (1) primary user. Top 4 users listed in 'primary user' and 'more users' fields based on number of their fleets. -->
 |more users= {{Ubl
 |British Airways (historical)
 |[[Company:Delta Air Lines|Delta Air Lines]] (historical)
 |Eastern Air Lines (historical)<!-- Limit is four (4) in 'more users' field, four (4) total users with primary user. See Operators section below for others. Please separate with <br/>. -->
}}
 |produced= 1968–1984
 |number built= 250
 |variants with their own articles= {{Ubl
 |[[Engineering:Lockheed TriStar (RAF)|Lockheed TriStar (RAF)]]
 |[[Engineering:Stargazer (aircraft)|Stargazer (aircraft)]]
}}
}}
|}

The '''Lockheed L-1011 TriStar''' (pronounced "El-ten-eleven")<ref>{{Cite book |last=Simons |first=Graham M. |chapter-url=https://books.google.com/books?id=zwPMDwAAQBAJ&dq=lockheed+l-1011+pronounced&pg=PT274 |title=Colours in the Sky: The History of Autair and Court Line Aviation |date=2018-05-30 |publisher=Casemate Publishers |isbn=978-1-5267-2557-8 |pages= |language=en |chapter=9 – Enter The TriStar! |quote=the L-1011 (pronounced ‘Ell-ten-eleven) or TriStar, was a medium-to-long-range, wide-body trijet airliner}}</ref> is an American medium-to-long-range, wide-body [[Engineering:Trijet|trijet]] airliner built by the [[Company:Lockheed Corporation|Lockheed Corporation]]. It was the third wide-body airliner to enter commercial operations, after the [[Engineering:Boeing 747|Boeing 747]] and the [[Engineering:McDonnell Douglas DC-10|McDonnell Douglas DC-10]]. The airliner has a seating capacity of up to 400 passengers and a range of over {{convert|4000|nmi|sigfig=3|lk=on}}. Its trijet configuration has three [[Engineering:Rolls-Royce RB211|Rolls-Royce RB211]] engines with one engine under each wing, along with a third engine center-mounted with an [[Engineering:S-duct|S-duct]] air inlet embedded in the tail and the upper [[Engineering:Fuselage|fuselage]]. The aircraft has an [[Engineering:Autoland|autoland]] capability, an automated descent control system, and available lower deck [[Engineering:Galley (kitchen)|galley]] and lounge facilities.

The L-1011 TriStar was produced in two fuselage lengths. The original L-1011-1 first flew in November 1970 and entered service with Eastern Air Lines in 1972. The shortened, longer range L-1011-500 first flew in 1978 and entered service with British Airways a year later. The original-length TriStar was also produced as the high gross weight L-1011-100, the up-rated engine L-1011-200, and the further upgraded L-1011-250. Post-production conversions for the L-1011-1 with increased takeoff weights included the L-1011-50 and L-1011-150. 

The L-1011 TriStar's sales were hampered by two years of delays due to developmental and financial problems at Rolls-Royce, the sole manufacturer of the aircraft's engines. Between 1968 and 1984, Lockheed manufactured a total of 250 TriStars, assembled at the Lockheed plant located at the Palmdale Regional Airport in southern {{wipe|California}} north of {{wipe|Los Angeles}}. After L-1011 production ended, Lockheed withdrew from the commercial aircraft business due to its below-target sales.<ref name="withdraw_from_civil_aviation">{{cite magazine |last1= Greenwald |first1= John |first2= Jerry |last2= Hannifin |first3= Joseph J. |last3= Kane |name-list-style= amp |url= http://www.time.com/time/magazine/article/0,9171,925159,00.html |archive-url= https://web.archive.org/web/20071017194718/http://www.time.com/time/magazine/article/0,9171,925159,00.html |url-status= dead |archive-date= October 17, 2007 |title= Catch a Falling TriStar |magazine= {{wipe|Time (magazine)}} |date= December 21, 1981 |access-date= January 6, 2007}}</ref> As of 2024, only one L-1011 is in service, as [[Engineering:Stargazer (aircraft)|Stargazer]].

==Development==

===Origins===
In the 1960s, American Airlines approached Lockheed and competitor Douglas (later McDonnell Douglas) with the need for an airliner that could carry 250 passengers on transcontinental routes.<ref name="auto">{{Cite web |url=http://www.lockheedmartin.com/us/100years/stories/l-1011.html |title=L-1011: Luxury Among the Clouds|date=March 27, 2018}}</ref> Lockheed had not produced civilian airliners since 1961 with the [[Engineering:Lockheed L-188 Electra|L-188 Electra]]. In the 1950s the Electra was designed for turboprop propulsion, which Lockheed had successfully used on the [[Engineering:Lockheed C-130 Hercules|C-130 Hercules]] military transport. Even after the Electra overcame vibration problems that caused several crashes early in its career, the market for large airliners would soon shift over to jet airliners such as the [[Engineering:Boeing 707|Boeing 707]] and [[Engineering:Douglas DC-8|Douglas DC-8]].<ref>{{cite web |url= http://www.airdisaster.com/cgi-bin/view_details.cgi?date=09291959®=N9705C&airline=Braniff+Airlines |archive-url= https://archive.today/20120527061637/http://www.airdisaster.com/cgi-bin/view_details.cgi?date=09291959%C2%AE=N9705C&airline=Braniff+Airlines |archive-date= May 27, 2012 |title= Accident Synopsis 09291959 |work= AirDisaster.com |year= 2008 |url-status= usurped |access-date= July 16, 2011}}</ref><ref>{{cite web |url= http://www.hq.nasa.gov/office/pao/History/SP-440/ch6-5.htm |title= NASA Wind Tunnel Tests |publisher= National Aeronautics and Space Administration |access-date= July 16, 2011 |archive-date= October 30, 2011 |archive-url= https://web.archive.org/web/20111030224810/http://www.hq.nasa.gov/office/pao/History/SP-440/ch6-5.htm |url-status= dead }}</ref><ref>{{cite magazine |url= http://www.time.com/time/magazine/article/0,9171,895003,00.html |archive-url= https://web.archive.org/web/20090925184233/http://www.time.com/time/magazine/article/0,9171,895003,00.html |url-status= dead |archive-date= September 25, 2009 |title= Disasters: Electra's Tragedy |magazine= Time |date= October 17, 1960}}</ref> Lockheed won contracts for jet military transports with the C-141 StarLifter, and pioneered very large jet transports with the large C-5 Galaxy with its high-bypass turbofan engines. Boeing lost the military contract, but its private-venture 747 captured what would become a much larger civilian airliner market for [[Engineering:Wide-body aircraft|wide-body]] airliners.

Having experienced difficulties with some of its military programs, Lockheed was eager to re-enter the civilian market with a smaller wide-body jet, and its response was the L-1011 TriStar. Douglas Aircraft answered American Airlines with the [[Engineering:McDonnell Douglas DC-10|DC-10]], which had a similar three-engine configuration and dimensions.<ref name="Lockheed L-1011.">{{cite news |url= https://www.pbs.org/kcet/chasingthesun/planes/l1011.html |title= Lockheed L-1011 |work= Chasing the Sun |publisher= PBS |access-date= July 16, 2011}}</ref> Despite their similarities, the L-1011 and DC-10's engineering approach differed greatly. McDonnell, who had recently taken over Douglas Aircraft, directed DC-10 development on a "very firm budget, and cost overruns were unacceptable{{Snd}} even at the expense of safety", and the conservative approach meant reusing [[Engineering:Douglas DC-8|Douglas DC-8]] technology. By contrast, Lockheed would "take the most advanced technology of the day and when that technology was lacking, Lockheed created it" for the L-1011<ref name="ReferenceA">{{Cite web |url=http://www.airlinereporter.com/2015/09/requiem-trijet-masterpiece-lockheed-l-1011-tristar/ |title= Requiem for a Trijet Masterpiece - the Lockheed L-1011|date= September 30, 2015}}</ref> in order to give it lower noise emissions, improved reliability, and higher efficiency over first-generation jet airliners. The TriStar name was selected in a Lockheed employee naming contest for the airliner.{{citation needed|date=August 2017}} The advanced technology that went into the TriStar resulted in a high purchase price.{{cn|date=June 2022}}

The TriStar's design featured a twin-aisle interior with a maximum of 400 passengers and a three-engine layout. The TriStar was originally conceived as a "jumbo twin", but a three-engine design was ultimately chosen to give the aircraft enough thrust to take off from existing runways.<ref name="Lockheed L-1011."/> Also, before the establishment of Extended Operations standards by the FAA in the 1980s, commercial jets with only two engines were not allowed to fly more than 30 minutes away from an airport, making trans-oceanic flights impossible. The main visible difference between the TriStar and its similar trijet competitor, the McDonnell Douglas DC-10, is the central tail engine configuration: the DC-10's engine is mounted above the fuselage for simplicity of design and more economical construction, while the TriStar's engine is mounted to the rear fuselage and fed through an [[Engineering:S-duct|S-duct]] (similar to the [[Engineering:Boeing 727|Boeing 727]]) for reduced drag and improved stability.<ref name="airlinereporter.com">{{Cite web |url=http://www.airlinereporter.com/2014/03/lockheed-l1011-saying-goodbye-another-trijet/ |title= The Lockheed L1011 - Saying Goodbye to Another Trijet|date= March 24, 2014}}</ref><ref>{{cite book |url= https://books.google.com/books?id=bEdWAAAAMAAJ&q=s-duct |title= The Aeronautical Journal |volume= 78 |publisher= Royal Aeronautical Society |year= 1974 |pages= 392, 398 |access-date= July 16, 2011}}</ref> Lockheed engineers were able to maintain straight-through engine performance by limiting the curve of the S-duct to less than a quarter of the radius of the engine intake diameter. The S-duct design also reduced the total empty aircraft weight. The research undertaken during the design of the L-1011 indicated that losses of using an S-duct were more than compensated for by the above savings.<ref name="saeJournal">{{cite book |url= https://books.google.com/books?id=0GVTAAAAMAAJ&q=s-duct+ |title= SAE Transactions |publisher= Society of Automotive Engineers |date= 1970 |page= 1436 |access-date=December 11, 2008}}</ref> A further major difference between the L-1011 and the DC-10 was Lockheed's selection of the [[Engineering:Rolls-Royce RB211|Rolls-Royce RB211]] as the only engine for the L-1011.<ref>{{cite web |url= http://www.rolls-royce.com/civil_aerospace/technology/threeshaft.jsp |title= Three Shaft Engine Design |publisher= Rolls-Royce |archive-url= https://web.archive.org/web/20061016141514/http://www.rolls-royce.com/civil_aerospace/technology/threeshaft.jsp |access-date= July 16, 2011 |archive-date= October 16, 2006}}</ref><ref name="The_Magic_Of_A_Name">{{cite book |last= Pugh |first= Peter |title= The Magic of a Name: The Rolls-Royce Story, Part Two: The Power Behind the Jets |location= London |publisher= Icon Books |year= 2001 |isbn= 1-84046-284-1 |pages= 120–122}}</ref> As originally designed, the RB211 [[Engineering:Turbofan|turbofan]] was an advanced three-spool design with a carbon fiber fan,<ref>{{cite web |url= http://www.flightglobal.com/pdfarchive/view/1968/1968%20-%202418.html |title= The New Steel |work= Flight International |date= October 24, 1968}}</ref> which would have better efficiency and [[Engineering:Power-to-weight ratio|power-to-weight ratio]] than any competing engine like the [[Engineering:General Electric CF6|General Electric CF6]] that powered the DC-10. In theory, the triple spool would produce the same or more power as existing double spool engines while having a smaller cross section that would reduce drag.<ref name="ReferenceA"/><ref name="airlinereporter.com"/>

