Boeing 747

Boeing 747
A Pan Am 747-100 in white and blue livery during final approach with its landing gear extended. The aircraft is N732PA, the third 747 built and an aircraft that was used in the 747 flight test program.
Boeing 747-100 of Pan American World Airways, the 747's launch customer, in September 1978
RoleWide-body jet airliner
National originUnited States
ManufacturerBoeing Commercial Airplanes
First flightFebruary 9, 1969[1]
IntroductionJanuary 22, 1970 with Pan American World Airways[2][3]
StatusIn service
Primary usersBritish Airways
Lufthansa
Korean Air
Atlas Air
Produced1968–present
Number built1,548 (of which 1,546 delivered to customers) as of July 2018[4]
Program costUS$1 billion at roll-out (1968)[5]
7.0 billion today
Unit cost
747-100: US$24 million (1972)[6]
747-200: US$39 million (1976)
747-300: US$83 million (1982)
VariantsBoeing 747SP
Boeing 747-400
Boeing 747-8
Boeing VC-25
Boeing E-4
Developed intoBoeing YAL-1
Boeing Dreamlifter

The Boeing 747 is an American wide-body commercial jet airliner and cargo aircraft, often referred to by its original nickname, "Jumbo Jet". Its distinctive hump upper deck along the forward part of the aircraft has made it one of the most recognizable aircraft,[7] and it was the first wide-body airplane produced. Manufactured by Boeing's Commercial Airplane unit in the United States, the 747 was originally envisioned to have 150 percent greater capacity than the Boeing 707,[8] a common large commercial aircraft of the 1960s. First flown commercially in 1970, the 747 held the passenger capacity record for 37 years.[9]

The four-engine 747 uses a double-deck configuration for part of its length and is available in passenger, freighter and other versions. Boeing designed the 747's hump-like upper deck to serve as a first–class lounge or extra seating, and to allow the aircraft to be easily converted to a cargo carrier by removing seats and installing a front cargo door. Boeing expected supersonic airliners—the development of which was announced in the early 1960s—to render the 747 and other subsonic airliners obsolete, while the demand for subsonic cargo aircraft would remain robust well into the future.[10] Though the 747 was expected to become obsolete after 400 were sold,[11] it exceeded critics' expectations with production surpassing 1,000 in 1993.[12] By July 2018, 1,546 aircraft had been built, with 22 of the 747-8 variants remaining on order.[4] As of January 2017, the 747 has been involved in 60 hull losses, resulting in 3,722 fatalities.[13]

The 747-400, the most common variant in service, has a high-subsonic cruise speed of Mach 0.85–0.855 (up to 570 mph or 920 km/h) with an intercontinental range of 7,260 nautical miles (8,350 statute miles or 13,450 km).[14] The 747-400 can accommodate 416 passengers in a typical three-class layout, 524 passengers in a typical two-class layout, or 660 passengers in a high–density one-class configuration.[15] The newest version of the aircraft, the 747-8, is in production and received certification in 2011. Deliveries of the 747-8F freighter version began in October 2011; deliveries of the 747-8I passenger version began in May 2012.

Development

Background

In 1963, the United States Air Force started a series of study projects on a very large strategic transport aircraft. Although the C-141 Starlifter was being introduced, they believed that a much larger and more capable aircraft was needed, especially the capability to carry outsized cargo that would not fit in any existing aircraft. These studies led to initial requirements for the CX-Heavy Logistics System (CX-HLS) in March 1964 for an aircraft with a load capacity of 180,000 pounds (81,600 kg) and a speed of Mach 0.75 (500 mph or 800 km/h), and an unrefueled range of 5,000 nautical miles (9,300 km) with a payload of 115,000 pounds (52,200 kg). The payload bay had to be 17 feet (5.18 m) wide by 13.5 feet (4.11 m) high and 100 feet (30 m) long with access through doors at the front and rear.[16]

