Boeing 777

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 7N7 (later named Boeing 757) to replace its 727, the twinjet Boeing 7X7 (later named 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. 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 expected to be retired in the next decade, prompting manufacturers to develop replacement designs. McDonnell Douglas was working on the MD-11, a stretched successor of the DC-10, to target the replacement market for first-generation wide-bodies such as the DC-10, The initial proposal featured a longer fuselage and larger wings than the existing 767, Later plans expanded the fuselage cross-section but retained the existing 767 flight deck, nose, and other elements. 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. The design phase of the all-new twinjet was different from Boeing's previous jetliners; 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 777 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. On October 14, 1990, United became the launch customer with an order for 34 Pratt & Whitney-powered 777s valued at US$11 billion (~$ in ) 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. given the overwater portion of United's Hawaii routes. In late 1991, Boeing selected its Everett factory in Washington, home of 747 (and later 787) 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, 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 Systèmes 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 did not require the details to be worked out on an expensive physical aircraft mock-up. This helped the design program to limit costs to a reported $5 billion. Testing and certification on June 12, 1994.|alt=Side view of a twin-engine jet in flight, surrounded by white clouds 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 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. 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, The first Rolls-Royce Trent 877-powered aircraft was delivered to Thai Airways International on March 31, 1996, Each engine-aircraft combination had secured ETOPS-180 certification from its entry into service. By June 1997, orders for the 777 numbered 323 from 25 airlines, including launch customers that had ordered additional aircraft. 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 introduced the stretched -300 variant on May 27, 1998. After the baseline model, the 777-200, Boeing developed an increased gross weight variant with greater range and payload capability. Initially named 777-200IGW, Offering greater long-haul performance, the variant became the most widely ordered version of the aircraft through the early 2000s. At 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 the Boeing 777 Classics. later exceeded by the 787. International contributors included Mitsubishi Heavy Industries and Kawasaki Heavy Industries (fuselage panels), Fuji Heavy Industries, Ltd. (center wing section), 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. Total investment in the program was estimated at over $4 billion from Boeing, with an additional $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 $400 million of the company's pretax earnings in 2000, $50 million more than the 747. In 2007, orders for second-generation 777 models approached 350 aircraft, 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 one of these variants. The aircraft in question was destined for Emirates, 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 engine of later variants has a 128 in (330 cm) fan diameter up from 123 in (310 cm) in earlier variants, and curved blades instead of straight ones.|alt= Aircraft engine, forward-facing view with a Boeing engineer in front to demonstrate the engine's size. The engine's large circular intake contains a central hub with a swirl mark, surrounded by multiple curved fan blades. 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, However, the -100X would have carried fewer passengers than the -200 while having similar operating costs, leading to a higher cost per seat. Rolls-Royce was also studying a Trent 8102 over . Boeing was also studying a semi-levered, articulated main gear to help the take-off rotation of the proposed -300X, with its higher maximum take-off weight (MTOW). By January 1999, its MTOW grew to , and thrust requirements increased to . A more powerful engine in the thrust class of was required, leading to talks between Boeing and engine manufacturers. General Electric offered to develop the GE90-115B engine, In 1999, Boeing announced an agreement with General Electric, beating out rival proposals. initially called 777-X, along with additional commitments. The first delivery to Air France took place on April 29, 2004. The second long-range model, the 777-200LR, rolled out on February 15, 2005, and completed its first flight on March 8, 2005. 