Boeing 777

The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. The 777 is the world's largest twinjet and the most-built wide-body airliner. The jetliner was designed to bridge the gap between Boeing's other wide body airplanes, the twin-engined 767 and quad-engined 747, and to replace aging DC-10 and L-1011 trijets. Developed in consultation with eight major airlines, the 777 program was launched in October 1990, with an order from United Airlines. The prototype was rolled out in April 1994, and first flew in June. The 777 entered service with the launch operator United Airlines in June 1995. Longer-range variants were launched in 2000, and first delivered in 2004.
The 777 can accommodate a ten–abreast seating layout and has a typical 3-class capacity of 301 to 368 passengers, with a range of 5,240 to 8,555 nautical miles [nmi] (9,700 to 15,840 km; 6,030 to 9,840 mi). The jetliner is recognizable for its large-diameter turbofan engines, six wheels on each main landing gear, fully circular fuselage cross-section, and a blade-shaped tail cone. The 777 became the first Boeing airliner to use fly-by-wire controls and to apply a carbon composite structure in the tailplanes.
The original 777 with a maximum takeoff weight (MTOW) of 545,000–660,000 lb (247–299 t) was produced in two fuselage lengths: the initial 777-200 was followed by the extended-range -200ER in 1997; and the 33.25 ft (10.13 m) longer 777-300 in 1998. These 777 Classics were powered by 77,200–98,000 lbf (343–436 kN) General Electric GE90, Pratt & Whitney PW4000, or Rolls-Royce Trent 800 engines. The extended-range 777-300ER, with a MTOW of 700,000–775,000 lb (318–352 t), entered service in 2004, the longer-range 777-200LR in 2006, and the 777F freighter in 2009. These longer-haul variants use 110,000–115,300 lbf (489–513 kN) GE90 engines and have extended raked wingtips. In November 2013, Boeing announced the 777X development with the -8 and -9 variants, both featuring composite wings with folding wingtips and General Electric GE9X engines.
As of 2018, Emirates was the largest operator with a fleet of 163 aircraft. As of May 2024, more than 60 customers have placed orders for 2,268 Triple Sevens across all variants, of which 1,729 have been delivered. This makes the 777 the best-selling wide-body airliner, while its best-selling variant is the 777-300ER with 837 aircraft ordered and 832 delivered. The airliner initially competed with the Airbus A340 and McDonnell Douglas MD-11; since 2015 it has mainly competed with the Airbus A350 and later also with the A330-900. As of May 2024, the 777 has been involved in 31 aviation accidents and incidents, including five hull loss accidents out of eight total hull losses with 542 fatalities including one ground casualty.
== Development ==
=== Background ===
In the early 1970s, the Boeing 747, McDonnell Douglas DC-10, and the Lockheed L-1011 TriStar became the first generation of wide-body passenger airliners to enter service. In 1978, Boeing unveiled three new models: the twin-engine or twinjet Boeing 757 to replace its 727, the twinjet 767 to challenge the Airbus A300, and a trijet 777 concept to compete with the DC-10 and L-1011. The mid-size 757 and 767 launched to market success, due in part to 1980s' extended-range twin-engine operational performance standards (ETOPS) regulations governing transoceanic twinjet operations. These regulations allowed twin-engine airliners to make ocean crossings at up to three hours' distance from emergency diversionary airports. Under ETOPS rules, airlines began operating the 767 on long-distance overseas routes that did not require the capacity of larger airliners. The trijet 777 was later dropped, following marketing studies that favored the 757 and 767 variants. Boeing was left with a size and range gap in its product line between the 767-300ER and the 747-400.
By the late 1980s, DC-10 and L-1011 models were approaching retirement age, prompting manufacturers to develop replacement designs. McDonnell Douglas was working on the MD-11, a stretched successor of the DC-10, while Airbus was developing its A330 and A340 series. In 1986, Boeing unveiled proposals for an enlarged 767, tentatively named 767-X, to target the replacement market for first-generation wide-bodies such as the DC-10, and to complement existing 767 and 747 models in the company lineup. The initial proposal featured a longer fuselage and larger wings than the existing 767, along with winglets. Later plans expanded the fuselage cross-section but retained the existing 767 flight deck, nose, and other elements. However, airline customers were uninterested in the 767-X proposals, and instead wanted an even wider fuselage cross-section, fully flexible interior configurations, short- to intercontinental-range capability, and an operating cost lower than that of any 767 stretch.
Airline planners' requirements for larger aircraft had become increasingly specific, adding to the heightened competition among aircraft manufacturers. By 1988, Boeing realized that the only answer was a clean-sheet design, which became the twinjet 777. The company opted for the twin-engine configuration given past design successes, projected engine developments, and reduced-cost benefits. On December 8, 1989, Boeing began issuing offers to airlines for the 777.