American Airlines opted for the Douglas DC-10, although it showed considerable interest in the L-1011. American intended to convince Douglas to lower its price for the DC-10, which it did.<ref>{{cite book |last= Boyne |first= Walter J. |title= Beyond the Horizons: The Lockheed Story |location= New York |publisher= St. Martin's Press |year= 1998 |isbn= 978-0-312-19237-2 |page= 354}}</ref> Without the support of American, the TriStar was launched on orders from TWA and Eastern Air Lines.{{citation needed|date = October 2023}}

[[File:Lockheed L-1011-1 Tristar, Lockheed JP5893645.jpg|thumb|Prototype L-1011 TriStar being prepared for its first flight test in 1970]]
Although the TriStar's design schedule closely followed that of its competitor, McDonnell Douglas beat Lockheed to market by a year due to delays in powerplant development. In February 1971, after massive development costs associated with the RB211, Rolls-Royce went into receivership.<ref>{{cite magazine |url= http://www.time.com/time/magazine/article/0,9171,904742,00.htm |archive-url= https://web.archive.org/web/20121107125907/http://www.time.com/time/magazine/article/0,9171,904742,00.htm |url-status= dead |archive-date= November 7, 2012 |title= Lockheed's Rough Ride with Rolls-Royce |magazine= Time |date= February 15, 1971}}</ref><ref>{{cite news |last= Wood |first= Robert |url= https://pqasb.pqarchiver.com/latimes/access/661257082.html?dids=661257082:661257082&FMT=ABS&FMTS=ABS:AI&type=historic&date=Nov+12%2C+1970&author=&pub=Los+Angeles+Times&desc=Jumbo+Jet+Engines+for+Lockheed+Push+Rolls-Royce+in+Red&pqatl=google |title= Jumbo Jet engines for Lockheed push Rolls-Royce in red |work= Los Angeles Times |date= November 12, 1970 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105083855/http://pqasb.pqarchiver.com/latimes/access/661257082.html?dids=661257082:661257082&FMT=ABS&FMTS=ABS:AI&type=historic&date=Nov+12,+1970&author=&pub=Los+Angeles+Times&desc=Jumbo+Jet+Engines+for+Lockheed+Push+Rolls-Royce+in+Red&pqatl=google |url-status= dead }}</ref> This halted L-1011 final assembly and Lockheed investigated the possibility of a US engine supplier.<ref>{{cite news |last= Lindsey |first= Robert |url= https://www.nytimes.com/1971/02/05/archives/lockheed-seeks-us-engine-now-retooling-cost-of-a-switch-could-run.html |title= Lockheed Seeks U.S. Engine Now: Retooling Cost of a Switch Could Run to $100-million |work= The New York Times |date= February 5, 1971}}</ref> However the engineering was finalized at that stage in the TriStar's development and its S-duct, which was designed to fit the smaller cross-section of the triple spool RB-211 engine that would have reduced drag, was too small in diameter to accommodate an existing double spool engine.<ref name="airlinereporter.com"/> One option presented was potential outsource of RB-211 production to Canadian manufacturer Orenda Engines.<ref>{{cite news |url= https://news.google.com/newspapers?id=tK4tAAAAIBAJ&pg=2030,1953777&dq=l-1011+international&hl=en |title= Canadian 'key' has no plans |work= Montreal Gazette |date= February 9, 1971}}</ref>

The British government agreed to approve a large state subsidy to restart Rolls-Royce operations on condition the U.S. government guarantee the bank loans Lockheed needed to complete the L-1011 project.{{refn|The British government did approve a large state subsidy because if Lockheed (which was itself weakened by the difficulties) had failed, the market for the RB211 would have evaporated.<ref>{{cite news |last= Lewis |first= Antony |url= https://www.nytimes.com/1970/11/12/archives/british-grant-set-for-rollsroyce-government-to-spend-up-to.html |title= British Grant Set for Rolls-Royce: Government to Spend up to $100-Million in Rescue Bid |work= The New York Times |date= November 12, 1970}}</ref>|group=Note}} Despite some opposition, not least from the then Governor of California, Ronald Reagan, the U.S. government provided these guarantees.<ref name="loan_guarantee">{{cite magazine |url= http://www.time.com/time/magazine/article/0,9171,944387,00.html |archive-url= https://web.archive.org/web/20070930044753/http://www.time.com/time/magazine/article/0,9171,944387,00.html |url-status= dead |archive-date= September 30, 2007 |title= New Life for TriStar |magazine= Time |date= May 17, 1971 |access-date= July 16, 2011}}</ref> For the rest of the RB211 project, Rolls-Royce remained a government-owned company.<ref>{{cite news |url= https://news.google.com/newspapers?id=HpkuAAAAIBAJ&pg=5363,2738212&dq=rolls-royce+lockheed&hl=en |title= Rolls-Royce Still Alive and Kicking |work= Montreal Gazette |date= February 18, 1972}}</ref>

===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 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 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 [[Engineering:Maximum takeoff weight|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 [[Engineering: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 [[Engineering: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 some 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 [[Engineering: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 [[Engineering:Boeing 777|Boeing 777]].<ref name="ReferenceA"/>

==Design==
[[File:Lockheed L-1011 Tristar simulator cockpit RAF museum.jpg|thumb|The L-1011 TriStar's three-crew flight deck]]
[[File:TWA Lockheed L-1011 Tristar coach cabin.jpg|thumb|Coach cabin of a TWA L-1011 TriStar in 2–5–2 layout]]

=== Engines ===
The [[Engineering:Rolls-Royce RB211|RB211]] and its features, despite the delays in its development, provided the L-1011 with then-unmatched fuel economy and noise levels.<ref name=":0">{{Cite book|last=Upton, Jim.|url=https://www.worldcat.org/oclc/48491576|title=Lockheed L-1011 Tristar|date=2001|publisher=Specialty Press Publishers and Wholesalers|isbn=1-58007-037-X|location=North Branch, MN|oclc=48491576}}</ref>{{Rp|23}}

==== Reversers and nozzle ====
During development the RB211 engines on the L-1011 had ''thrust-spoilers'' – [[Engineering:Target-type thrust reversal|target-type]] hot-stream reverse buckets – alongside the cold-bypass reversers. Despite capturing 25% of the total engine thrust, aerodynamic interference with the flaps diminished the braking effect of the flaps, so the thrust-spoilers were removed; instead an 11-degree afterbody was installed, which improved the specific range by 1.5%. Further improvements led to a 15-degree afterbody, enabling the L-1011 "to beat its predicted specific air range at 0.85 Mach by between 3.5 and 5.5 percent, the exact figure depending on cruise weight."<ref name=":0" />{{Rp|26–27}}

=== All-flying tail ===
Instead of the trimmable horizontal stabilizer (THS) found on most jetliners of its time, the L-1011 incorporated an all-flying tail – a [[Physics:Stabilator|stabilator]]. The aft portion had a geared (anti-servo) elevator that was linked to and moved with the stabilator, changing the stabilator's camber and improving the overall control surface effectiveness. Lockheed's main drive away from a THS was "[eliminating] mis-trim and runaway trim problems that have contributed to a number of accidents in the past."<ref name=":0" />{{Rp|30–31}}<ref>{{Cite book|last=Beach|first=J. B.|title=SAE Technical Paper Series|date=1968-02-01|chapter=Designing the Lockheed L-1011 to Meet Airline Needs Beyond 1970|volume=1|chapter-url=https://www.sae.org/publications/technical-papers/content/680545/|language=en|location=Warrendale, PA|pages=2229|doi=10.4271/680545}}</ref> The fact that the elevators are not moved directly led to the failure in recognizing the jamming (trailing edge up) of the left elevator aboard Delta Air Lines Flight 1080 in 1977.<ref>{{Cite web|last=LisbonJet|first=Publicada por|title=Delta flight 1080 incident|url=https://blog.tristar500.net/2017/08/delta-flight-1080-incident.html|access-date=2020-12-10|language=en}}</ref>

=== Fuel system ===
The L-1011-1 has four wing tanks; each inboard tank feeds the respective wing engine, and the two outboard tanks feed the tail engine via a flow equalizer.<ref name=":0" />{{Rp|33}} The additional center tank of the long-range variants, which is two halves, is located between the wing halves. Each center tank half acts as additional capacity to its adjacent inboard wing tank; filling it by way of [[Physics:Injector|ejector pumps]]. When the center tank is filled, it is used to [[Engineering:Aircraft fuel system#Multi-engine aircraft fuel system|crossfeed]] all three engines in flight (by way of the ejector pumps and crossfeed valves) until the center tank is empty and the remaining tanks are equalized.<ref>{{Cite book|url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a119572.pdf|archive-url=https://web.archive.org/web/20200321124424/https://apps.dtic.mil/dtic/tr/fulltext/u2/a119572.pdf|url-status=live|archive-date=March 21, 2020|title=Commercial Aircraft Airframe Fuel Systems Survey and Analysis|publisher=FAA Technical Center|year=1982|pages=41–44}}</ref>

=== Landing gear ===
The nose landing gear had two attachment points forward and aft, allowing a short-enough [[Engineering:Pushback (aviation)|tug]] to push or pull the plane from directly underneath, a feature to allow operations where there wasn't enough forward space at some airports, which was more common at the time.<ref name=":0" />{{Rp|34}}

=== Electrical system and Avionics ===
The L-1011 was the first jetliner to have an integrated drive generator (IDG).<ref name=":0" />{{Rp|34}}

The FMS on the L-1011, certified by the FAA in September 1977, offered many features that have since become common. The features were aimed at greatly reducing crew workload and improving [[Physics:Fuel efficiency|fuel efficiency]]. Of those are a Mach/IAS cruise control, an automatic Rough Air Mode that detects turbulence and adjusts the engine power setting accordingly, and a descent mode that figures out the optimum location to start a descent by "back computing" from a preselected point, allowing "on-altitude and on-speed" arrival.<ref name=":0" />{{Rp|36–38}}