Featuring only four engines, the design also required new engine designs with greatly increased power and better fuel economy. In May 1964, airframe proposals arrived from Boeing, Douglas, General Dynamics, Lockheed, and Martin Marietta; engine proposals were submitted by General Electric, Curtiss-Wright, and Pratt & Whitney. After a downselect, Boeing, Douglas, and Lockheed were given additional study contracts for the airframe, along with General Electric and Pratt & Whitney for the engines.[16]

All three of the airframe proposals shared a number of features. As the CX-HLS needed to be able to be loaded from the front, a door had to be included where the cockpit usually was. All of the companies solved this problem by moving the cockpit above the cargo area; Douglas had a small "pod" just forward and above the wing, Lockheed used a long "spine" running the length of the aircraft with the wing spar passing through it, while Boeing blended the two, with a longer pod that ran from just behind the nose to just behind the wing.[17][18] In 1965 Lockheed's aircraft design and General Electric's engine design were selected for the new C-5 Galaxy transport, which was the largest military aircraft in the world at the time.[16] The nose door and raised cockpit concepts would be carried over to the design of the 747.[19]

Airliner proposal

The 747 was conceived while air travel was increasing in the 1960s.[20] The era of commercial jet transportation, led by the enormous popularity of the Boeing 707 and Douglas DC-8, had revolutionized long-distance travel.[20][21] Even before it lost the CX-HLS contract, Boeing was asked by Juan Trippe, president of Pan American World Airways (Pan Am), one of their most important airline customers, to build a passenger aircraft more than twice the size of the 707. During this time, airport congestion, worsened by increasing numbers of passengers carried on relatively small aircraft, became a problem that Trippe thought could be addressed by a larger new aircraft.[22]

In 1965, Joe Sutter was transferred from Boeing's 737 development team to manage the design studies for the new airliner, already assigned the model number 747.[23] Sutter initiated a design study with Pan Am and other airlines, to better understand their requirements. At the time, it was widely thought that the 747 would eventually be superseded by supersonic transport aircraft.[24] Boeing responded by designing the 747 so that it could be adapted easily to carry freight and remain in production even if sales of the passenger version declined. In the freighter role, the clear need was to support the containerized shipping methodologies that were being widely introduced at about the same time. Standard containers are 8 ft (2.4 m) square at the front (slightly higher due to attachment points) and available in 20 and 40 ft (6.1 and 12 m) lengths. This meant that it would be possible to support a 2-wide 2-high stack of containers two or three ranks deep with a fuselage size similar to the earlier CX-HLS project.

 A view of an early-production 747 cockpit
An Iran Air 747-200, showing the early-production 747 cockpit, located on the upper deck

In April 1966, Pan Am ordered 25 747-100 aircraft for US$525 million. During the ceremonial 747 contract-signing banquet in Seattle on Boeing's 50th Anniversary, Juan Trippe predicted that the 747 would be "... a great weapon for peace, competing with intercontinental missiles for mankind's destiny".[25] As launch customer,[1][26] and because of its early involvement before placing a formal order, Pan Am was able to influence the design and development of the 747 to an extent unmatched by a single airline before or since.[27]

Design effort

Ultimately, the high-winged CX-HLS Boeing design was not used for the 747, although technologies developed for their bid had an influence.[28] The original design included a full-length double-deck fuselage with eight-across seating and two aisles on the lower deck and seven-across seating and two aisles on the upper deck.[29][30] However, concern over evacuation routes and limited cargo-carrying capability caused this idea to be scrapped in early 1966 in favor of a wider single deck design.[1] The cockpit was, therefore, placed on a shortened upper deck so that a freight-loading door could be included in the nose cone; this design feature produced the 747's distinctive "bulge".[31] In early models it was not clear what to do with the small space in the pod behind the cockpit, and this was initially specified as a "lounge" area with no permanent seating.[32] (A different configuration that had been considered in order to keep the flight deck out of the way for freight loading had the pilots below the passengers, and was dubbed the "anteater".)[33]

The Pratt & Whitney JT9D turbofan suspended under the wing pylon of the 747 prototype. It is stripped of its outer casing, revealing the engine's core at The Museum of Flight in Seattle, WA
The Pratt & Whitney JT9D high-bypass turbofan engine was developed for the 747.