=== Design effort ===
Alan Mulally served as the Boeing 777 program's director of engineering, and then was promoted in September 1992 to lead it as vice-president and general manager. The design phase of the all-new twinjet was different from Boeing's previous jetliners, in which eight major airlines (All Nippon Airways, American Airlines, British Airways, Cathay Pacific, Delta Air Lines, Japan Airlines, Qantas, and United Airlines) played a role in the development. This was a departure from industry practice, where manufacturers typically designed aircraft with minimal customer input. The eight airlines that contributed to the design process became known within Boeing as the "Working Together" group. At the group's first meeting in January 1990, a 23-page questionnaire was distributed to the airlines, asking what each wanted in the design. By March 1990, the group had decided upon a baseline configuration: a cabin cross-section close to the 747's, capacity up to 325 passengers, flexible interiors, a glass cockpit, fly-by-wire controls, and 10 percent better seat-mile costs than the A330 and MD-11.
The development phase of the 777 coincided with United Airlines's replacement program for its aging DC-10s. On October 14, 1990, United became the launch customer with an order for 34 Pratt & Whitney-powered 777s valued at US$11 billion (~$22.7 billion in 2023) and options for 34 more. The airline required that the new aircraft be capable of flying three different routes: Chicago to Hawaii, Chicago to Europe, and non-stop from Denver, a hot and high airport, to Hawaii. ETOPS certification was also a priority for United, given the overwater portion of United's Hawaii routes. In late 1991, Boeing selected its Everett factory in Washington, home of 747 production, as the 777's final assembly line (FAL). In January 1993, a team of United developers joined other airline teams and Boeing designers at the Everett factory. The 240 design teams, with up to 40 members each, addressed almost 1,500 design issues with individual aircraft components. The fuselage diameter was increased to suit Cathay Pacific, the baseline model grew longer for All Nippon Airways, and British Airways' input led to added built-in testing and interior flexibility, along with higher operating weight options.
The 777 was the first commercial aircraft to be developed using an entirely computer-aided design (CAD) process. Each design drawing was created on a three-dimensional CAD software system known as CATIA, sourced from Dassault Systemes and IBM. This allowed engineers to virtually assemble the 777 aircraft on a computer system to check for interference and verify that the thousands of parts fit properly before the actual assembly process—thus reducing costly rework. Boeing developed its high-performance visualization system, FlyThru, later called IVT (Integrated Visualization Tool) to support large-scale collaborative engineering design reviews, production illustrations, and other uses of the CAD data outside of engineering. Boeing was initially not convinced of CATIA's abilities and built a physical mock-up of the nose section to verify its results. The test was so successful that additional mock-ups were canceled. The 777 was completed with such precision that it was the first Boeing jetliner that didn't require the details to be worked out on an expensive physical aircraft mock-up, helping the program cost just US$5 billion.
=== Testing and certification ===
Major assembly of the first aircraft began on January 4, 1993. On April 9, 1994, the first 777, number WA001, was rolled out in a series of 15 ceremonies held during the day to accommodate the 100,000 invited guests. The first flight took place on June 12, 1994, under the command of chief test pilot John E. Cashman. This marked the start of an 11-month flight test program that was more extensive than testing for any previous Boeing model. Nine aircraft fitted with General Electric, Pratt & Whitney, and Rolls-Royce engines were flight tested at locations ranging from the desert airfield at Edwards Air Force Base in California to frigid conditions in Alaska, mainly Fairbanks International Airport. To satisfy ETOPS requirements, eight 180-minute single-engine test flights were performed. The first aircraft built was used by Boeing's nondestructive testing campaign from 1994 to 1996, and provided data for the -200ER and -300 programs.
At the successful conclusion of flight testing, the 777 was awarded simultaneous airworthiness certification by the US Federal Aviation Administration (FAA) and European Joint Aviation Authorities (JAA) on April 19, 1995.
=== Entry into service ===
Boeing delivered the first Triple Seven to United Airlines on May 15, 1995. The FAA awarded 180-minute ETOPS clearance ("ETOPS-180") for the Pratt & Whitney PW4084-engined aircraft on May 30, 1995, making it the first airliner to carry an ETOPS-180 rating at its entry into service. The first commercial flight took place on June 7, 1995, from London Heathrow Airport to Dulles International Airport near Washington, D.C. Longer ETOPS clearance of 207 minutes was approved in October 1996.