The L-1011 also featured a highly advanced [[Engineering:Autopilot|autopilot]] system and was the first widebody to receive FAA certification for Cat-IIIc [[Engineering:Autoland|autoland]]ing, which approved the TriStar for completely blind landings performed by the aircraft's autopilot in zero-[[Earth:Visibility|visibility]] weather.<ref>{{cite news |last= Young |first= David |url= https://pqasb.pqarchiver.com/chicagotribune/access/614749782.html?dids=614749782:614749782&FMT=ABS&FMTS=ABS:AI&type=historic&date=Sep+18%2C+1977&author=&pub=Chicago+Tribune&desc=Look+Ma%2C+no+hands--learning+how+to+land+a+jumbo+jet&pqatl=google |title= Look Ma, no hands—learning how to land a jumbo jet |work= Chicago Tribune |date= September 18, 1977 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105083907/http://pqasb.pqarchiver.com/chicagotribune/access/614749782.html?dids=614749782:614749782&FMT=ABS&FMTS=ABS:AI&type=historic&date=Sep+18,+1977&author=&pub=Chicago+Tribune&desc=Look+Ma,+no+hands--learning+how+to+land+a+jumbo+jet&pqatl=google |url-status= dead }}</ref> The L-1011 used an inertial navigation system to navigate;<ref>{{cite web |url= http://www.es.northropgrumman.com/solutions/ltn92/assets/LTN-92_Ring_Laser_Gyro_Inertia.pdf |title= LTN-92 Laser Gyro INS |archive-url= https://web.archive.org/web/20110927145118/http://www.es.northropgrumman.com/solutions/ltn92/assets/LTN-92_Ring_Laser_Gyro_Inertia.pdf |archive-date= September 27, 2011 |publisher= Northrop Grumman |access-date= July 16, 2011}}</ref><ref>{{cite book |url= http://www.tristar500.net/articles/cstmp_stansted.pdf |title= Report: Lockheed L1011-500 Tristar, CS-TMP |archive-url= https://web.archive.org/web/20091222142615/http://www.tristar500.net/articles/cstmp_stansted.pdf |archive-date= December 22, 2009 |publisher= Air Accidents Investigation Branch |access-date= July 16, 2011}}</ref> this included aligning the navigation system by entering current coordinates of longitude and latitude.<ref name="ReferenceA" />

It also had a unique direct lift control (DLC) system, which allowed for smooth approaches when landing, without having to use significant pitch changes while on the approach path.<ref>{{cite report |url= http://www.aaib.gov.uk/cms_resources.cfm?file=/dft_avsafety_pdf_501051.pdf |title= Report: Lockheed L1011-385-1-14, G-BBAF |page= 5 |publisher= Air Accidents Investigation Branch |access-date= July 16, 2011}}</ref><ref>{{cite magazine |last= Kocivar |first= Ben |url= https://books.google.com/books?id=-AAAAAAAMBAJ&q=l1011&pg=PA50 |title= Giant Tri-Jets Are Coming |magazine= Popular Science |volume= 197 |issue= 6 |date= December 1970 |pages= 50–52 |issn= 0161-7370}}</ref> DLC helps maintain the aircraft on the glideslope during final approach by automatically deploying spoiler panels on the wings. Thus, rather than maintaining the descent by adjusting pitch, DLC helps control the descent while maintaining a more consistent pitch angle, using four redundant hydraulic systems. The production also used a unique "autoclave" system for bonding fuselage panels together; this made the L-1011 extremely resistant to corrosion.

=== Other components and systems ===
The APU was capable of operating up to 30,000 feet; its two square-shaped inlet doors are situated on the bottom fuselage on the aircraft's centerline towards the rear of the plane.<ref name=":0" />{{Rp|28}}

Compared to the typical three-system of its era, the L-1011 had four independent 3,000-psi hydraulic systems, A through D.<ref name=":0" />{{Rp|29}}

==Operational history==

===Commercial===
[[File:Eastern Air Lines Lockheed L-1011 Tristar 1 Proctor-1.jpg|thumb|left|An Eastern Air Lines L-1011 TriStar in St. Louis in 1972. This aircraft would become the first L-1011 and first wide-body hull-loss as Eastern Air Lines Flight 401.]]
TWA heralded the TriStar as one of the safest aircraft in the world in promotional literature in the 1980s when concern over the safety record of the [[Engineering:McDonnell Douglas DC-10|McDonnell Douglas DC-10]], flown by rival airlines, was at its peak.<ref name=David_Encyclo/> The L-1011 has been involved in five fatal accidents, only one of which was due to a problem with the aircraft.<ref>{{cite web |url= https://www.super70s.com/lockheed-l-1011/ |title= Lockheed L-1011 |work= Super70s.com |access-date= December 4, 2011}}</ref>

[[Company:Delta Air Lines|Delta Air Lines]] was the type's largest customer.<ref name="delmus">{{cite web |url= http://deltamuseum.org/M_Education_DeltaHistory_Aircraft_Lockheed_L-1011.htm |title= Delta History: Lockheed L-1011 |publisher= Delta Museum |access-date= July 16, 2011}}</ref> Delta retired its TriStars in 2001 to replace them with the Boeing 767-400ER.  Cathay Pacific eventually became the largest non-U.S. operator of the type by acquiring many of the Eastern Air Lines examples when Eastern went bankrupt, operating as many as 21 aircraft.  Cathay Pacific retired its L-1011s in October 1996 and replaced the type with the [[Engineering:Airbus A330|Airbus A330-300]]. TWA withdrew its last TriStar from service in 1997.

[[File:Cathay Pacific L-1011 at Osaka Airport.jpg|thumb|A Cathay Pacific L-1011 at Osaka International Airport, Japan in 1990]]
To secure the Japanese market, Lockheed secretly bribed several members of the Japanese government to subsidize All Nippon Airways' purchase of L-1011s; this caused a significant scandal when the bribes were uncovered.<ref>{{cite news |last= Nevin |first= Loouis |url= https://news.google.com/newspapers?id=pEMVAAAAIBAJ&pg=4356,2474197&dq=lockheed+japan&hl=en |title= Payoff scandal could prove costly to Lockheed; Japanese might halt orders |work= The Bulletin |date= February 27, 1976}}</ref><ref>{{cite news |url= https://www.nytimes.com/1976/04/03/archives/lockheeds-japanese-data-asked-in-senate-subpoena.html |title= Lockheed's Japanese data asked in Senate subpoena |work= The New York Times |date= April 3, 1976 |access-date= July 16, 2011}}</ref> The discovered scale to what has become known as the Lockheed bribery scandal led to the arrest of Japanese Prime Minister Kakuei Tanaka, as well as several other officials.<ref>{{cite news |last= Kamm |first= Henry |url= https://select.nytimes.com/gst/abstract.html?res=F10A1EFC3E5D167493C6AB178AD85F438785F9 |title= Lockheed Scandal in Japan headed for its trial phase |work= The New York Times |date= January 24, 1977}}</ref> Within Lockheed, board chairman Daniel Haughton and vice chairman and president Carl Kotchian resigned their posts on February 13, 1976.<ref>{{cite news |last= Lindsey |first= Robert |url= https://www.nytimes.com/1977/07/03/archives/kotchian-calls-himself-the-scapegoat-kotchian-calls-himself-the.html |title= Kotchian calls himself the Scapegoat |work= The New York Times |date= July 3, 1977}}</ref> Tanaka was eventually tried and found guilty of violating foreign exchange control laws but was not charged with bribery, a more serious criminal offense.<ref>{{cite magazine |url= http://www.time.com/time/magazine/article/0,9171,914484,00.html |archive-url= https://web.archive.org/web/20070823184822/http://www.time.com/time/magazine/article/0,9171,914484,00.html |url-status= dead |archive-date= August 23, 2007 |title= Bribery Shokku At the Top |magazine= Time |date= August 9, 1976 |access-date= July 16, 2011}}</ref><ref>{{cite book |last1= Hunziker |first1= Steven |first2= Ikuru |last2= Kamimura |chapter-url= http://www.rcrinc.com/tanaka/ch4-3.html |chapter= The Lockheed Scandal |title= Kakuei Tanaka: A Political Biography Of Modern Japan |access-date= July 16, 2011 |archive-date= September 27, 2011 |archive-url= https://web.archive.org/web/20110927042639/http://www.rcrinc.com/tanaka/ch4-3.html |url-status= dead }}</ref> Crucially for Lockheed, the fallout from the scandal included the loss of a contract worth over $1 billion.<ref>{{cite news |url= https://news.google.com/newspapers?id=Pb0MAAAAIBAJ&pg=6590,1059160&dq=lockheed+japan&hl=en |title= Lockheed loses big Japanese contract |work= St. Petersburg Times |date= February 11, 1976 }}{{Dead link|date=June 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The [[Place:Soviet Union|Soviet Union]] at that time lacked a widebody airliner. Development of its own [[Engineering:Ilyushin Il-86|Ilyushin Il-86]] was delayed;<ref>{{cite web |url= http://edition.cnn.com/2002/WORLD/europe/07/28/aircrash.ilyushin/index.html |title= Facts: The Ilyushin Il-86 |publisher= CNN |date= July 28, 2002 |access-date= July 16, 2011}}</ref><ref>{{cite news |url= https://pqasb.pqarchiver.com/latimes/access/658660432.html?dids=658660432:658660432&FMT=CITE&FMTS=CITE:AI&type=historic&date=Jul+04%2C+1981&author=&pub=Los+Angeles+Times&desc=Soviet+Wide-Bodied+Jet+Begins+Regular+Service+to+East+Berlin&pqatl=google |title= Soviet Wide-Bodied Jet begins regular service to East Berlin |work= Los Angeles Times |date= July 4, 1981 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105083935/http://pqasb.pqarchiver.com/latimes/access/658660432.html?dids=658660432:658660432&FMT=CITE&FMTS=CITE:AI&type=historic&date=Jul+04,+1981&author=&pub=Los+Angeles+Times&desc=Soviet+Wide-Bodied+Jet+Begins+Regular+Service+to+East+Berlin&pqatl=google |url-status= dead }}</ref> consequently, in the mid-1970s, the Soviets started negotiations to buy 30 TriStars and license-produce up to 100 a year.<ref>{{cite book |last= Birtles |first= Philip |title= Lockheed TriStar |series= Modern Civil Aircraft No 8 |location= London |publisher= Ian Allan |year= 1989 |isbn= 978-1-85310-934-8}}</ref><ref>{{cite news |url= https://pqasb.pqarchiver.com/latimes/access/643359962.html?dids=643359962:643359962&FMT=CITE&FMTS=CITE:AI&type=historic&date=Nov+01%2C+1973&author=&pub=Los+Angeles+Times&desc=World&pqatl=google |title= A British paper said Russia may buy the jet engine used in the Tristar |work= Los Angeles Times |date= November 1, 1973 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105083948/http://pqasb.pqarchiver.com/latimes/access/643359962.html?dids=643359962:643359962&FMT=CITE&FMTS=CITE:AI&type=historic&date=Nov+01,+1973&author=&pub=Los+Angeles+Times&desc=World&pqatl=google |url-status= dead }}</ref> The talks collapsed as US President [[Biography:Jimmy Carter|Jimmy Carter]] made human rights an important consideration in US foreign policy.<ref>{{cite news |last= Neikirk |first= Bill |url= https://pqasb.pqarchiver.com/chicagotribune/access/615547772.html?dids=615547772:615547772&FMT=ABS&FMTS=ABS:AI&type=historic&date=Mar+27%2C+1977&author=&pub=Chicago+Tribune&desc=World+hears+Carter+human+rights+call&pqatl=google |title= World hears Carter human rights call |work= Chicago Tribune |date= March 27, 1977 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105084003/http://pqasb.pqarchiver.com/chicagotribune/access/615547772.html?dids=615547772:615547772&FMT=ABS&FMTS=ABS:AI&type=historic&date=Mar+27,+1977&author=&pub=Chicago+Tribune&desc=World+hears+Carter+human+rights+call&pqatl=google |url-status= dead }}</ref><ref>{{cite news |last= Jacoby |first= Tamar |url= http://findarticles.com/p/articles/mi_m1316/is_v18/ai_4262005/ |archive-url= https://archive.today/20120527061706/http://findarticles.com/p/articles/mi_m1316/is_v18/ai_4262005/ |url-status= dead |archive-date= 2012-05-27 |title= Did Carter fail on human rights? |work= Washington Monthly |date= June 1986}}</ref> The TriStar was also listed by the Coordinating Committee as embodying advanced technology forbidden for sale to potential enemies, which presented a serious obstacle to the export deal.