One of the principal technologies that enabled an aircraft as large as the 747 to be drawn up was the high-bypass turbofan engine.[34] The engine technology was thought to be capable of delivering double the power of the earlier turbojets while consuming a third less fuel. General Electric had pioneered the concept but was committed to developing the engine for the C-5 Galaxy and did not enter the commercial market until later.[35][36] Pratt & Whitney was also working on the same principle and, by late 1966, Boeing, Pan Am and Pratt & Whitney agreed to develop a new engine, designated the JT9D to power the 747.[36]

The project was designed with a new methodology called fault tree analysis, which allowed the effects of a failure of a single part to be studied to determine its impact on other systems.[1] To address concerns about safety and flyability, the 747's design included structural redundancy, redundant hydraulic systems, quadruple main landing gear and dual control surfaces.[37] Additionally, some of the most advanced high-lift devices used in the industry were included in the new design, to allow it to operate from existing airports. These included slats running almost the entire length of the wing, as well as complex three-part slotted flaps along the trailing edge of the wing.[38] The wing's complex three-part flaps increase wing area by 21 percent and lift by 90 percent when fully deployed compared to their non-deployed configuration.[39]

Boeing agreed to deliver the first 747 to Pan Am by the end of 1969. The delivery date left 28 months to design the aircraft, which was two-thirds of the normal time.[40] The schedule was so fast-paced that the people who worked on it were given the nickname "The Incredibles".[41] Developing the aircraft was such a technical and financial challenge that management was said to have "bet the company" when it started the project.[1]

Production plant

Airplane assembly hall, featuring heavy machinery. Large cylindrical airplane sections and wings are readied for mating with other major components. Above are the cranes which ferry heavy and outsize parts of the 747.
747 final assembly at the Boeing Everett Factory

As Boeing did not have a plant large enough to assemble the giant airliner, they chose to build a new plant. The company considered locations in about 50 cities,[42] and eventually decided to build the new plant some 30 miles (50 km) north of Seattle on a site adjoining a military base at Paine Field near Everett, Washington.[43] It bought the 780-acre (320 ha) site in June 1966.[44]

Developing the 747 had been a major challenge, and building its assembly plant was also a huge undertaking. Boeing president William M. Allen asked Malcolm T. Stamper, then head of the company's turbine division, to oversee construction of the Everett factory and to start production of the 747.[45] To level the site, more than four million cubic yards (three million cubic meters) of earth had to be moved.[46] Time was so short that the 747's full-scale mock-up was built before the factory roof above it was finished.[47] The plant is the largest building by volume ever built, and has been substantially expanded several times to permit construction of other models of Boeing wide-body commercial jets.[43]

Development and testing

The prototype 747 was first displayed to the public on September 30, 1968.

Before the first 747 was fully assembled, testing began on many components and systems. One important test involved the evacuation of 560 volunteers from a cabin mock-up via the aircraft's emergency chutes. The first full-scale evacuation took two and a half minutes instead of the maximum of 90 seconds mandated by the Federal Aviation Administration (FAA), and several volunteers were injured. Subsequent test evacuations achieved the 90-second goal but caused more injuries. Most problematic was evacuation from the aircraft's upper deck; instead of using a conventional slide, volunteer passengers escaped by using a harness attached to a reel.[48] Tests also involved taxiing such a large aircraft. Boeing built an unusual training device known as "Waddell's Wagon" (named for a 747 test pilot, Jack Waddell) that consisted of a mock-up cockpit mounted on the roof of a truck. While the first 747s were still being built, the device allowed pilots to practice taxi maneuvers from a high upper-deck position.[49]