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 eastward from Hong Kong to London. 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 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, 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). 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). 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 GE90-115 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 on the same load of fuel, or add ten passengers or of cargo to a "load limited" flight. In March 2015, additional details of the "improvement package" were unveiled. The 777-300ER was to shed by replacing the fuselage crown with tie rods and composite integration panels, similar to those used on the 787. The new flight control software would 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; 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 selling for around $150 million per aircraft, for $130 million each, a discount to bridge the production gap to the 777X. In 2019, the list price for the -200ER was $306.6 million, the -200LR: $346.9 million, the -300ER: $375.5 million and 777F: $352.3 million. The -200ER is the only Classic variant listed. Third generation (777X): -8/-8F/-9 on March 13, 2019, featuring composite wings with folding wingtips and more efficient GE9X engines. 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 first flew on January 25, 2020, with deliveries initially forecast for 2022 or 2023 and later delayed to 2025 and 2026. In October 2025, Boeing pushed back the first delivery of the 777X to 2027, citing a longer-than-expected regulatory approval process. As a result, the company booked a $4.9 billion noncash charge in its third quarter earnings. ==Design==

Boeing introduced a number of advanced technologies with the 777 design, including fully digital fly-by-wire controls, fully software-configurable avionics, Honeywell LCD glass cockpit flight displays, and the first use of a fiber optic avionics network on a commercial airliner. Boeing made use of work done on the cancelled Boeing 7J7 regional jet, which utilized similar versions of the chosen technologies. In 2013, Boeing announced that the upgraded 777X models would incorporate airframe, systems, and interior technologies from the 787. Fly-by-wire In designing the 777 as its first fly-by-wire commercial aircraft, Boeing decided to retain conventional control yokes rather than change to sidestick controllers as used in many fly-by-wire fighter aircraft and in many Airbus airliners. The fly-by-wire system also incorporates flight envelope protection, a system that guides pilot inputs within a computer-calculated framework of operating parameters, acting to prevent stalls, overspeeds, and excessively stressful maneuvers. Airframe and systems wings, and GE90 turbofan engines, the largest and most powerful jet engine in service until surpassed by the General Electric GE9X. in 2007 with Trent 800 engines, extended slats, flaps, and six-wheel landing gear |alt=Aircraft belly section. Close view of engines, extended landing gear and angled control flaps. The airframe incorporates the use of composite materials, accounting for nine percent of the original structural weight, while the third-generation models, the 777-8 and 777-9, feature more composite parts. Composite components include the cabin floor and rudder, with the 777 being the first Boeing airliner to use composite materials for both the horizontal and vertical stabilizers (empennage). The main fuselage cross-section is fully circular, and tapers rearward into a blade-shaped tail cone with a port-facing auxiliary power unit. The wings on the 777 feature a supercritical airfoil design that is swept back at 31.6 degrees and optimized for cruising at Mach 0.83 (revised after flight tests up to Mach 0.84). The wings are designed with increased thickness and a longer span than previous airliners, resulting in greater payload and range, improved takeoff performance, and a higher cruising altitude. In 2013, a new wing made of composite materials was introduced for the upgraded 777X, with a wider span and design features based on the 787's wings. Folding wingtips reemerged as a design feature at the announcement of the upgraded 777X in 2013. Smaller folding wingtips of in length will allow 777X models to use the same airport gates and taxiways as earlier 777s. The six-wheel bogies are designed to spread the load of the aircraft over a wide area without requiring an additional centerline gear. This helps reduce weight and simplifies the aircraft's braking and hydraulic systems. Each tire of a 777-300ER six-wheel main landing gear can carry a load of , which is heavier than other wide-bodies such as the 747-400. The aircraft has triple redundant hydraulic systems with only