The last three airlines to operate the L-1011 in ''scheduled'' service were Brussels Airlines (codeshare with Hewa Bora Airways), Thai Sky Airlines, and Lloyd Aereo Boliviano, with final flights in August 2007, February 2008, and May 2008, respectively.<ref>{{Cite web|title=Routes Trivia: Where Did All The TriStars Go?|url=https://www.routesonline.com/news/29/breaking-news/149211/routes-trivia-where-did-all-the-tristars-go/|access-date=2020-12-10|website=Routesonline|language=en-GB}}</ref> In later years the L-1011 has been used by smaller start-up carriers, particularly in Africa and Asia. These operators mainly do their business in the ''ad hoc'' [[Finance:Air charter|charter]] and wet leasing businesses. [[Company:ATA Airlines|ATA Airlines]] (formerly known as American Trans Air) fleet included over 19 TriStars, but operations dwindled to only three L-1011-500s before the company's shutdown in April 2008.

===Military===
{{Main|Engineering:Lockheed TriStar (RAF)}}

The TriStar has also been used as a military tanker and passenger/cargo aircraft. The British {{wipe|Royal Air Force}} had nine aircraft of four variants. The aircraft were six ex-British Airways and three Pan Am L-1011-500s.<ref name="Frawley Military">{{cite book |last= Frawley |first= Gerard |title= The International Directory of Military Aircraft, 2002–2003 |location= Fyshwick, ACT, Australia |publisher= Aerospace Publications |year= 2002 |isbn= 1-875671-55-2 |page= 44}}</ref><ref name= "BAfleerenew">{{cite news |last= Prokesch |first= Steven |url= https://www.nytimes.com/1990/07/07/business/british-air-purchasing-boeing-747-s.html |title= British Air Purchasing Boeing 747s |work= The New York Times |date= July 7, 1990}}</ref><ref>{{cite magazine |title= TriStar Tankers...The RAF Goes Widebody |magazine= Air International |volume= 29 |issue= 6 |date= December 1985 |pages= 271–277 |location= Bromley, UK |publisher= Fine Scroll}}</ref> All of the aircraft served with No. 216 Squadron, and were based at RAF Brize Norton. The TriStar was replaced in RAF service by the [[Engineering:Airbus A330 MRTT|Airbus A330 MRTT]] under the Future Strategic Tanker Aircraft <!-- (FSTA) --> program.<ref>{{Cite news|url=https://www.flightglobal.com/news/articles/uk-signs-13-billion-tanker-deal-222521/|title=UK signs £13 billion tanker deal|last=Craig|first=Hoyle|date=March 27, 2008|work=FlightGlobal|language=en-GB}}</ref> 216 Squadron was officially disbanded on March 20, 2014, and flew its last sorties with the TriStar on March 24, 2014.<ref>{{cite web |last= Hoyle |first= Craig |url= http://www.flightglobal.com/news/articles/RAF-TriStars-to-fly-final-sortie-397316/ |title= RAF TriStars to fly final sortie |work =Flight International |date= March 24, 2014 |access-date= March 25, 2014}}</ref>

===Other===
[[File:Vandenberg supports successful Pegasus launch (6696118).jpg|thumb|[[Company:Northrop Grumman|Northrop Grumman's]] L-1011-100 "Stargazer" mounting Pegasus rocket]]

In the early 1990s, Orbital Sciences began to use a converted L-1011-100 named ''[[Engineering:Stargazer (aircraft)|Stargazer]]'' to launch [[Engineering:Pegasus (rocket)|Pegasus]] rockets into orbit around Earth. This venture effectively rendered the small Scout rocket obsolete.<ref>{{cite web |url= http://www.orbital.com/SpaceLaunch/Pegasus/ |title= Tristar used to launch Pegasus |work= Orbital.com |access-date= July 16, 2011}}</ref><ref>{{cite web |url= http://www.air-and-space.com/20020201%20VAFB%20HESSI.htm |title= Orbital Sciences Corporation L-1011, Stargazer carries HESSI spacecraft from Vandenberg AFB to the Kennedy Space Center |work= Air and Space |date= February 1, 2002}}</ref> This aircraft was also used in support of the X-34 and [[Engineering:NASA X-43|X-43]] programs. [[Organization:NASA|NASA]] performed aerodynamic research on Orbital Sciences' L-1011 in 1995.<ref>{{cite web |url= http://www.dfrc.nasa.gov/Gallery/Photo/L-1011/index.html#APO |archive-url= https://web.archive.org/web/19970605021301/http://www.dfrc.nasa.gov/gallery/photo/L-1011/index.html#APO |url-status= dead |archive-date= June 5, 1997 |title= Dryden L-1011 Tristar |work= NASA Photo Collection |publisher= National Aeronautics and Space Administration |date= July 16, 2011}}</ref> In 2014, three L-1011s in the world were airworthy.<ref>{{cite news |last= Howarth |first= Nigel |url= http://aviationweek.com/blog/contrasting-fortunes-old-freighters-california-desert |title= Contrasting fortunes for old freighters in the California desert |work= Aviation Week & Space Technology |date= April 15, 2014 |access-date= May 24, 2014 |archive-url= https://web.archive.org/web/20140524220548/http://aviationweek.com/blog/contrasting-fortunes-old-freighters-california-desert |archive-date= May 24, 2014}}</ref> As of 2019, ''Stargazer'' is the only active L-1011.<ref>{{Cite web|url=https://spaceflightnow.com/2019/10/10/rockets-purchased-by-stratolaunch-back-under-northrop-grumman-control/|title=Rockets purchased by Stratolaunch back under Northrop Grumman control |website= Spaceflight Now |first=Stephen|last=Clark}}</ref>

==Variants==

The earlier versions of the L-1011, such as the -1, -100, and -150 can be distinguished from the later models by the design of the middle engine nacelles. The earlier version nacelle has a round intake, whereas the later models have a small vertical fin between the bottom of the middle engine intake and the top of the fuselage.

The two L-1011 aircraft delivered to Pacific Southwest Airlines were configured with internal [[Engineering:Airstair|airstair]] doors that led into an entry hall in what was normally the forward lower baggage hold. This was to allow operations from airfields that did not have terminal buildings with jet bridges. These two aircraft were later in service with Aeroperú and Worldways Canada.

===L-1011-1===
[[File:Thai Sky Airlines L-1011-1 HS-AXA HKG 2005-3-20.png|thumb|A Thai Sky Airlines L-1011-1 at Hong Kong International Airport in 2005]]

The L-1011-1 (FAA certification L-1011-385-1) was the first production model of the L-1011, designed for short- and medium-range flights. This variant served as the basis for subsequent variants. This type was purchased by Air Canada, ANA, Cathay Pacific, Eastern, and other operators with regional trunk routes requiring a widebody aircraft. Pacific Southwest Airlines purchased two L-1011-1 models with lower deck seating.<ref>{{cite web |url= http://www.usairways.com/en-US/aboutus/pressroom/history/psa.html |title= US Airways History |publisher =US Airways |access-date= July 16, 2011}}</ref> This variant was also one of the few widebodies to have the option for a full-height built-in [[Engineering:Airstair|airstair]].<ref name=David_Encyclo/>

The L-1011-1 was first delivered to Eastern Air Lines on April 5, 1972. A total of 160 L-1011-1 TriStars were built before production ended in 1983, although the majority of these, 119 or 75% of the total, were completed during a four-year period from 1972 to 1975. Most sales of the L-1011-1 were to US operators, with just three airlines, Delta, Eastern, and TWA, taking delivery of 110 combined. A further two aircraft were placed with a fourth US airline, Pacific Southwest Airlines.<ref name=David_Encyclo/>

===L-1011-100===
[[File:Trans World Airlines Lockheed L-1011-385-1-15 TriStar 100 Marmet.jpg|thumb|Trans World Airlines L-1011-100 TriStar]]

The L-1011-100 (FAA certification L-1011-385-1-14) was the second production model of the L-1011 and first flew in 1975 and featured a new center fuel tank and higher gross weights that increased the aircraft's range by nearly {{convert|930|mi|km}}. Launch orders for the L-1011-100 were placed by Saudia and Cathay Pacific, for two each, in May 1974. Deliveries began in June 1975.

The variant was also purchased by several airlines with longer-range routes, such as TWA, Air Canada, and BEA (which merged with BOAC to form British Airways). The first two L-1011-100s (serial numbers 1110 and 1116) were delivered new to Saudia with the same fuel capacity as the L-1011-1 (FAA certification L-1011-385-1-14); these were later upgraded to L-1011-200 specification.

===L-1011-50===
The L-1011-50 was an upgraded version of the L-1011-1 with an increase in maximum takeoff weight from {{convert|430,000|lb|kg|sigfig=3}} to either {{convert|440,000|lb|kg|sigfig=3}} or {{convert|450,000|lb|kg|sigfig=3}}. Fuel capacity was not increased. The -50 was available only as a conversion package for the L-1011-1 and was never built new.

