<!-- This article is a part of Wikipedia:WikiProject Aircraft. Please see Wikipedia:WikiProject Aircraft/page content for recommended layout, and guidelines. -->

The Lockheed L-1011 TriStar (pronounced "El-ten-eleven") is an American medium-to-long-range, wide-body trijet airliner built by the Lockheed Corporation. It was the third wide-body airliner to enter commercial operations, after the Boeing 747 and the McDonnell Douglas DC-10. The airliner has a seating capacity of up to 400 passengers and a range of over . Its trijet configuration has three Rolls-Royce RB.211 engines with one engine under each wing, and a third engine center-mounted in the rear fuselage with an S-duct air inlet on the top of the fuselage. The aircraft has an autoland capability, an automated descent control system, and available lower deck 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 California north of Los Angeles. After L-1011 production ended, Lockheed withdrew from the commercial aircraft business due to its below-target sales. As of 2026, only one L-1011 is in service, as Stargazer.

Development

thumb|Prototype L-1011 TriStar being prepared for its first flight test in 1970

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. Lockheed had not produced civilian airliners since 1961 with the L-188 Electra. In the 1950s the Electra was designed for turboprop propulsion, which Lockheed successfully used on the 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 Boeing 707 and Douglas DC-8. 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 would later capture a much larger civilian airliner market for 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 DC-10, which had a similar three-engine configuration and dimensions. 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 even at the expense of safety", and the conservative approach meant reusing 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 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. The advanced technology that went into the TriStar resulted in a high purchase price.

thumb|[[TWA Lockheed L-1011-1 Tristar twin-aisle cabin in 1972]]

thumb|Lockheed L-1011 TriStar front view showing 3-engine layout

thumb|The S-duct configuration with the air intake offset above the rear engine

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. Lockheed was able to keep the pressure loss in the S-duct similar to that in a straight duct by limiting the duct curvature. Incorporating the S-duct made the airframe lighter than with a straight duct installation. 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. A further major difference between the L-1011 and the DC-10 was Lockheed's selection of the Rolls-Royce RB.211 as the only engine option for the L-1011. As originally designed, the RB.211 turbofan was an advanced three-spool design with a carbon fiber fan, which would have better efficiency and power-to-weight ratio than any competing engine like the 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. Without the support of American, the TriStar was launched on orders from Trans World Airlines (TWA) and Eastern Air Lines.

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 RB.211, Rolls-Royce went into receivership. This halted L-1011 final assembly and Lockheed investigated the possibility of a US engine supplier. 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.

The British government agreed to approve a large state subsidy to restart Rolls-Royce operations on condition that the U.S. government guarantee the bank loans Lockheed needed to complete the L-1011 project. Despite some opposition, not least from the then governor of California, Ronald Reagan, the U.S. government provided these guarantees. For the rest of the RB.211 project, Rolls-Royce remained a government-owned company.

Production

thumb|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 L-1011 first flew on November 16, 1970. The L-1011 was certified on April 14, 1972, with the first airliner delivered to Eastern Air Lines on April 26, 1972. 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".

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.

The TriStar's failure to achieve profitability caused Lockheed to withdraw from the civilian aircraft business.

Reversers and nozzle

thumb|The two parts of the bypass thrust reverser are shown in their operating positions. The black grid of turning vanes allows the air to escape in a forward direction and the usual rearward flow of air for forward thrust is stopped by the blocker doors visible inside the duct.

The RB.211 has thrust reverse using the bypass air from the fan. Reverse is selected when the engine is at idle. An escape path for the air is opened up around the nacelle and blocker doors close off the duct just behind. The air passes through a grid of turning vanes which send the air in a forward direction for reverse thrust.

Initially the RB.211 design also had thrust reversal for the core exhaust. Aerodynamic interference with the flaps diminished the braking effect from the flaps, so the core flow reverser was deleted; in its place an 11-degree afterbody was incorporated, 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." 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.

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.

thumb|Coach cabin of a TWA L-1011 TriStar in 2–5–2 layout

Landing gear

The nose landing gear had two attachment points forward and aft, allowing a short-enough 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. The L-1011 used an inertial navigation system to navigate; this included aligning the navigation system by entering current coordinates of longitude and latitude. 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.

Other components and systems

The APU, which was the Pratt and Whitney ST6L, 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.

Delta Air Lines was the type's largest customer. 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 Airbus A330-300. TWA retired its remaining L-1011s in September 1997.

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. 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. Within Lockheed, board chairman Daniel Haughton and vice chairman and president Carl Kotchian resigned their posts on February 13, 1976. Tanaka was eventually tried and found guilty of violating foreign exchange control laws but was not charged with bribery, a more serious criminal offense. Crucially for Lockheed, the fallout from the scandal included the loss of a contract worth over $1 billion.

The Soviet Union at that time lacked a widebody airliner. Development of its own Ilyushin Il-86 was delayed; consequently, in the mid-1970s, the Soviets started negotiations to buy 30 TriStars and license-produce up to 100 a year. The talks collapsed as US President Jimmy Carter made human rights an important consideration in US foreign policy. 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. 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 charter and wet leasing businesses. 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

The TriStar has also been used as a military tanker and passenger/cargo aircraft. The British Royal Air Force had nine aircraft of four variants. The aircraft were six ex-British Airways and three Pan Am L-1011-500s. 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 Airbus A330 MRTT under the Future Strategic Tanker Aircraft <!-- (FSTA) --> program. 216 Squadron was officially disbanded on March 20, 2014, and flew its last sorties with the TriStar on March 24, 2014.