one system required for landing. A ram air turbine—a small retractable device which can provide emergency power—is also fitted in the wing root fairing. Interior Boeing 777-300ER in a 3–3–3 layout. Etihad later retrofitted their 777s with a denser 3–4–3 layout. to six–abreast in first class up to ten–abreast in economy. The 777's windows were the largest of any current commercial airliner until the 787, and measure for all models outside the 777-8 and -9. The cabin also features "Flexibility Zones", which entails deliberate placement of water, electrical, pneumatic, and other connection points throughout the interior space, allowing airlines to move seats, galleys, and lavatories quickly and more easily when adjusting cabin arrangements. Boeing designed a hydraulically damped toilet seat cover hinge that closes slowly. In February 2003, Boeing introduced overhead crew rests as an option on the 777. Located above the main cabin and connected via staircases, the forward flight crew rest contains two seats and two bunks, while the aft cabin crew rest features multiple bunks. The 747-8 and 767-400ER have also adopted the larger, more rounded windows of the original 777. In July 2011, Flight International reported that Boeing was considering replacing the Signature Interior on the 777 with a new interior similar to that on the 787, as part of a move towards a "common cabin experience" across all Boeing platforms. With the launch of the 777X in 2013, Boeing confirmed that the aircraft would be receiving a new interior featuring 787 cabin elements and larger windows. While many airlines debuted the 777 with 9-abreast economy cabins, airlines have largely shifted towards denser 10-abreast economy cabins in the 2010s to reduce per-seat costs, with numerous airlines retrofitting their 777 economy cabins with a 10-abreast layout. In 2001, only 5% of 777 deliveries were equipped with 10-abreast economy, while this had risen to over 50% of 777 deliveries by 2016. Air France has a 777-300ER sub-fleet with 472 seats each, more than any other international 777, to achieve a cost per available seat kilometer (CASK) around €.05, similar to Level's 314-seat Airbus A330-200, Air France's benchmark for low-cost long-haul. Engines The initial 777 models (consisting of the 777-200, 777-200ER, 777-300) were launched with propulsion options from three manufacturers, GE Aviation, Pratt & Whitney, and Rolls-Royce, giving the airlines their choice of engines from competing firms. Each manufacturer agreed to develop an engine in the of thrust class for the world's largest twinjet, resulting in the General Electric GE90, Pratt & Whitney PW4000, or Rolls-Royce Trent 800 engines. The Trent 800 is the lightest of the three powerplants as it weighs 13,400 lb (6.078 t) dry, while the GE90 is , and the PW4000 is . The higher-thrust variants, GE90-110B1 and -115B, have a different architecture from that of the earlier GE90 versions. GE incorporated an advanced larger diameter fan made from composite materials which enhanced thrust at low flight speeds. However, GE also needed to increase core power to improve net thrust at high flight speeds. Consequently, GE elected to increase core capacity, which they achieved by removing one stage from the rear of the HP compressor and adding an additional stage to the LP compressor, which more than compensated for the reduction in HP compressor pressure ratio, resulting in a net increase in core mass flow. The higher-thrust GE90 variants are the first production engines to feature swept rotor blades. The nacelle has a maximum diameter of . Each of the 22 fan blades on the GE90-115B have a length of and a mass of less than . ==Variants==

Boeing uses two characteristics – fuselage length and range – to define its 777 models. Passengers and cargo capacity varies by fuselage length: the 777-300 has a stretched fuselage compared to the base 777-200. Three range categories were defined: the A-market would cover domestic and regional operations, the B-market would cover routes from Europe to the US West coast and the C-market the longest transpacific routes. The A-market would be covered by a (7,800 km; ) range, MTOW aircraft for 353 to 374 passengers powered by engines, followed by a (12,200 km; ) B-market range for 286 passengers in three-class, with unit thrust and of MTOW, an A340 competitor, basis of an A-market 409 to 434 passengers stretch, and eventually a (14,000 km; ) C-market with engines. When referring to different variants, the International Air Transport Association (IATA) code collapses the 777 model designator and the -200 or -300 variant designator to "772" or "773". The International Civil Aviation Organization (ICAO) aircraft type designator system adds a preceding manufacturer letter, in this case "B" for Boeing, hence "B772" or "B773". Designations may append a range identifier like "B77W" for the 777-300ER by the ICAO, and "773B" for the -300ER. 777-200 (B772) 777-200 The initial 777-200 first flew on June 12, 1994, and was first delivered to United Airlines on May 15, 1995. The competing Airbus aircraft was the A330-300. In March 2016, United Airlines shifted operations with all 19 of its -200s to exclusively domestic US routes, including flights to and from Hawaii, and added more economy class seats by shifting to a ten-abreast configuration (a pattern that matched American Airlines' reconfiguration of the type). , Boeing no longer markets the -200, as indicated by its removal from the manufacturer's price listings for 777 variants. With a 656,000 lb (298 t) MTOW and engines, it has a range with 301 passenger seats in a three-class configuration. Boeing proposed the 787-10 to replace it. The value of a new -200ER rose from US$110 million at service entry to US$130 million in 2007; a 2007 model 777 was selling for US$30 million ten years later, while the oldest ones had a value around US$5–6 million, depending on the remaining engine time. The engine can be delivered de-rated with reduced engine thrust for shorter routes to lower the MTOW, reduce purchase price and landing fees (as 777-200 specifications) but can be re-rated to full standard. 777-200LR (B77L) 777-200LR Worldliner |alt=Aircraft landing approach. Side view of twin-engine jet in flight with flaps and landing gear extended. The 777-200LR Worldliner ("LR" for Long Range), the C-market model, entered service in 2006 as one of the longest-range commercial airliners. Boeing named it Worldliner as it can connect almost any two airports in the world, although it is still subject to ETOPS restrictions. It holds the world record for the longest nonstop flight by a commercial airliner. Other new features include extended raked wingtips, redesigned main landing gear, and additional structural strengthening. The first -200LR was delivered to Pakistan International Airlines on February 26, 2006. Twelve different -200LR customers took delivery of 61 aircraft. Airlines operated 50 of the -200LR variant . The closest competing aircraft from Airbus are the discontinued A340-500HGW 777 Freighter , the largest operator of the type The 777 Freighter (777F) is an all-cargo variant which shares several features with the -200LR, including its airframe, engines, and fuel capacity. With a maximum payload of —comparable to the capacity of the Boeing 747-200F—the aircraft can fly up to 9,750 nmi (18,057 km; ) when lightly loaded, or 4,970 nmi (9,200 km; ) at maximum structural payload. The 777F includes a supernumerary area forward of the rigid cargo barrier with four business-class seats, two crew bunks, a galley, and a lavatory. The type offers improved operating economics compared to older freighters, The first 777F was delivered to Air France on February 19, 2009. With a 660,000 lb (299 t) MTOW and engines, it has a range of with 368 passengers in three-class.), Its wings have an aspect ratio of 9.0. It is powered by the GE90-115B turbofan, the world's most powerful jet engine with a maximum thrust of . Following flight testing, aerodynamic refinements have reduced fuel burn by an additional 1.4%. At , FL300, −59 °C and at a weight, it burns of fuel per hour. Its operating empty weight is . The projected operational empty weight is in airline configuration, at a weight of and FL350, total fuel flow is at , rising to at . Since its launch, the -300ER has been a primary driver of the airplane's sales past the rival A330/340 series. Its direct competitors have included the Airbus A340-600 and the A350-1000. Using two engines produces a typical operating cost advantage of around 8–9% for the -300ER over the A340-600. Several airlines have acquired the -300ER as a 747-400 replacement amid rising fuel prices given its 20% fuel burn advantage. The first 777-300ER was delivered to Air France on April 29, 2004. The -300ER is the best-selling 777 variant, with Emirates being the largest operator with 123 777-300ER in service, having surpassed the -200ER in orders in 2010 and deliveries in 2013. The 777-8 provides seating for 395 passengers and has a range of , while the 777-9 has seating for 426 passengers and a range of over . A longer 777-10X and 777X BBJ variants have also been proposed. Government and corporate government 777-200ER.|alt=Aircraft landing approach. Side view of a twin-engine jet in flight with flaps and landing gear extended. 