===L-1011-150===
The L-1011-150 was a development of the L-1011-1 with its maximum takeoff weight increased to {{convert|470000|lb|kg}}. It was available only as a conversion for the L-1011-1. The -150 involves the conversion of Group 1 and Group 2 L-1011-1 aircraft to an MTOW of {{convert|470000|lb|kg}}, an increase of {{convert|40000|lb|kg}}, about 10%, from the L-1011-1, giving the aircraft a slightly better range than the -50, but without the additional center-section fuel tank, less than the L-1011-100 aircraft.  The first aircraft was converted by MBB at Lemwerder in Germany during the winter of 1988–89 and was subsequently handed over to Air Transat of Canada on May 11, 1989.

===L-1011-200===
[[File:Saudi Arabian Airlines L-1011-200 HZ-AHE LHR 1985-5-17.png|thumb|A Saudia L-1011-200 TriStar at London Heathrow Airport, 1985]]

The L-1011-200 (FAA certification L-1011-385-1-15), the third production model of the L-1011, was introduced in 1976. Although otherwise similar to the -100, the -200 uses Rolls-Royce RB.211-524B engines to improve its performance in hot and high-altitude conditions. Gulf Air used -200 models to replace its earlier-generation [[Engineering:Vickers VC10|Vickers VC10]] fleet.

Other than the engines, the basic TriStar -200 is identical to the -100, with center-section fuel, having a MTOW of {{convert|466000|lb|kg}}, and fuel capacity of {{convert|26400|usgal|L}} as the -100. An increase of gross weight to {{convert|474000|lb|kg}} is possible, with the heavier aircraft offered by Lockheed as -200I or -200(Improved).  Saudi Arabian Airlines (Saudia) was a launch customer for the -200 series and operated a sizable fleet until 1998. A total of 24 L-1011-200 aircraft were built new, with the first delivered to Saudia on May 28, 1977. Like other TriStar improvements, a conversion program has also been offered.

===L-1011-250===
[[File:Lockheed L-1011-250 Tristar, Delta Air Lines JP6032824.jpg|thumb|left|A Delta Air Lines L-1011-250 at Frankfurt Airport, 1994]]

The L-1011-250 was an upgrade developed for late-model L-1011-1 aircraft and all L-1011-100 and L-1011-200 aircraft. The more powerful engines, lengthened wing, active-load-control ailerons and other systems that had been developed for the L-1011-500 were adapted into the baseline model.  The changes resulted in increases in maximum takeoff weight to {{convert|510000|lb|kg}} and fuel capacity from 23,600&nbsp;US gal (89,335&nbsp;L) to 31,632&nbsp;US gal (119,735&nbsp;L). This variant also used the upgraded [[Engineering:Rolls-Royce RB211|RB211-524B4I]] engine, which could be easily retrofitted to the existing [[Engineering:Rolls-Royce RB211|RB211-524B]] powerplants of the L-1011-200, but it required a re-engining on the L-1011-1 and L-1011-100, which used the original RB211-22B. The conversion allowed the L-1011 to match the performance of the long-range McDonnell Douglas DC-10-30. Although it could be applied to all L-1011 models, the upgrade was only undertaken by Delta on six late-model L-1011-1 aircraft.

===L-1011-500===
[[File:TAP Air Portugal L-1011-500 CS-TEF LIS 1988-6-30.png|thumb|A TAP Air Portugal L-1011-500 departing from Lisbon Airport in 1988]]

The L-1011-500 (FAA certification L-1011-385-3) was the last L-1011 variant to enter production. It was a longer-range variant first flight-tested in 1978. Its fuselage length was shortened by {{convert|14|ft|m}} and MTOW increased to allow higher fuel loads.{{citation needed|date=October 2013}} More powerful RB.211-524 engines, increased wingspan, active-load-control ailerons and other improved systems were features introduced by Lockheed to exploit newly available technologies in the late 1970s. The -500 variant was popular among international operators and formed a significant portion of the L-1011 fleet of Delta and British Airways. However, it entered service seven years after the similar [[Engineering:McDonnell Douglas DC-10#Longer-range variants|DC-10-30]] entered service.

The TriStar 500 first flew on October 16, 1978, with the first delivery to British Airways on April 27, 1979. It entered service with British Airways on May 7, 1979, flying between London and Abu Dhabi. The last L-1011 produced was a TriStar 500, operated by the Las Vegas Sands.<ref>{{Cite web|url=https://www.airfleets.net/listing/l10-5.htm|title = Lockheed L-1011 TriStar Production list &#124; Airfleets aviation}}</ref>

====Dimensions====
The TriStar 500 has an overall length of {{convert|164|ft|2|in|m|2}} and wingspan increased to {{convert|164|ft|4|in|m|2}} (early TriStar versions originally had the TriStar 1 wing with a span of {{convert|155|ft|4|in|m|2}}).

====Flying surfaces====
Lockheed developed some aerodynamic improvements for the TriStar 500 which included a modified wing-to-body fairing, a fillet below the central intake, extended wingtips, and "active ailerons" or active control system (ACS). The new fairing reduced drag, while the fillet reduced noise in the rear cabin. The wingtip extensions increased aspect ratio, thus reducing induced drag, but resulted in increased bending. The ACS developed to solve this, provided gust alleviation, improving ride during flight, reduced fuel burn, and increased fatigue life.

Earlier TriStar 500s were delivered with the standard wing; these were later retrofitted with ailerons and extended wingtips. Pan Am was the first customer to order the -500 with the extended wingtips and active ailerons. Aircraft serial number 1176, the first for Pan Am, was the first TriStar 500 to be fitted with them as standard.

====Powerplant====
[[File:Lockheed L-1011-385-3 TriStar 500, AirLanka AN0962210.jpg|thumb|An Air Lanka L-1011-500 TriStar ferrying an extra engine.]]
The TriStar 500 is equipped with the more powerful RB211-524B engines. Initially rated at {{convert|50000|lbf|kN|abbr=on}} thrust each, the higher-thrust {{convert|53000|lbf|kN|abbr=on}} -524B4 Improved (also referred to as the -524B4I) later became available, which also offered improved [[Physics:Fuel efficiency|fuel efficiency]].

====Performance====
Originally certified with an MTOW of {{convert|496000|lb|kg}}, an increased MTOW of {{convert|504000|lb|kg}} was later certified in 1979, and all earlier production aircraft were certified at this weight. A further increase, to {{convert|510000|lb|kg}}, is also available, and most TriStar 500s are thought to have had this increase. Standard fuel capacity is {{convert|31600|USgal|L}}, giving the TriStar 500 a range of about {{convert|5200|nmi|km}} with 246 passengers and baggage.

====Cabin====
The TriStar 500's maximum passenger capacity is 315, although no aircraft were operated with that number of seats.  A typical two-class layout might include 21 First Class and 229 Economy Class for a maximum of 250 passengers. More spacious three-class layouts used on longer routes include 233 with 12 First Class, 32 Business Class, and 189 Economy Class with Delta Air Lines.  The aircraft is equipped with six exits, two fewer than the long-body TriStars, thus reducing the exit limit maximum.

==Operators==

One of the two L-1011 TriStars in service as of 2022 is the ''[[Engineering:Stargazer (aircraft)|Stargazer]]'' air-launch mothership, operated by [[Company:Northrop Grumman#Space Systems|Northrop Grumman Space Systems]].<ref>{{cite web |url= http://www.orbital.com/LaunchSystems/SpaceLaunchVehicles/Pegasus/L-1011/ |title= Pegasus/L-1011 |work= Orbital ATK |year= 2015 |access-date= March 28, 2015}}</ref><ref>{{cite web |last= Clark |first= Stephen |url= http://www.spaceflightnow.com/pegasus/nustar/120403june/ |title= Pegasus Launch Report: Launch of NASA X-ray telescope targeted for June |work= Spaceflight Now |date= April 3, 2012 |access-date= March 28, 2015}}</ref><ref>{{cite web |last= Clark |first= Stephen |url= https://spaceflightnow.com/2019/10/10/rockets-purchased-by-stratolaunch-back-under-northrop-grumman-control/ |title= Rockets purchased by Stratolaunch back under Northrop Grumman control |work= Spaceflight Now |date= October 10, 2019 |access-date= October 15, 2019}}</ref>
<!-- 
In Kansas City, MO the [https://www.tristarexperience.org/] Tristar Experience operates N910TE, a former PSA jet, and has once again made it airworthy. The group is modifying the plane for use as a mobile educational tool for STEM students. -->

==Accidents and incidents==
[[File:Saudia 163 close-up.jpg|thumb|right|The burnt out fuselage of the TriStar involved in Saudia Flight 163. After carrying out an emergency landing at Riyadh International Airport due to an in-flight cargo fire, a failure by the crew to carry out the emergency evacuation procedures led to all 301 people on board perishing from the flames and smoke.]]