On November 12, 1995, Boeing delivered the first model with General Electric GE90-77B engines to British Airways, which entered service five days later. Initial service was affected by gearbox bearing wear issues, which caused British Airways to temporarily withdraw its 777 fleet from transatlantic service in 1997, returning to full service later that year. General Electric subsequently announced engine upgrades.
The first Rolls-Royce Trent 877-powered aircraft was delivered to Thai Airways International on March 31, 1996, completing the introduction of the three powerplants initially developed for the airliner. Each engine-aircraft combination had secured ETOPS-180 certification from the point of entry into service. By June 1997, orders for the 777 numbered 323 from 25 airlines, including satisfied launch customers that had ordered additional aircraft. Operations performance data established the consistent capabilities of the twinjet over long-haul transoceanic routes, leading to additional sales. By 1998, the 777 fleet had approached 900,000 flight hours. Boeing states that the 777 fleet has a dispatch reliability (rate of departure from the gate with no more than 15 minutes delay due to technical issues) above 99 percent.
=== Improvement and stretching: -200ER/-300 ===
After the baseline model, the 777-200, Boeing developed an increased gross weight variant with greater range and payload capability. Initially named 777-200IGW, the 777-200ER first flew on October 7, 1996, received FAA and JAA certification on January 17, 1997, and entered service with British Airways on February 9, 1997. Offering greater long-haul performance, the variant became the most widely ordered version of the aircraft through the early 2000s. On April 2, 1997, a Malaysia Airlines -200ER named "Super Ranger" broke the great circle "distance without landing" record for an airliner by flying eastward from Boeing Field, Seattle to Kuala Lumpur, a distance of 10,823 nautical miles (20,044 km; 12,455 mi), in 21 hours and 23 minutes.
Following the introduction of the -200ER, Boeing turned its attention to a stretched version of the baseline model. On October 16, 1997, the 777-300 made its first flight. At 242.4 ft (73.9 m) in length, the -300 became the longest airliner yet produced (until the A340-600), and had a 20 percent greater overall capacity than the standard length model. The -300 was awarded type certification simultaneously from the FAA and JAA on May 4, 1998, and entered service with launch customer Cathay Pacific on May 27, 1998.
The first generation of Boeing 777 models, the -200, -200ER, and -300 have since been known collectively as Boeing 777 Classics. These three early 777 variants had three engine options ranging from 77,200 to 98,000 lbf (343 to 436 kN): General Electric GE90, Pratt & Whitney PW4000, or Rolls-Royce Trent 800.
=== Production ===
The production process included substantial international content, an unprecedented level of global subcontracting for a Boeing jetliner, later exceeded by the 787. International contributors included Mitsubishi Heavy Industries and Kawasaki Heavy Industries (fuselage panels), Fuji Heavy Industries, Ltd. (center wing section), Hawker de Havilland (elevators), and Aerospace Technologies of Australia (rudder). An agreement between Boeing and the Japan Aircraft Development Corporation, representing Japanese aerospace contractors, made the latter risk-sharing partners for 20 percent of the entire development program.
To accommodate production of its new airliner, Boeing doubled the size of the Everett factory at the cost of nearly US$1.5 billion (~$2.86 billion in 2023) to provide space for two new assembly lines. New production methods were developed, including a turn machine that could rotate fuselage subassemblies 180 degrees, giving workers access to upper body sections. By the start of production 1993, the program had amassed 118 firm orders, with options for 95 more from 10 airlines. Total investment in the program was estimated at over US$4 billion from Boeing, with an additional US$2 billion from suppliers.
Initially second to the 747 as Boeing's most profitable jetliner, the 777 became the company's most lucrative model in the 2000s. An analyst established the 777 program, assuming Boeing has fully recouped the plane's development costs, may account for US$400 million of the company's pretax earnings in 2000, US$50 million more than the 747. By 2004, the airliner accounted for the bulk of wide-body revenues for Boeing Commercial Airplanes. In 2007, orders for second-generation 777 models approached 350 aircraft, and in November of that year, Boeing announced that all production slots were sold out to 2012. The program backlog of 356 orders was valued at US$95 billion at list prices in 2008.
In 2010, Boeing announced plans to increase production from 5 aircraft per month to 7 aircraft per month by mid-2011, and 8.3 per month by early 2013. In November 2011, assembly of the 1,000th 777, a -300ER, began when it took 49 days to fully assemble each of these variants. The aircraft in question was built for Emirates airline, and rolled out of the production facility in March 2012. By the mid-2010s, the 777 had become prevalent on the longest flights internationally and had become the most widely used airliner for transpacific routes, with variants of the type operating over half of all scheduled flights and with the majority of transpacific carriers. By April 2014, with cumulative sales surpassing those of the 747, the 777 became the best-selling wide-body airliner; at existing production rates, the aircraft was on track to become the most-delivered wide-body airliner by mid-2016.