On September 30, 1968, the first 747 was rolled out of the Everett assembly building before the world's press and representatives of the 26 airlines that had ordered the airliner.[50] Over the following months, preparations were made for the first flight, which took place on February 9, 1969, with test pilots Jack Waddell and Brien Wygle at the controls[51][52] and Jess Wallick at the flight engineer's station. Despite a minor problem with one of the flaps, the flight confirmed that the 747 handled extremely well. The 747 was found to be largely immune to "Dutch roll", a phenomenon that had been a major hazard to the early swept-wing jets.[53]

 A view of the 747's four main landing gear, each with four wheels
Closeup of the prototype 747's 16-wheel main landing gear

During later stages of the flight test program, flutter testing showed that the wings suffered oscillation under certain conditions. This difficulty was partly solved by reducing the stiffness of some wing components. However, a particularly severe high-speed flutter problem was solved only by inserting depleted uranium counterweights as ballast in the outboard engine nacelles of the early 747s.[54] This measure caused anxiety when these aircraft crashed, for example El Al Flight 1862 at Amsterdam in 1992 with 282 kilograms (622 lb) of uranium in the tailplane (horizontal stabilizer).[55][56]

The flight test program was hampered by problems with the 747's JT9D engines. Difficulties included engine stalls caused by rapid throttle movements and distortion of the turbine casings after a short period of service.[57] The problems delayed 747 deliveries for several months; up to 20 aircraft at the Everett plant were stranded while awaiting engine installation.[58] The program was further delayed when one of the five test aircraft suffered serious damage during a landing attempt at Renton Municipal Airport, site of the company's Renton factory. On December 13, 1969 a test aircraft was being taken to have test equipment removed and a cabin installed when pilot Ralph C. Cokely undershot the airport's short runway. The 747's right, outer landing gear was torn off and two engine nacelles were damaged.[59][60] However, these difficulties did not prevent Boeing from taking a test aircraft to the 28th Paris Air Show in mid-1969, where it was displayed to the public for the first time.[61] The 747 received its FAA airworthiness certificate in December 1969, clearing it for introduction into service.[62]

First Lady Pat Nixon ushered in the era of jumbo jets by christening the first commercial 747 at a ceremony at Dulles International Airport on January 15, 1970 (top); the First Lady then climbed aboard and visited the cockpit (below).

The huge cost of developing the 747 and building the Everett factory meant that Boeing had to borrow heavily from a banking syndicate. During the final months before delivery of the first aircraft, the company had to repeatedly request additional funding to complete the project. Had this been refused, Boeing's survival would have been threatened.[26][63] The firm's debt exceeded $2 billion, with the $1.2 billion owed to the banks setting a record for all companies. Allen later said, "It was really too large a project for us."[64] Ultimately, the gamble succeeded, and Boeing held a monopoly in very large passenger aircraft production for many years.[65]

Entry into service

On January 15, 1970, First Lady of the United States Pat Nixon christened Pan Am's first 747, at Dulles International Airport (later Washington Dulles International Airport) in the presence of Pan Am chairman Najeeb Halaby. Instead of champagne, red, white, and blue water was sprayed on the aircraft. The 747 entered service on January 22, 1970, on Pan Am's New York–London route;[66] the flight had been planned for the evening of January 21, but engine overheating made the original aircraft unusable. Finding a substitute delayed the flight by more than six hours to the following day when Clipper Victor was used.[2]

 A helical staircase on 747-100s and -200s that leads to the upper deck
On the 747-100 and 747-200, a spiral staircase connected the main and upper decks. Previously, Boeing used a spiral staircase in its Model 377 Stratocruiser back in 1946.