As of December 2011, the L-1011 has been involved in 35 [[Engineering:Aviation accidents and incidents|aviation occurrences]],<ref>{{cite web |url= http://aviation-safety.net/database/dblist.php?Type=336 |title= Lockheed L-1011 Tristar incidents |work= Aviation-Safety.net |date= July 9, 2020 |access-date= July 11, 2020}}</ref> including 10 [[Engineering:Aviation accidents and incidents|hull-losses]],<ref>{{cite web |url= http://aviation-safety.net/database/dblist.php?field=typecode&var=336%&cat=%1&sorteer=datekey&page=1 |title= Lockheed L-1011 Tristar hull-losses |work= Aviation-Safety.net |date= July 9, 2020 |access-date= July 11, 2020}}</ref> with 540 fatalities.<ref>{{cite web |url= http://aviation-safety.net/database/type/type-stat.php?type=336 |title= Lockheed L-1011 Tristar Statistics |work= Aviation-Safety.net |date= July 9, 2020 |access-date= July 11, 2020}}</ref> Of the four pioneering widebody aircraft ([[Engineering:Boeing 747|Boeing 747]], [[Engineering:McDonnell Douglas DC-10|McDonnell Douglas DC-10]], L-1011, and [[Engineering:Airbus A300|Airbus A300]]/[[Engineering:Airbus A310|A310]] family), the Lockheed L-1011 had comparatively few accidents and a better safety record than its competitors.<ref>{{cite web |url= http://www.lockheedclassics.com/Civil.html#tristar |title= 1970: Lockheed L-1011 Tristar |archive-url= https://web.archive.org/web/20120428054811/http://www.lockheedclassics.com/Civil.html |archive-date=April 28, 2012 |work= LockheedClassics.com |access-date= August 25, 2012}}</ref><ref>{{cite web |url= http://www.century-of-flight.net/Aviation%20history/coming%20of%20age/Lockheed%20L.1011%20Tristar.htm |title= Lockheed L.1011 Tristar |work= Century of Flight |access-date= August 25, 2012 |archive-date= April 26, 2013 |archive-url= https://web.archive.org/web/20130426042644/http://www.century-of-flight.net/Aviation%20history/coming%20of%20age/Lockheed%20L.1011%20Tristar.htm |url-status= dead }}</ref><ref>{{cite book |last= Birtles |first= Phillip |title= Lockheed L-1011 TriStar |series= Airliner Color History |location= St. Paul, Minnesota |publisher= Motorbooks International |year= 1998 |isbn= 978-0-7603-0582-9 |page= 111}}</ref>
* On December 29, 1972, Eastern Air Lines Flight 401, an L-1011, crashed in the Florida Everglades as a result of the flight crew's failure to monitor the flight instruments during a malfunction of the landing gear position indicator system. The crash resulted in 101 fatalities, and was the subject of two TV movies, ''Crash'' and ''The Ghost of Flight 401''. It was also the subject of a ''Mayday'' episode.<ref>{{cite book |last= Job |first= Macarthur |chapter= Chapter 12: Hey{{Snd}} what's happening here? |title= Air Disaster |volume= 1 |location= Fyshwick, ACT, Australia |publisher= Aerospace Publications |year= 1994 |isbn= 1-875671-11-0 |pages= 99, 101–102}}</ref><ref>{{cite news |url= https://www.nbcnews.com/id/22394676 |title= 35 years after jetliner crash, hero gets his due |agency= Associated Press |publisher= NBC News |date= December 25, 2007}}</ref>
* On April 12, 1977, Delta Air Lines Flight 1080, on takeoff from San Diego, had a left stabilizer jammed undetected in the full trailing-edge-up position.<ref name="The Saving Of Flight 1080">{{cite news |title=The Saving Of Flight 1080 |url=https://www.washingtonpost.com/archive/opinions/1978/10/08/the-saving-of-flight-1080/bc18f021-691d-4b19-8041-dc03a089bf6d/ |newspaper=Washington Post|date=October 8, 1978}}</ref> This failure resulted in a large noseup and rolling moment that almost exceeded the capability of the flight controls.<ref>{{cite book |title= Development and Flight Evaluation of an Emergency Digital Flight Control System Using Only Engine Thrust on an F-15 Airplane |id= NASA TP-3627 |date= September 1996 |last1= Burcham | first1= Frank W. Jr. |first2= Trindel A. |last2= Maine |first3= C. Gordon |last3= Fullerton |first4= Lannie Dean |last4= Webb |name-list-style= amp |url= https://www.nasa.gov/centers/dryden/pdf/88414main_H-2048.pdf |publisher= National Aeronautics and Space Administration}}</ref> The airplane was just about to stall in the clouds when Captain Jack McMahan,<ref>http://www.aahs-online.org/journals/journal_template.php?vol_no=v50n4#Article {{Webarchive|url=https://web.archive.org/web/20151118152917/http://www.aahs-online.org/journals/journal_template.php?vol_no=v50n4#Article |date=November 18, 2015 }} 4</ref> with unusual insight, reduced power on the wing engines and began using the throttles to supplement the remaining flight controls, using differential and collective engine thrust.<ref>{{harvp|Burcham|Maine|Fullerton|Webb|1996|p=11|ps=.}}</ref> Cabin crew moved all the passengers forward in the cabin to redistribute weight and help get the nose down. Steve Heidt, the flight engineer, said, "It probably didn't help much, but in that situation, we figured every little bit would help."<ref name="The Saving Of Flight 1080"/> All the way from San Diego to Los Angeles, the aircraft flew with its pitch controlled by differential thrust between tail and wing engines, while the left roll tendency was compensated by wing differential thrust, and made a successful emergency landing in Los Angeles.<ref>{{cite magazine |magazine= Annual Reviews in Control |volume= 23 |year= 1999 |pages= 91–108 |title= From Sioux City to the X-331 |first1= Edmond A. |last1= Jonckheere |first2= Poonsuk |last2= Lohsoonthorn |first3= Stephan K. |last3= Bohacek |name-list-style= amp |url= https://www.eecis.udel.edu/~bohacek/Papers/SiouxCity.pdf}}</ref> According to an incident analysis by Warren VanderBurgh, comprehensive crew training played a critical role in control recovery.<ref>{{Cite web|url=https://www.youtube.com/watch?v=WfNBmZy1Yuc| archive-url=https://ghostarchive.org/varchive/youtube/20211211/WfNBmZy1Yuc| archive-date=2021-12-11 | url-status=live|title=Control Malfunctions & Flight Instrument Anomalies|via=YouTube}}{{cbignore}}</ref>
* On August 19, 1980, a fire destroyed the L-1011-200 used for Saudia Flight 163 on the ground after the pilots made an emergency landing at [[Place:Riyadh|Riyadh]]'s International Airport due to fire in the rear of the aircraft. Delays in initiating the evacuation of the aircraft led to the deaths of all 287 passengers and 14 crew.<ref>{{cite news |url= https://news.google.com/newspapers?id=1GoaAAAAIBAJ&pg=6732,5145601&dq=l-1011+crash&hl=en |title= 265 on Saudi jet die in fiery landing |work= Milwaukee Journal |date= August 20, 1980 }}{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{cite news |url= https://news.google.com/newspapers?id=BNURAAAAIBAJ&pg=5568,2235593&dq=l-1011+crash&hl=en |title= 260 feared dead as burning jet's doors jam shut |work= Spokesman-Review |date= August 20, 1980 }}{{Dead link|date=June 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* On December 23, 1980, Saudia Flight 162, an L-1011, had a tire explode and penetrate the passenger cabin whilst in flight. The aircraft lost cabin pressure and two passengers were ejected through a hole in the cabin floor. The aircraft was later repaired and returned to service.<ref>{{cite news |url= https://pqasb.pqarchiver.com/latimes/access/682708612.html?dids=682708612:682708612&FMT=CITE&FMTS=CITE:AI&type=historic&date=Dec+24%2C+1980&author=&pub=Los+Angeles+Times&desc=2+Children+Die+in+Freak+Mishap+Aboard+Saudi+Arabian+Jetliner&pqatl=google |title= 2 Children die in freak mishap aboard Saudi Arabian jetliner |work= Los Angeles Times |date= December 24, 1980 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105084027/http://pqasb.pqarchiver.com/latimes/access/682708612.html?dids=682708612:682708612&FMT=CITE&FMTS=CITE:AI&type=historic&date=Dec+24,+1980&author=&pub=Los+Angeles+Times&desc=2+Children+Die+in+Freak+Mishap+Aboard+Saudi+Arabian+Jetliner&pqatl=google |url-status= dead }}</ref>
* On September 22, 1981, Eastern Air Lines Flight 935 departed Newark, New Jersey, and suffered an uncontained failure of its number two (tail) engine at {{convert|14500|ft|m}}, while en route to [[Place:San Juan, Puerto Rico|San Juan, Puerto Rico]].<ref>{{cite web |url= http://aviation-safety.net/database/record.php?id=19810922-0 |title= ASN Aircraft accident: Eastern Airlines L-1011, September 22, 1981 |work= Aviation-Safety.net |access-date= July 16, 2011}}</ref><ref>{{cite web |url= https://www.ntsb.gov/aviationquery/brief.aspx?ev_id=27857&key=0 |title= NTSB Identification: DCA81AA027 |publisher= National Transportation Safety Board |access-date= December 19, 2011}}</ref> The fragments from that engine damaged three of its four hydraulic systems resulting in fluid loss in them. The rudder pedals also jammed. The fragments struck but did not puncture the lines for the other hydraulic system; the captain was able to safely land the aircraft at John F. Kennedy International Airport, with some limited use of the outboard spoilers, the inboard ailerons and the horizontal stabilizer, plus differential engine power of the remaining two engines. There were no injuries. The L-1011 having four hydraulic systems (instead of three like the DC-10) allowed for a safe landing.<ref>{{cite news |url= https://pqasb.pqarchiver.com/chicagotribune/access/627204412.html?dids=627204412:627204412&FMT=ABS&FMTS=ABS:AI&type=historic&date=Nov+28%2C+1981&author=&pub=Chicago+Tribune&desc=More+DC-10+troubles+hinted&pqatl=google |title= More DC-10 troubles hinted |work= Chicago Tribune |date= November 28, 1981 |access-date= July 6, 2017 |archive-date= November 5, 2012 |archive-url= https://web.archive.org/web/20121105084038/http://pqasb.pqarchiver.com/chicagotribune/access/627204412.html?dids=627204412:627204412&FMT=ABS&FMTS=ABS:AI&type=historic&date=Nov+28,+1981&author=&pub=Chicago+Tribune&desc=More+DC-10+troubles+hinted&pqatl=google |url-status= dead }}</ref><ref>{{cite news |url= https://news.google.com/newspapers?id=NU8aAAAAIBAJ&pg=3230,5023477&dq=l-1011+crash&hl=en |title= Engines of jumbo jets have troubled history |work= Milwaukee Journal |date= November 28, 1981 }}{{Dead link|date=June 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
* On May 5, 1983, Eastern Air Lines Flight 855, L-1011 registration N334EA, while flying from Miami to Nassau, shut down the number 2 engine due to low oil pressure and began a return to Miami. Both of the remaining engines later failed. Without power, flight 855 descended from 13,000 to {{convert|4000|ft|m}} before the number 2 engine was restarted and the aircraft landed in Miami without injuries. Incorrect engine maintenance had led to the loss of oil on all three engines.<ref>{{cite web |last= Thompson |first= Steven |url= http://flytristar.tripod.com/article/art10.html |title= The Story of Eastern Flight 855 |work= FlyTristar |access-date= July 16, 2011}}</ref>
* On April 5, 1984, a Saudia Lockheed L-1011 TriStar on final approach to [[Place:Damascus|Damascus]] from Jeddah was hijacked by a Syrian national. The hijacker demanded to be taken to Istanbul, [[Place:Turkey|Turkey]], but changed his mind and requested to go to [[Place:Stockholm|Stockholm]]. After landing in Istanbul to refuel, the pilot pushed the hijacker out the emergency exit whereupon he was arrested.<ref>{{ASN accident|id=19840405-1|type=Hijacking}}</ref>
[[File:Tristar Incident LBA.jpg|thumb|A British Airtours TriStar overran the runway at Leeds Bradford International Airport in 1985.]]
* On May 27, 1985, British Airtours Flight 101, registration G-BBAI, from Palma Airport, Mallorca, Spain overran the runway on landing at Leeds Bradford International Airport, West Yorkshire, United Kingdom. 12 of the 412 people on board suffered minor injuries when exiting down steep rear ramps. The aircraft was severely damaged.<ref name=AAIB287>{{cite web |url=https://assets.publishing.service.gov.uk/media/5422fd9ae5274a13140008e5/2-1987_G-BBAI.pdf |title=Report on the Accident to Lockheed Tristar G-BBAI at Leeds Bradford Airport on 27 May 1985 |publisher=Accidents Investigation Branch |access-date=July 17, 2017}}</ref>
* On August 2, 1985, Delta Air Lines Flight 191, an L-1011, crashed while approaching Dallas/Fort Worth International Airport in [[Earth:Microburst|microburst]] conditions. The crash killed eight of 11 crew members and 128 of the 152 passengers on board, as well as one person on the ground.<ref>{{cite book |url= http://www.airdisaster.com/reports/ntsb/AAR86-05.pdf |title= Delta Air Lines Flight 191 Crash |archive-url= https://web.archive.org/web/20140817111801/http://www.airdisaster.com/reports/ntsb/AAR86-05.pdf |archive-date= August 17, 2014 |publisher= National Transportation Safety Board |url-status= usurped |access-date= August 25, 2012}}</ref><ref name=time>{{cite magazine |last= Magnuson |first= Ed |url= http://www.time.com/time/magazine/article/0,9171,1050423-2,00.html |archive-url= https://web.archive.org/web/20080119100349/http://www.time.com/time/magazine/article/0,9171,1050423-2,00.html |url-status= dead |archive-date= January 19, 2008 |title= Like a Wall of Napalm |magazine= Time |date =April 18, 2005}}</ref>
* On October 18, 1985, a Jordanian Airlines L-1011 experienced an inflight fire at 24,000 feet while on approach to Singapore. The fire burned through the rear pressure bulkhead, causing [[Engineering:Uncontrolled decompression|explosive depressurization]] of the cabin. The air rushing out of the cabin extinguished the fire, saving the aircraft. All 118 passengers and crew survived. The aircraft was later repaired and placed back into service.<ref>{{ASN accident|id=19851018-0|accessdate=November 18, 2020|title=JY-AGE}}</ref><ref>{{cite book |last= Hill |first= Richard D. |url= http://www.fire.tc.faa.gov/pdf/fsr-0403.pdf |title= Investigations and characteristics of major fire-related accidents in civil air transports over the last ten years |publisher= Federal Aviation Administration Technical Center |access-date= August 25, 2012}}</ref>
* On May 3, 1986, Air Lanka Flight 512 (now SriLankan Airlines), an L-1011, was destroyed on the ground in Colombo, Sri Lanka, after a bomb exploded in the rear cargo hold, severing the tail and killing 21 people.<ref>{{cite news |title=1986: Bomb kills 21 in Sri Lanka |url=http://news.bbc.co.uk/onthisday/hi/dates/stories/may/3/newsid_2481000/2481291.stm |publisher=BBC |date=May 3, 1986}}</ref>
* On June 28, 1991, LTU International L-1011 registration D-AERI, suffered an interior fire during maintenance in a hangar at Düsseldorf Airport. Four engineers escaped injury, but the aircraft was declared a total loss.<ref>{{cite web|title=Accident information : Lockheed L-1011 TriStar LTU International D-AERI|url=https://aviation-safety.net/database/record.php?id=19910628-4|website=Aviation Safety Network|access-date=June 17, 2019}}</ref>
* On July 30, 1992, TWA Flight 843, an L-1011, had its takeoff aborted by the captain after liftoff from JFK, in response to a false stall warning. The aircraft landed too hard, breaking a wing spar and starting a fire. All 292 passengers and crew evacuated safely, with only 10 minor injuries. The airliner was destroyed by fire.<ref>{{cite book |url= http://www.airdisaster.com/reports/ntsb/AAR93-04.pdf |title= Aircraft Accident Report, Trans World Airlines Flight 843 |archive-url=https://web.archive.org/web/20070615113908/http://www.airdisaster.com/reports/ntsb/AAR93-04.pdf |archive-date=June 15, 2007 |publisher= National Transportation Safety Board |url-status= usurped |date= March 31, 1993}}</ref>
* On August 23, 1995, Delta Air Lines Flight 157, an L-1011 Tristar 1, suffered a rapid decompression after the pressure bulkhead failed. The flight crew initiated an emergency descent to 14,000 feet, and the plane landed safely at Los Angeles International Airport with no deaths or injuries to the 226 passengers or 10 crew. However, the aircraft was substantially damaged and later written off.<ref>{{cite web|url= https://aviation-safety.net/database/record.php?id=19950823-0|title= Accident Description|publisher= Aviation Safety Network|date= August 23, 1995|access-date= July 7, 2020}}</ref>