By February 2015, the backlog of undelivered 777s totaled 278 aircraft, equivalent to nearly three years at the then production rate of 8.3 aircraft per month, causing Boeing to ponder the 2018–2020 time frame. In January 2016, Boeing confirmed plans to reduce the production rate of the 777 family from 8.3 per month to 7 per month in 2017 to help close the production gap between the 777 and 777X due to a lack of new orders. In August 2017, Boeing was scheduled to drop 777 production again to five per month. In 2018, assembling test 777-9 aircraft was expected to lower output to an effective rate of 5.5 per month. In March 2018, as previously predicted, the 777 overtook the 747 as the world's most produced wide body aircraft. Due to the impact of the COVID-19 pandemic on aviation, demand for new jets fell in 2020 and Boeing further reduced monthly 777 production from five to two aircraft.
=== Second generation (777-X): -300ER/-200LR/F ===
From the program's start, Boeing had considered building ultra-long-range variants. Early plans centered on a 777-100X proposal, a shortened variant of the -200 with reduced weight and increased range, similar to the 747SP. However, the -100X would have carried fewer passengers than the -200 while having similar operating costs, leading to a higher cost per seat. By the late 1990s, design plans shifted to longer-range versions of existing models.
In March 1997, the Boeing board approved the 777-200X/300X specifications: 298 passengers in three classes over 8,600 nmi (15,900 km; 9,900 mi) for the 200X and 6,600 nmi (12,200 km; 7,600 mi) with 355 passengers in a tri-class layout for the 300X, with design freeze planned in May 1998, 200X certification in August 2000, and introduction in September and in January 2001 for the 300X. The 4.5 ft (1.37 m) wider wing was to be strengthened and the fuel capacity enlarged, and it was to be powered by simple derivatives with similar fans. GE was proposing a 102,000 lbf (454 kN) GE90-102B, while P&W offered its 98,000 lbf (436 kN) PW4098 and R-R was proposing a 98,000 lbf (437 kN) Trent 8100. Rolls-Royce was also studying a Trent 8102 over 100,000 lbf (445 kN). Boeing was studying a semi-levered, articulated main gear to help the take-off rotation of the proposed -300X, with its higher 715,600 lb (324,600 kg) MTOW. By January 1999, its MTOW grew to 750,700 lb (340,500 kg), and thrust requirements increased to 110,000–114,000 lbf (490–510 kN).
A more powerful engine in the thrust class of 100,000 lbf (440 kN) was required, leading to talks between Boeing and engine manufacturers. General Electric offered to develop the GE90-115B engine, while Rolls-Royce proposed developing the Trent 8104 engine. In 1999, Boeing announced an agreement with General Electric, beating out rival proposals. Under the deal with General Electric, Boeing agreed to only offer GE90 engines on new 777 versions.
On February 29, 2000, Boeing launched its next-generation twinjet program, initially called 777-X, and began issuing offers to airlines. Development was slowed by an industry downturn during the early 2000s. The first model to emerge from the program, the 777-300ER, was launched with an order for ten aircraft from Air France, along with additional commitments. On February 24, 2003, the -300ER made its first flight, and the FAA and EASA (European Aviation Safety Agency, successor to the JAA) certified the model on March 16, 2004. The first delivery to Air France took place on April 29, 2004. The -300ER, which combined the -300's added capacity with the -200ER's range, became the top-selling 777 variant in the late 2000s, benefitting as airlines replaced comparable four-engine models with twinjets for their lower operating costs.
The second long-range model, the 777-200LR, rolled out on February 15, 2005, and completed its first flight on March 8, 2005. The -200LR was certified by both the FAA and EASA on February 2, 2006, and the first delivery to Pakistan International Airlines occurred on February 26, 2006. On November 10, 2005, the first -200LR set a record for the longest non-stop flight of a passenger airliner by flying 11,664 nautical miles (21,602 km; 13,423 mi) eastward from Hong Kong to London. Lasting 22 hours and 42 minutes, the flight surpassed the -200LR's standard design range and was logged in the Guinness World Records.
The production freighter model, the 777F, rolled out on May 23, 2008. The maiden flight of the 777F, which used the structural design and engine specifications of the -200LR along with fuel tanks derived from the -300ER, occurred on July 14, 2008. FAA and EASA type certification for the freighter was received on February 6, 2009, and the first delivery to launch customer Air France took place on February 19, 2009.