777-300ER used as Japanese Air Force One|alt=Aircraft on the ground, with airstairs docked to the front left door. 777-300ER used for carrying Government officials including President and Prime Minister of India. Versions of the 777 have been acquired by government and private customers. The main purpose has been for VIP transport, including as an air transport for heads of state, although the aircraft has also been proposed for other military applications. • 777 Business Jet (777 VIP) – the Boeing Business Jet version of the 777 that is sold to corporate customers. Boeing has received orders for 777 VIP aircraft based on the 777-200LR and 777-300ER passenger models. The aircraft are fitted with private jet cabins by third party contractors, • KC-777 – this was a proposed tanker version of the 777. In September 2006, Boeing announced that it would produce the KC-777 if the United States Air Force (USAF) required a larger tanker than the KC-767, able to transport more cargo or personnel. In April 2007, Boeing offered its 767-based KC-767 Advanced Tanker instead of the KC-777 to replace the smaller Boeing KC-135 Stratotanker under the USAF's KC-X program. Boeing officials have described the KC-777 as suitable for the related KC-Z program to replace the wide-body McDonnell Douglas KC-10 Extender. • In 2014, the Japanese government chose to procure two 777-300ERs to serve as the official air transport for the Emperor of Japan and Prime Minister of Japan. The aircraft, operated by the Japan Air Self-Defense Force under the callsign Japanese Air Force One, entered service in 2019 and replaced two 747-400s - the 777-300ER was specifically selected by the Ministry of Defense owing to its similar capabilities to the preceding 747 pair. Besides VIP transport, the 777s are also intended for use in emergency relief missions. Turkmenistan (VIP-configured 777-200LR) and the United Arab Emirates (VIP-configured 777-200ER and 777-300ER operated by Abu Dhabi Amiri Flight). The Indian government purchased two Air India 777-300ERs and converted them for VVIP transport operated by the Indian Air Force under the callsign Air India One; they entered service in 2021 replacing the Air India-owned 747s. • In 2014, the USAF examined the possibility of adopting modified 777-300ERs or 777-9Xs to replace the Boeing 747-200 aircraft used as Air Force One. Although the USAF had preferred a four-engine aircraft, this was mainly due to precedent (existing aircraft were purchased when the 767 was just beginning to prove itself with ETOPS; decades later, the 777 and other twin jets established a comparable level of performance to quad-jet aircraft). Aftermarket freighter conversions In the 2000s, Boeing began studying the conversion of 777-200ER and -200 passenger airliners into freighters, under the name 777 BCF (Boeing Converted Freighter). The company has been in discussion with several airline customers, including FedEx Express, UPS Airlines, and GE Capital Aviation Services, to provide launch orders for a 777 BCF program. In July 2018, Boeing was studying a 777-300ER freighter conversion, targeted for the volumetric market instead of the density market served by the production 777F. New-build 777-300ERs may maintain the delivery rate at five per month, to bridge the production gap until the 777X is delivered. Within the 811 777-300ERs delivered and 33 to be delivered by October 2019, GE Capital Aviation Services (GECAS) anticipates up to 150-175 orders through 2030, with the four to five month conversion costing around $35 million. Certification and service entry was initially scheduled for late 2022. By March 2023, IAI had a backlog of over 60 orders, and completed the first flight of its prototype. The 777-300ERSF received its Supplemental Type Certificate (STC) on 1 September 2025 from both the U.S. Federal Aviation Administration (FAA) and the Civil Aviation Authority of Israel (CAAI). The IAI 777-300ER Special Freighter claims a maximum payload of , a range of , and shares the door aperture and aft position of the 777F. Kansas Modification Center claims a maximum payload of , room for 47 pallets, and a range of about at maximum payload. Unlike IAI's 777-300ERSF, which has its cargo door aft of the wing, KMC's conversion places its door in front of the wing. KMC claims this requires less structural reinforcement, which results in a lighter and more fuel-efficient aircraft. Mammoth 777-200LRMF and 777-300ERMF Mammoth Freighters launched 777-200LR and 777-300ER conversions in September 2021, dubbed the 777-200LRMF and 777-300ERMF respectively. Qatar Airways Cargo will be the launch customer for the 777-200LRMF. The first prototype flew on May 1st, 2025. The 777-300ERMF will be launched by AviaAM leasing. , the first 777-300ERMF prototype is expected to be completed by the end of 2025. Mammoth claims the 777-200LRMF will have a maximum payload of , a total volume of , and a range of at maximum payload. The 777-300ERMF claims a maximum payload of , a total volume of , and a range of at maximum payload. Experimental Boeing has used 777 aircraft in two research and development programs. The first program, the Quiet Technology Demonstrator (QTD) was run in collaboration with Rolls-Royce and General Electric to develop and validate engine intake and exhaust modifications, including the chevrons subsequently used in the 737 MAX, 747-8 and 787 series. The tests were flown in 2001 and 2005. A further program, the ecoDemonstrator series, is intended to test and develop technologies and techniques to reduce aviation's environmental impact. The program started in 2011, with the first ecoDemonstrator aircraft flying in 2012. Various airframes have been used since to test a wide variety of technologies in collaboration with a range of industrial partners. 