The 747 enjoyed a fairly smooth introduction into service, overcoming concerns that some airports would not be able to accommodate an aircraft that large.[67] Although technical problems occurred, they were relatively minor and quickly solved.[68] After the aircraft's introduction with Pan Am, other airlines that had bought the 747 to stay competitive began to put their own 747s into service.[69] Boeing estimated that half of the early 747 sales were to airlines desiring the aircraft's long range rather than its payload capacity.[70][71] While the 747 had the lowest potential operating cost per seat, this could only be achieved when the aircraft was fully loaded; costs per seat increased rapidly as occupancy declined. A moderately loaded 747, one with only 70 percent of its seats occupied, used more than 95 percent of the fuel needed by a fully occupied 747.[72] Nonetheless, many flag-carriers purchased the 747 due to its prestige "even if it made no sense economically" to operate. During the 1970s and 1980s, there was often over 30 regularly scheduled 747s at John F. Kennedy International Airport.[73]

The recession of 1969-1970 greatly affected Boeing. For the year and a half after September 1970 it only sold two 747s in the world, and did not sell any to an American carrier for almost three years.[64] When economic problems in the United States and other countries after the 1973 oil crisis led to reduced passenger traffic, several airlines found they did not have enough passengers to fly the 747 economically, and they replaced them with the smaller and recently introduced McDonnell Douglas DC-10 and Lockheed L-1011 TriStar trijet wide bodies[74] (and later the 767 and A300/A310 twinjets). Having tried replacing coach seats on its 747s with piano bars in an attempt to attract more customers, American Airlines eventually relegated its 747s to cargo service and in 1983 exchanged them with Pan Am for smaller aircraft;[75] Delta Air Lines also removed its 747s from service after several years.[76] Later, Delta acquired 747s again in 2008 as part of its merger with Northwest Airlines, although it retired the 747-400 fleet in December 2017.[77]

 A forward-looking view in the stretched upper deck cabin of later 747s
Later 747 models featured a stretched upper deck.

International flights that bypassed traditional hub airports and landed at smaller cities became more common throughout the 1980s, and this eroded the 747's original market.[78] However, many international carriers continued to use the 747 on Pacific routes.[79] In Japan, 747s on domestic routes were configured to carry close to the maximum passenger capacity.[80]

Improved 747 versions

After the initial 747-100, Boeing developed the -100B, a higher maximum takeoff weight (MTOW) variant, and the -100SR (Short Range), with higher passenger capacity.[81] Increased maximum takeoff weight allows aircraft to carry more fuel and have longer range.[82] The -200 model followed in 1971, featuring more powerful engines and a higher MTOW. Passenger, freighter and combination passenger-freighter versions of the -200 were produced.[81] The shortened 747SP (special performance) with a longer range was also developed, and entered service in 1976.[83]

The 747 line was further developed with the launch of the 747-300 in 1980. The 300 series resulted from Boeing studies to increase the seating capacity of the 747, during which modifications such as fuselage plugs and extending the upper deck over the entire length of the fuselage were rejected. The first 747-300, completed in 1983, included a stretched upper deck, increased cruise speed, and increased seating capacity. The -300 variant was previously designated 747SUD for stretched upper deck, then 747-200 SUD,[84] followed by 747EUD, before the 747-300 designation was used.[85] Passenger, short range and combination freighter-passenger versions of the 300 series were produced.[81]

 An Air New Zealand 747-400 with its landing gear down and flaps down.  The aircraft is mostly white and blue aircraft and in-flight against a blue sky. On each of the two wings are two engines.
The 747-400 entered service in 1989, with Air New Zealand among the original operators of the type.