==Aircraft on display==
{{multiple image
 |total_width= 400
 |align= right
 |caption_align= center
 |image1= RSAF Museum Lockheed L-1011 Tristar.jpg
 |caption1= 
 |image2= Lockheed TriStar back.jpg
 |caption2= 
 |footer_background= 
 |footer_align= center
 |footer= Tristar at Royal Saudi Airforce Museum, Riyadh
}}

* N1011{{Snd}} L-1011-1 on display at the Delta Flight Museum in Atlanta, Georgia. This is the forward upper fuselage of the prototype aircraft and is painted in Delta colors.<ref>{{cite web |title=Prototype Lockheed L-1011 |url=http://www.deltamuseum.org/exhibits/exhibits/aircraft/prototype-lockheed-l-1011 |website=Delta Flight Museum |access-date=June 9, 2016}}</ref>
* C-FTNA{{Snd}} L-1011-1 on display at the Lyon–Saint-Exupéry Airport in Lyon, France.  After Air Transat flight TSC906 was damaged in a hailstorm, the plane returned to Lyon and was written off. It is still used today for emergency training.<ref>{{cite web|title=Accident information : Lockheed L-1011 TriStar Air Transat C-FTNA|url=https://aviation-safety.net/database/record.php?id=20010706-1|website=Aviation Safety Network|access-date=June 18, 2018}}</ref><ref>{{google maps|title= 45.7112164°N, 5.0838171°E |url= https://www.google.com/maps/@45.7112164,5.0838171,101m/data=!3m1!1e3 |access-date=June 18, 2018}}</ref>
* N31019{{Snd}} L-1011-50 on display at the National Airline History Museum in Kansas City, Missouri, at the Charles B. Wheeler Downtown Airport.<ref>{{cite web |title=Lockheed L-1011 TriStar |url=http://www.airlinehistory.org/the-aircraft/l-1011 |publisher=Airline History Museum |access-date=September 20, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160815030140/http://www.airlinehistory.org/the-aircraft/l-1011/ |archive-date=August 15, 2016 }}</ref>
* TT-DWE{{Snd}} L-1011-100 on display at the Emirates National Auto Museum in [[Place:Abu Dhabi|Abu Dhabi]], United Arab Emirates. This aircraft was originally delivered to British Airways.<ref>{{cite web|last1=Löffler|first1=Dennis|title=Photo: TT-DWE (CN: 193N-1093) Lockheed L-1011-385 Tristar by Dennis Löffler Photoid:6854229|url=http://www.jetphotos.net/photo/6854229|website=JetPhotos.Net|access-date=September 20, 2016|date=April 6, 2010}}</ref>
* HZ-AHP{{Snd}} L-1011-200 in Saudia livery on display as a gate guardian at the {{wipe|Royal Saudi Air Force Museum}} in [[Place:Riyadh|Riyadh]], Saudi Arabia.<ref>{{cite web|title=Airframe Dossier: Lockheed L-1011-200 TriStar, c/n 1190, c/r HZ-AHP|url=http://aerialvisuals.ca/AirframeDossier.php?Serial=165721|website=Aerial Visuals|access-date=September 20, 2016}}</ref>
* 9Y-TGN{{Snd}} L-1011-500 on display at the Chaguaramas Military History and Aerospace Museum in Chaguaramas, Trinidad. This aircraft was previously operated by BWIA West Indies Airways.<ref>{{cite web |url= http://www.fodors.com/world/caribbean/trinidad-and-tobago/review-175756.html |title= Chaguaramas Military History & Aerospace Museum |work= Trinidad and Tobago Sights |publisher= Fodor's |access-date= July 16, 2011}}</ref><ref>{{cite web|title=Lockheed L-1011-500 Tristar Original model: L1011-500 9Y-TGN|url=http://www.jetphotos.net/census/aircraft2.php?msnid=L1011-193G-1191|website=JetPhotos.Net|access-date=September 20, 2016}}</ref>
* N910TE{{Snd}} L-1011-1 on display with Tristar Experience at Kansas City International Airport. It was previously in storage in Tucson after being retired by the Flying Hospital group as P4-MED in favor of an MD-10. N910TE is the only L-1011-1 with operating RB211-22b engines, and is the only L-1011 other than StarGazer maintained in airworthy condition.<ref>{{Cite news|url=https://fox4kc.com/2017/07/16/jumbo-jet-arrives-at-kci-to-serve-as-stem-classroom-for-students/|title=Jumbo jet arrives at KCI to serve as STEM classroom for students|date=July 16, 2017}}</ref><ref name="tristarhistory">{{cite web |url= http://tristarhistory.org/l1011-n91011/ |title= TriStar L1011 / N91011 |work= TriStar History |access-date= March 28, 2015 |archive-date= March 27, 2015 |archive-url= https://web.archive.org/web/20150327094657/http://tristarhistory.org/l1011-n91011/ |url-status= dead }}</ref><ref>{{cite web|title=TriStar History and Preservation, Inc. to preserve a former TAP Air Portugal Lockheed L-1011 TriStar in TWA colors at Kansas City|url=https://worldairlinenews.com/2015/01/10/tristar-history-and-preservation-inc-to-preserve-a-former-tap-air-portugal-lockheed-l-1011-tristar-in-twa-colors-at-kansas-city|website=World Airline News|access-date=June 9, 2016|date=January 10, 2015}}</ref>
* HS-AXE (Thai Sky Airlines), formerly N718DA (Delta) L-1011-1 was converted to a bar/restaurant located in Bangkok, Thailand.<ref>{{Cite web|url=https://www.changchuibangkok.com/|title=Changchui &#124; Thailand &#124; ช่างชุ่ย ChangChui|website=ChangChui}}</ref>
* 9Q-CHC (Hewa Bora Airways), MSN 1209 formerly C-GAGI (Air Canada) and N767DA (Delta) L-1011-385-3 Tristar 500 moved to Parc de la Vallée de la Nsele near [[Place:Kinshasa|Kinshasa]], Democratic Republic of the Congo where it will be converted to a bar/restaurant.<ref>{{Cite web |url=https://www.aviation24.be/defunct-airlines/hewa-bora/hidden-gem-lockheed-l-1011-tristar-parc-de-la-vallee-de-la-nsele-congo-kinshasa|title=&#91;Hidden Gem&#93; Hewa Bora Airways' Lockheed L-1011 TriStar - Parc de la Vallée de la Nsele, Congo-Kinshasa|date=September 14, 2019}}</ref>
* CS-TMP (Luzair) MSN 1248 formerly JY-AGJ (Royal Jordanian) L-1011-385-3 Tristar 500 moved to Underwater Military Museum Dive Site, Aqaba, Jordan on 26 August 2019 for use as a tourist dive site.<ref>{{Cite web |url=https://www.jetphotos.com/photo/9446772 |title= A Lockheed L-1011 Tristar plane is submerged in the Red Sea in Aqaba|author= Wojtek Kmiecik |date= 28 June 2019 |work= JetPhotos.com |accessdate= 2 March 2021}}</ref><ref>{{cite web |url= https://www.scubadivermag.com/lockheed-tristar-joins-aqaba-military-museum/ |title= Lockheed TriStar joins Aqabas Underwater Military Museum |author= Mark Evans |date= 14 May 2020 |work= Scuba Diver Magazine |accessdate= 2 March 2021}}</ref>
* N102CK (Gee Bee Airways), MSN 1198, in Kitty Hawk basic colours, formerly G-BHBM (British Airways) L-1011 Tristar 200F, stored at the apron of Kavala Airport LGKV/KVA - Greece, since November 2004. 
*N388LS, the former [[Company:Las Vegas Sands|Las Vegas Sands]] L-1011-500, was damaged beyond repair in 2013 by floods while it was parked at Bangkok Airport. In 2018, the aircraft's body was disassembled and reassembled for display at Chic Chic Market, Nong Khai.<ref>{{Cite web|title=N388LS Las Vegas Sands Corporation Lockheed L-1011 Tristar|url=https://www.planespotters.net/airframe/lockheed-l-1011-tristar-n388ls-las-vegas-sands-corporation/ekdovl|access-date=2021-04-15|website=www.planespotters.net|language=en}}</ref>