777s have been used on three occasions as of 2024. The first of these, a 777F in 2018, performed the world's first commercial airliner flights using 100% sustainable aviation fuel (SAF). In 2022 through 2024, the testbed was a 777-200ER. ==Operators==

, the largest 777 operator, at Dubai International Airport|alt=View of airport terminal building with 10 airliners parked in a row adjacent to it. Boeing customers that have received the most 777s are Emirates, Singapore Airlines, United Airlines, ILFC, and American Airlines. The 1,000th 777 off the production line, a -300ER set to be Emirates' 102nd 777, was unveiled at a factory ceremony in March 2012. A total of 1,416 aircraft (all variants) were in airline service , with Emirates (163), United Airlines (91), Air France (70), Cathay Pacific (69), American Airlines (67), Qatar Airways (67), British Airways (58), Korean Air (53), All Nippon Airways (50), Singapore Airlines (46), and other operators with fewer aircraft of the type. The last 777-300ER to enter service did so after nearly five years in storage. Built for China Southern Airlines, it first flew in January 2020 but due to the COVID-19 pandemic, was not delivered and placed in store at Southern California Logistics Airport. It entered service with Ethiopian Airlines in December 2024 on lease from Altavair. Orders and deliveries The 777 surpassed 2,000 orders by the end of 2018. ==Accidents and incidents==

clogging the fuel-oil heat exchanger on a Rolls-Royce Trent 800 engine, from the Air Accidents Investigation Branch (AAIB) report on the British Airways Flight 38 (BA38) and Delta Air Lines Flight 18 (DL18) incidents. including a total of eight hull losses (five in-flight accidents), resulting in 542 fatalities (including three fatalities due to ground casualties), along with three hijackings. The aircraft, operated by British Airways, sustained fire damage to the lower wing panels and engine housing; it was later repaired and returned to service. The first hull loss occurred on January 17, 2008, when a 777-200ER with Rolls-Royce Trent 895 engines, flying from Beijing to London as British Airways Flight 38, crash-landed approximately short of Heathrow Airport's runway 27L and slid onto the runway's threshold. There were 47 injuries and no fatalities. The impact severely damaged the landing gear, wing roots and engines. The accident was attributed to ice crystals suspended in the aircraft's fuel clogging the fuel-oil heat exchanger (FOHE). Two other minor momentary losses of thrust with Trent 895 engines occurred later in 2008. Investigators found these were also caused by ice in the fuel clogging the FOHE. As a result, the heat exchanger was redesigned. The second hull loss occurred on July 29, 2011, when a 777-200ER scheduled to operate as EgyptAir Flight 667 suffered a cockpit fire while parked at the gate at Cairo International Airport before its departure. The aircraft was evacuated with no injuries, The aircraft sustained structural, heat and smoke damage, and was written off. A third passenger died six days later as a result of injuries sustained during the crash. These were the first fatalities in a crash involving a 777 since its entry into service in 1995. The official accident investigation concluded in June 2014 that the pilots committed 20 to 30 minor to significant errors in their final approach. Deficiencies in Asiana Airlines' pilot training and in Boeing's documentation of complex flight control systems were also cited as contributory factors. The fourth hull loss occurred on March 8, 2014, when a 777-200ER carrying 227 passengers and 12 crew, en route from Kuala Lumpur to Beijing as Malaysia Airlines Flight 370, was reported missing. Air Traffic Control's last reported coordinates for the aircraft were over the South China Sea. After the search for the aircraft began, Malaysia's prime minister, Najib Razak, announced on March 24, 2014, that after analysis of new satellite data it was now to be assumed "beyond reasonable doubt" that the aircraft had crashed in the Indian Ocean and there were no survivors. The cause remains unknown, but the Malaysian Government in January 