By the late 2000s, the 777 was facing increased potential competition from Airbus' planned A350 XWB and internally from proposed 787 series, both airliners that offer fuel efficiency improvements. As a consequence, the 777-300ER received engine and aerodynamics improvement packages for reduced drag and weight. In 2010, the variant further received a 5,000 lb (2,300 kg) maximum zero-fuel weight increase, equivalent to a higher payload of 20–25 passengers; its GE90-115B1 engines received a 1–2.5 percent thrust enhancement for increased takeoff weights at higher-altitude airports. Through these improvements, the 777 remains the largest twin-engine jetliner in the world,
In 2011, the 787 Dreamliner entered service, the completed first stage a.k.a. the Yellowstone-2 (Y2) of a replacement aircraft initiative called the Boeing Yellowstone Project, which would replace large variants of the 767 (300/300ER/400) but also small variants of the 777 (-200/200ER/200LR). While the larger variants of the 777 (-300/300ER) as well as the 747 could eventually be replaced by a new generation aircraft, the Yellowstone-3 (Y3), which would draw upon technologies from the 787 Dreamliner (Y2). More changes were targeted for late 2012, including possible extension of the wingspan, along with other major changes, including a composite wing, a new generation engine, and different fuselage lengths. Emirates was reportedly working closely with Boeing on the project, in conjunction with being a potential launch customer for the new 777 generation. Among customers for the aircraft during this period, China Airlines ordered ten 777-300ER aircraft to replace 747-400s on long-haul transpacific routes (with the first of those aircraft entering service in 2015), noting that the 777-300ER's per seat cost is about 20% lower than the 747's costs (varying due to fuel prices).
=== Improvement packages ===
In tandem with the development of the third generation Boeing 777X, Boeing worked with General Electric to offer a 2% improvement in fuel efficiency to in-production 777-300ER aircraft. General Electric improved the fan module and the high-pressure compressor stage-1 blisk in the GE-90-115 turbofan, as well as reduced clearances between the tips of the turbine blades and the shroud during cruise. These improvements, of which the latter is the most important and was derived from work to develop the 787, were stated by GE to lower fuel burn by 0.5%. Boeing's wing modifications were intended to deliver the remainder. Boeing stated that every 1% improvement in the 777-300ER's fuel burn translates into being able to fly the aircraft another 75 nmi (139 km; 86 mi) on the same load of fuel, or add ten passengers or 2,400 lb (1,100 kg) of cargo to a "load limited" flight.
In March 2015, additional details of the improvement package were unveiled. The 777-300ER was to shed 1,800 lb (820 kg) by replacing the fuselage crown with tie rods and composite integration panels, similar to those used on the 787. The new flight control software was to eliminate the need for the tail skid by keeping the tail off the runway surface regardless of the extent to which pilots command the elevators. Boeing was also redesigning the inboard flap fairings to reduce drag by reducing pressure on the underside of the wing. The outboard raked wingtip was to have a divergent trailing edge, described as a "poor man's airfoil" by Boeing; this was originally developed for the McDonnell Douglas MD-12 project. Another change involved elevator trim bias. These changes were to increase fuel efficiency and allow airlines to add 14 additional seats to the airplane, increasing per seat fuel efficiency by 5%.
Mindful of the long time required to bring the 777X to the market, Boeing continued to develop improvement packages which improve fuel efficiency, as well as lower prices for the existing product. In January 2015, United Airlines ordered ten 777-300ERs, normally costing around US$150 million each but paid around US$130 million, a discount to bridge the production gap to the 777X. In 2019, the -200ER unit cost was US$306.6 million, the -200LR: US$346.9 million, the -300ER: US$375.5 million and the 777F US$352.3 million. The -200ER is the only Classic variant listed.
=== Third generation (777X): -8/-8F/-9 ===
In November 2013, with orders and commitments totaling 259 aircraft from Lufthansa, Emirates, Qatar Airways, and Etihad Airways, Boeing formally launched the 777X program, the third generation of the 777, with two models: the 777-8 and 777-9. The 777-9 is a further stretched variant with a capacity of over 400 passengers and a range of over 8,200 nmi (15,200 km; 9,400 mi), whereas the 777-8 is slated to seat approximately 350 passengers and have a range of over 9,300 nmi (17,200 km; 10,700 mi). Both models are to be equipped with new generation GE9X engines and feature new composite wings with folding wingtips. The first member of the 777X family was projected to enter service in 2020 at the time of the program announcement. The roll-out of the prototype 777X, a 777-9 model, occurred on March 13, 2019. The 777-9 first flew on January 25, 2020, with deliveries initially forecast for 2022 or 2023 and later delayed to 2025.
== Design ==