==Specifications==
[[File:Lockheed L-1011 TriStar v1.0.png|thumb|upright=1.4|Lockheed L-1011-500 TriStar blueprint drawing]]

{| class=wikitable style="text-align: center;"
!Variant
!L-1011-1
!L-1011-200
!L-1011-500
|-
!Cockpit crew
| colspan=3 |Three
|-
!Seating
| colspan=2|256 (mixed-class) || 246 (mixed-class)
|-
!Exit limit
| colspan="2" | 400 || 330
|-
!Interior width
| colspan=3 | {{convert|18|ft|11|in|m}}
|-
!Length
| colspan=2 | {{convert|177|ft|8+1/2|in|m|2|abbr=on}} || {{convert|164|ft|2+1/2|in|m|2|abbr=on}}
|-
!Wingspan
| colspan=2 | {{convert|155|ft|4|in|m|abbr=on}} || {{convert|164|ft|4|in|m|abbr=on}}
|-
!Height
| colspan=3 | {{convert|55|ft|4|in|m|abbr=on}}
|-
!Wing area
| colspan=2 | {{convert|3456|ft2|m2|abbr=on}}|| {{convert|3541|ft2|m2|abbr=on}}
|-
!MTOW
| {{convert|430000|lb|kg|abbr=on|lk=on}} || {{convert|466000|lb|kg|0|abbr=on}} || {{convert|510000|lb|kg|0|abbr=on}}
|-
![[Engineering:Operating empty weight|OEW]]
| {{convert|241700|lb|kg|sigfig=3|abbr=on}} || {{convert|248400|lb|kg|sigfig=3|abbr=on}} || {{convert|245400|lb|kg|sigfig=3|abbr=on}}
|-
! Fuel capacity
| {{convert|23814|gal|L|abbr=on}} || {{convert|26502|gal|L|abbr=on}} || {{convert|31642|gal|L|abbr=on}}
|-
!Engines (×3)
| [[Engineering:Rolls-Royce RB211|Rolls-Royce RB211]]-22 || colspan=2 |RB.211-524B
|-
! Thrust (×3)
| {{convert|42000|lbf|kN|sigfig=3|abbr=on}} || colspan=2 | {{convert|50000|lbf|kN|sigfig=3|abbr=on}}
|-
!Mmo<ref name=TCDS/>
| colspan=3 | {{cvt|0.90|Mach|altitude_ft=42000|kn km/h|0}}
|-
!Cruise{{efn|{{convert|30000|ft|m|abbr=on}}}}
| {{convert|520|kn|km/h|0|lk=in|abbr=on}}|| {{convert|515|kn|km/h|abbr=on}} || {{convert|525|kn|km/h|abbr=on}}
|-
!Stall{{efn|max. landing weight, flaps and gear down}}
|{{convert|108|kn|km/h|0|abbr=on}} || {{convert|110|kn|km/h|0|abbr=on}} || {{convert|114|kn|km/h|0|abbr=on}}
|-
!Range{{efn|max. passengers + baggage}}
| {{convert|2680|nmi|km|0|lk=in|abbr=on}} || {{convert|3600|nmi|km|0|abbr=on}} || {{convert|5345|nmi|km|0|abbr=on}}
|-
!Ferry range{{efn|max. fuel}}
| {{convert|4250|nmi|km|0|abbr=on}} || {{convert|4935|nmi|km|0|abbr=on}} || {{convert|6090|nmi|km|0|abbr=on}}
|-
!Ceiling<ref name=TCDS>{{cite web |url= https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/5342e492984e8616862576ac0055feb3/$FILE/a23we.pdf |title= Type Certificate No. A23WE |publisher= Federal Aviation Administration |date= January 11, 2010}}</ref>
| colspan=2 |{{convert|42000|ft|m|sigfig=3|abbr=on}}|| {{convert|43000|ft|m|sigfig=3|abbr=on}}
|}
{{Notelist}}

===Deliveries===
{| class="wikitable"
|-
! 1972 !! 1973 !! 1974 !! 1975 !! 1976 !! 1977 !! 1978 !! 1979 !! 1980 !! 1981 !! 1982 !! 1983 !! 1984 !! 1985 !! Total
|-
|   17 ||   39 ||   41 ||   24 ||   16 ||   12 ||    8 ||   14 ||   24 ||   28 ||   13 ||    5 ||    5 ||    3 ||   249
|}

==Popular culture==
<!-- ===============({{NoMoreCruft}})===============-->
<!-- Please READ Wikipedia:WikiProject Aircraft/page content#Popular culture before adding any "Popular culture" items.

Please do not add the many minor appearances of the aircraft. This section is only for major cultural appearances where the aircraft plays a MAJOR part in the story line or has an "especially notable" role in what is listed. A verifiable source proving the appearance's notability may be required. Random cruft, including ALL Ace Combat, Battlefield, and Metal Gear Solid appearances, and ALL anime/fiction lookalike speculation, WILL BE removed.

If your item has been removed, please discuss it on the talk page FIRST. A verifiable source proving the appearance's notability may be required. If a consensus is reached to include your item, a regular editor of this page will add it back. Thank you for your cooperation.-->
<!-- ===============({{NoMoreCruft}})=============== -->
* The band El Ten Eleven, a Los Angeles post-rock duo, derives its name from the L-1011.<ref>{{cite web |last= Levine |first= Matthew |url= http://www.cmj.com/reviews/el-ten-eleven-transitions/ |title= El Ten Eleven Transitions (Fake, 2012) |archive-url=https://web.archive.org/web/20130523082726/http://www.cmj.com/reviews/el-ten-eleven-transitions/ |archive-date=May 23, 2013 |work= Bar None Records |date= November 6, 2012 |access-date= November 13, 2012}}</ref>
<!--
  Read the note at top about notability; take any potentially contentious submissions to the article's talk page first.
-->

==See also==
{{aircontent
|see also=
|related=
* [[Engineering:Lockheed TriStar (RAF)|Lockheed TriStar (RAF)]]
* [[Engineering:Stargazer (aircraft)|Stargazer (aircraft)]]
|similar aircraft=
* [[Engineering:Airbus A300|Airbus A300]]
* [[Engineering:Boeing 747SP|Boeing 747SP]]
* [[Engineering:Boeing 767|Boeing 767]]
* [[Engineering:Ilyushin Il-86|Ilyushin Il-86]]
* [[Engineering:McDonnell Douglas DC-10|McDonnell Douglas DC-10]]
|lists=
* List of Lockheed aircraft
* [[Engineering:List of jet airliners|List of jet airliners]]
}}

==References==
'''Notes'''
{{Reflist|group=Note}}

'''Citations'''
{{Reflist}}

==Further reading==
{{Refbegin}}
* {{cite book |last= Bright |first= C. D. |title= The Jet Makers: The Aerospace Industry from 1945 to 1972 |location= Lawrence |publisher= University Press of Kansas |year= 1978 |isbn= 0-7006-0172-4}}
* {{cite book |last= Ingells |first= D. J. |title= L-1011 TriStar and the Lockheed Story |location= Blue Ridge Summit, Pennsylvania |publisher= TAB-Aero |year= 1973 |isbn= 978-0-8168-6650-2}}
* {{cite book |last= Newhouse |first= John |title= The Sporty Game: The High-Risk Competitive Business of Making and Selling Commercial Airliners |location= New York |publisher= Alfred A. Knopf |year= 1982 |isbn= 978-0-394-51447-5}}
* {{cite book |last= Yenne |first= Bill |title= Lockheed |location= New York |publisher= Crescent Books |year= 1987 |isbn= 0-517-60471-X}}
{{Refend}}

==External links==
{{Commons|Lockheed TriStar}}
* {{citation |url= http://www.flightglobal.com/pdfarchive/view/1967/1967%20-%202114.html |archive-url= https://web.archive.org/web/20150105204917/http://www.flightglobal.com/pdfarchive/view/1967/1967%20-%202114.html |url-status= dead |archive-date= 5 January 2015 |title= Presenting the Lockheed L-1011 |magazine= Flight |date= 2 November 1967}}
* {{cite web |url= https://www.tristar500.net/library/technicalprofile.pdf |title= L-1011-500 TriStar technical profile |publisher= Lockheed |date= 1980}}
* {{cite web |url= https://www.forecastinternational.com/archive/disp_old_pdf.cfm?ARC_ID=346 |archive-url= https://web.archive.org/web/20180724183725/https://www.forecastinternational.com/archive/disp_old_pdf.cfm?ARC_ID=346 |url-status= dead |archive-date= 2018-07-24 |title= Lockheed L-1011 TriStar |date= Aug 2001 |publisher= Forecast International}}
* {{citation |url= http://www.airliners.net/aircraft-data/lockheed-l-1011-tristar-150100150200250/271 |title= Aircraft Technical Data & Specifications - Lockheed L-1011 |work= The International Directory of Civil Aircraft |author= Gerard Frawley |via= Airliners.net |date= 2003}}
* {{cite news |url= https://www.flightglobal.com/in-focus-the-tristar-heritage-40-years-on/104584.article |title= The TriStar heritage 40 years on |author= David Learmount |date= 20 April 2012 |work= Flightglobal}}
* {{citation |url= http://www.tristar500.net |title= TriStar500 |author= Andre Malhao |quote= non-commercial and unofficial website |date= 1999–2020}}
* {{citation |url= http://www.airfleets.net/listing/l10-1.htm |title= Production list |work= airfleets.net |date= 2002–2020}}

{{Lockheed Martin aircraft}}

[[Category:Trijets]]
[[Category:Low-wing aircraft]]
[[Category:Wide-body aircraft]]

{{Sourceattribution|Lockheed L-1011 TriStar}}