2015, declared it an accident. US officials believe the most likely explanation to be that someone in the cockpit of Flight 370 re-programmed the aircraft's autopilot to travel south across the Indian Ocean. On July 29, 2015, an item later identified as a flaperon from the still missing aircraft was found on the island of Réunion in the western Indian Ocean, consistent with having drifted from the main search area. The fifth hull loss occurred on July 17, 2014, when a 777-200ER, bound for Kuala Lumpur from Amsterdam as Malaysia Airlines Flight 17 (MH17), was shot down by an anti-aircraft missile while flying over eastern Ukraine. All 298 people (283 passengers and 15 crew) on board were killed, making this the deadliest crash involving the Boeing 777. The incident was linked to the ongoing War in Donbas. On the basis of the Dutch Safety Board and the Joint Investigation Team official conclusions of May 2018, the governments of the Netherlands and Australia continue to hold Russia responsible for the deployment of the Buk missile system used in shooting down the airliner from territory held by pro-Russian separatists. The sixth hull loss occurred on August 3, 2016, when a 777-300 crashed while landing and caught fire at Dubai Airport at the end of its flight as Emirates Flight 521. The preliminary investigation indicated that the aircraft was attempting a landing during active wind shear conditions. The pilots initiated a go-around procedure shortly after the wheels touched-down onto the runway; however, the aircraft settled back onto the ground, apparently due to late throttle application. As the undercarriage was in the process of being retracted, the aircraft landed on its rear underbody and engine nacelles, resulting in the separation of one engine, loss of control and subsequent crash. There were no passenger casualties of the 300 people on board, but one airport fireman was killed fighting the fire. The aircraft's fuselage and right wing were irreparably damaged by the fire. The seventh hull loss occurred on November 29, 2017, when a Singapore Airlines 777-200ER experienced a fire while being towed at Singapore Changi Airport. An aircraft technician was the only occupant on board and evacuated safely. The aircraft sustained heat damage and was written off. Another fire occurred on July 22, 2020, on a 777F operating as Ethiopian Airlines Cargo Flight 3739, while on the ground at the cargo area of Shanghai Pudong International Airport. The aircraft sustained heat damage and was written off as the eighth hull loss. Media reports on legal proceedings attribute the fire to the ignition of chlorine dioxide disinfection tablets at high temperatures in a humid environment on ground. On February 20, 2021, a 777-200 operating as United Airlines Flight 328 suffered a failure of its starboard engine. The cowling and other engine parts fell over a Denver suburb. The captain declared an emergency and returned to land at the Denver airport. An immediate examination, before any formal investigation, found that two fan blades had broken off. One blade had suffered metal fatigue and may have chipped another blade, which also broke off. Boeing recommended suspending flights of all 128 operational 777s equipped with Pratt & Whitney PW4000 engines until they had been inspected. Several countries also restricted flights of PW4000-equipped 777s in their territory. On May 21, 2024, Singapore Airlines Flight 321, operated by a 777-300ER, encountered severe turbulence over Myanmar that injured 104 passengers and crew and led to the death of a passenger, who died of a suspected heart attack. ==Aircraft on display==

(ex. N7771), on display at the Pima Air & Space Museum, after 6 years in Boeing's test fleet followed by 18 years of commercial service|alt=View of twinjet aircraft parked on desert area. • The first prototype, a Boeing 777-200, B-HNL (ex. N7771), was built in 1994 and originally used by Boeing for flight testing and development. In 2000, it was sold to Cathay Pacific (as no delivery slots were available for newly-built 777s) and refurbished for passenger service. After 18 years of commercial service, B-HNL was retired in mid-2018 amid press reports that it was to be displayed at the Museum of Flight in Seattle. On September 18, 2018, Cathay Pacific and Boeing announced that B-HNL would be donated to the Pima Air & Space Museum near Tucson, Arizona, where it would be placed on permanent display. • Three retired Saudia 777-200ER aircraft, formerly registered HZ-AKG, HZ-AKK, and HZ-AKP, respectively, were transported by road from Jeddah to Riyadh in September 2024 to be displayed at the Riyadh Season exhibition. The fuselage of each aircraft was to be used as a tourist attraction featuring aviation-themed exhibits and/or dining and retail options. ==Specifications==