Other

thumb|[[Northrop Grumman|Northrop Grumman's L-1011-100 "Stargazer" preparing for a flight, with the fuselage lifted to make the room for mounting Pegasus XL rocket]]

In the early 1990s, Orbital Sciences began to use a converted L-1011-100 named Stargazer to launch Pegasus rockets into orbit around Earth. This venture effectively rendered the small Scout rocket obsolete. This aircraft was also used in support of the X-34 and X-43 programs. NASA performed aerodynamic research on Orbital Sciences' L-1011 in 1995. In 2014, three L-1011s in the world were airworthy. As of 2019, Stargazer is the only active L-1011.

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 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

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. This variant was also one of the few widebodies to have the option for a full-height built-in airstair.

Accidents and incidents

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 aviation occurrences, including 10 hull-losses, with 540 fatalities. Of the four pioneering widebody aircraft (Boeing 747, McDonnell Douglas DC-10, L-1011, and Airbus A300/A310 family), the Lockheed L-1011 had comparatively few accidents and a better safety record than its competitors.

  • 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.
  • On April 19, 1974, an L-1011 owned by TWA with the fleet number of 11007 caught fire at Logan Airport in Boston. It had landed four hours previously and there was no one on board. It was subsequently written off.
  • 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. This failure resulted in a large noseup and rolling moment that almost exceeded the capability of the flight controls. The airplane was just about to stall in the clouds when Captain Jack McMahan, 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. 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." According to an incident analysis by Warren VanderBurgh, comprehensive crew training played a critical role in control recovery.
  • 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 Riyadh's former 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 301 occupants.
  • 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.
  • 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 , while en route to San Juan, Puerto Rico. 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.
  • On May 5, 1983, Eastern Air Lines Flight 855, an L-1011 with 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 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.
  • On April 5, 1984, a Saudia Lockheed L-1011 TriStar on final approach to Damascus from Jeddah was hijacked by a Syrian national. The hijacker demanded to be taken to Istanbul, Turkey, but changed his mind and requested to go to Stockholm. After landing in Istanbul to refuel, the pilot pushed the hijacker out the emergency exit whereupon he was arrested.

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, but was eventually repaired and returned to service.
  • On August 2, 1985, Delta Air Lines Flight 191, an L-1011, crashed while approaching Dallas/Fort Worth International Airport in microburst conditions. Eight of 11 crew members and 128 of the 152 passengers on board died, as well as one person on the ground after his vehicle was struck by the L-1011.
  • On October 18, 1985, a Jordanian Airlines L-1011 experienced an inflight fire at while on approach to Singapore. The fire burned through the rear pressure bulkhead, causing 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.
  • 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 resulting in 21 deaths.
  • 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, and the aircraft was declared a total loss.
  • On July 30, 1992, TWA Flight 843, an L-1011, had its takeoff aborted by the captain after liftoff from John F. Kennedy International Airport, 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.
  • 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 , and the plane landed safely at Los Angeles International Airport with no deaths or injuries to the 226 passengers or 10 crew. The aircraft was substantially damaged and later written off.

Aircraft on display

  • N1011 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.
  • C-FTNA 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.
  • N31019 L-1011-50 on display at the National Airline History Museum in Kansas City, Missouri, at the Charles B. Wheeler Downtown Airport. Its original operator was Trans World Airlines.
  • TT-DWE L-1011-100 on display at the Emirates National Auto Museum in Abu Dhabi, United Arab Emirates. This aircraft was originally delivered to British Airways.
  • HZ-AHP L-1011-200 on display originally in the former Saudia paint job as a gate guardian at the Royal Saudi Air Force Museum in Riyadh, Saudi Arabia. In 2018, the plane was repainted to celebrate the 88th Saudi National Day. Since 2019, the paint job now promotes Saudi Vision 2030.
  • 9Y-TGN 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.
  • N910TE 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 working RB.211-22B engines.
  • HS-AXE (Thai Sky Airlines), formerly N718DA (Delta) L-1011-1 was converted to a bar/restaurant located in Bangkok, Thailand.
  • XU-700 (Angel Air), formerly N327EA (Eastern Air Lines) L-1011-1 was converted to a coffee shop located near Pattaya, Thailand.
  • 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 Kinshasa, Democratic Republic of the Congo where it will be converted to a bar/restaurant.
  • 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.
  • 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 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.
  • 9L-LFB, the former All Nippon Airways JA8522, was last operated by Air Rum until 2010. It was stored on a local beach in Cotonou, in the country of Benin, since 2014, and features a preserved interior. Guests can tour the aircraft's interior by paying an entry fee. [https://www.airlinereporter.com/2021/05/exploring-an-abandoned-l1011-tristar-on-a-beach-in-west-africa]

Specifications

thumb|Lockheed L-1011-500 TriStar blueprint drawing

{| class=wikitable style="text-align: center;"

|+ L-1011 Specifications

! 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 |

|-

! Length

| colspan=2 | ||

|-

! Wingspan

| colspan=2 | ||

|-

! Height

| colspan=3 |

|-

! Wing area

| colspan=2 | ||

|-

! MTOW

| || ||

|-

! OEW

| || ||

|-

! Fuel capacity

| || ||

|-

! Engines (×3)

| Rolls-Royce RB.211-22 || colspan="2" |Rolls-Royce RB.211-524

|-

! Thrust (×3)

| || colspan=2 |

|-

! Mmo

| colspan=2 | ||

|}

Notable appearances in media

<!-- ===============()===============-->

<!-- 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.-->

<!-- ===============()=============== -->

  • The band El Ten Eleven, a Los Angeles post-rock duo, derives its name from the L-1011.
  • The parody artist Bob Rivers, wrote a song called "Beat Up Old Jetliner" that mentions the L-1011.

<!-- Read the note at top about notability; take any potentially contentious submissions to the article's talk page first.

-->

See also

References

;Notes

;Citations

Further reading