In 1985, development of the longer range 747-400 began.[86] The variant had a new glass cockpit, which allowed for a cockpit crew of two instead of three,[87] new engines, lighter construction materials, and a redesigned interior. Development cost soared, and production delays occurred as new technologies were incorporated at the request of airlines. Insufficient workforce experience and reliance on overtime contributed to early production problems on the 747-400.[1] The -400 entered service in 1989.[88]

In 1991, a record-breaking 1,087 passengers were airlifted aboard a 747 to Israel as part of Operation Solomon.[89] The 747 remained the heaviest commercial aircraft in regular service until the debut of the Antonov An-124 Ruslan in 1982; variants of the 747-400 would surpass the An-124's weight in 2000. The Antonov An-225 Mriya cargo transport, which debuted in 1988, remains the world's largest aircraft by several measures (including the most accepted measures of maximum takeoff weight and length); one aircraft has been completed and is in service as of 2017. The Hughes H-4 Hercules is the largest aircraft by wingspan, but it only completed a single flight.[90]

Further developments

Interior view. Seats are separated by two aisles, in 3-4-3 configuration. A TV is positioned towards the front of aircraft.
747-400 main deck economy class seating in 3-4-3 layout

Since the arrival of the 747-400, several stretching schemes for the 747 have been proposed. Boeing announced the larger 747-500X and -600X preliminary designs in 1996.[91] The new variants would have cost more than US$5 billion to develop,[91] and interest was not sufficient to launch the program.[92] In 2000, Boeing offered the more modest 747X and 747X stretch derivatives as alternatives to the Airbus A3XX. However, the 747X family was unable to attract enough interest to enter production. A year later, Boeing switched from the 747X studies to pursue the Sonic Cruiser,[93] and after the Sonic Cruiser program was put on hold, the 787 Dreamliner.[94] Some of the ideas developed for the 747X were used on the 747-400ER, a longer range variant of the 747-400.[95]

After several variants were proposed but later abandoned, some industry observers became skeptical of new aircraft proposals from Boeing.[96] However, in early 2004, Boeing announced tentative plans for the 747 Advanced that were eventually adopted. Similar in nature to the 747-X, the stretched 747 Advanced used technology from the 787 to modernize the design and its systems. The 747 remained the largest passenger airliner in service until the Airbus A380 began airline service in 2007.[97]

On November 14, 2005, Boeing announced it was launching the 747 Advanced as the Boeing 747-8.[98] The last 747-400s were completed in 2009.[99] As of 2011, most orders of the 747-8 have been for the freighter variant. On February 8, 2010, the 747-8 Freighter made its maiden flight.[100] The first delivery of the 747-8 went to Cargolux in 2011.[101][102] The 1,500th produced Boeing 747 was delivered in June 2014.[103]

In January 2016, Boeing stated it was reducing 747-8 production to six a year beginning in September 2016, incurring a $569 million post-tax charge against its fourth-quarter 2015 profits. At the end of 2015, the company had 20 orders outstanding.[104][105] On January 29, 2016, Boeing announced that it had begun the preliminary work on the modifications to a commercial 747-8 for the next Air Force One Presidential aircraft, expected to be operational by 2020.[106]

On July 12, 2016, Boeing announced that it had finalized terms of acquisition with Volga-Dnepr Group for 20 747-8 freighters, valued at $7.58 billion at list prices. Four aircraft were delivered beginning in 2012. Volga-Dnepr Group is the parent of three major Russian air-freight carriers – Volga-Dnepr Airlines, AirBridgeCargo Airlines and Atran Airlines. The new 747-8 freighters will replace AirBridgeCargo's current 747-400 aircraft and expand the airline's fleet and will be acquired through a mix of direct purchases and leasing over the next six years, Boeing said.[107]

On July 27, 2016, in its quarterly report to the Securities and Exchange Commission, Boeing discussed the potential termination of 747 production due to insufficient demand and market for the aircraft.[108] With a firm order backlog of 21 aircraft and a production rate of six per year, program accounting has been reduced to 1,555 aircraft, and the 747 line could be closed in the third quarter of 2019.[109] In October 2016, UPS Airlines ordered 14 -8Fs to add capacity, along with 14 options, which it took in February 2018 bringing the total ordered to 28[110] and increases the backlog to 25 – including some to refractory airlines – with deliveries scheduled through 2022.[111]

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