Wide-body aircraft

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The Airbus A380 is the world's largest and widest passenger aircraft.
Narrow-body B737 in front of a B777 wide-body

A wide-body aircraft, also known as a twin-aisle aircraft, is a jet airliner with a fuselage wide enough to accommodate two passenger aisles with seven or more seats abreast.[1] The typical fuselage diameter is 5 to 6 m (16 to 20 ft).[2] In the typical wide-body economy cabin, passengers are seated seven to ten abreast,[3] allowing a total capacity of 200 to 850[4] passengers. The largest wide-body aircraft are over 6 m (20 ft) wide, and can accommodate up to eleven passengers abreast in high-density configurations.

By comparison, a typical narrow-body airliner has a diameter of 3 to 4 m (10 to 13 ft), with a single aisle,[1][5] and seats between two and six people abreast.[6]

Wide-body aircraft were originally designed for a combination of efficiency and passenger comfort and to increase the amount of cargo space. However, airlines quickly gave in to economic factors, and reduced the extra passenger space in order to maximize revenue and profits.[7]

Wide-body aircraft are also used for the transport of commercial freight and cargo[8] and other special uses, described further below.

The biggest wide-body aircraft are known as jumbo jets due to their very large size; examples include the Boeing 747 ("jumbo jet"), Airbus A380 ("superjumbo jet"), and upcoming Boeing 777X ("mini jumbo jet").[9][10] The phrase "jumbo jet" derives from Jumbo, a circus elephant in the 19th century.[11][12]

Seven-abreast aircraft typically seat 160 to 260 passengers, eight-abreast 250 to 380, nine- and ten-abreast 350 to 480.[13]

Up to the end of 2017, nearly 8,800 wide-body airplanes had been delivered since 1969, peaking at 412 in 2015.[14]

History[edit]

Boeing 747, the first wide-body passenger aircraft, operated by Pan American World Airways

Following the success of the Boeing 707 and Douglas DC-8 in the late 1950s and early 1960s, airlines began seeking larger aircraft to meet the rising global demand for air travel. Engineers were faced with many challenges as airlines demanded more passenger seats per aircraft, longer ranges and lower operating costs.

Early jet aircraft such as the 707 and DC-8 seated passengers along either side of a single aisle, with no more than six seats per row. Larger aircraft would have to be longer, higher (such as a double deck), or wider in order to accommodate a greater number of passenger seats. Engineers realized having two decks created difficulties in meeting emergency evacuation regulations with the technology available at that time. During the 1960s, it was also believed that supersonic airliners would succeed larger, slower planes. Thus, it was believed that most subsonic aircraft would become obsolete for passenger travel and would be eventually converted to freighters. As a result, airline manufacturers opted for a wider fuselage rather than a taller one (the 747, and eventually the DC-10 and L-1011). By adding a second aisle, the wider aircraft could accommodate as many as 10 seats across, but could also be easily converted to a freighter and carry two eight-by-eight freight pallets abreast.[15]

The engineers also opted for creating "stretched" versions of the DC-8 (61, 62 and 63 models), as well as longer versions of Boeing's 707 (-320B and 320C models) and 727 (-200 model); and Douglas' DC-9 (-30, -40, and -50 models), all of which were capable of accommodating more seats than their shorter predecessor versions.

The McDonnell Douglas DC-10 (right) and MD-11 (left) wide-body trijets

The wide-body age began in 1970 with the entry into service of the first wide-body airliner, the four-engined, partial double-deck Boeing 747.[16] New trijet wide-body aircraft soon followed, including the McDonnell Douglas DC-10 and the Lockheed L-1011 TriStar. The first wide-body twinjet, the Airbus A300, entered service in 1974. This period came to be known as the "wide-body wars".[17]

After the success of the early wide-body aircraft, several subsequent designs came to market over the next two decades, including the Boeing 767 and 777, the Airbus A330 and A340, and the McDonnell Douglas MD-11. In the "jumbo" category, the capacity of the Boeing 747 was not surpassed until October 2007, when the Airbus A380 entered commercial service with the nickname "Superjumbo".[18] Both the Boeing 747 and Airbus A380 "jumbo jets" have four engines each (quad-jets), however the upcoming Boeing 777X ("mini jumbo jet") is a twinjet.[9][10]

In the mid-2000s, rising oil costs in a post-9/11 climate caused airlines to look towards newer, more fuel efficient aircraft. Two such examples are the Boeing 787 Dreamliner and Airbus A350 XWB. The proposed Comac C929 and C939 may also share this new wide-body market.

Cross-section comparison of Airbus A380 (double-deck the full length) and Boeing 747-400 (double-deck only in the front section)

The production of the large Boeing 747-8 and Airbus A380 four-engine, long-haul jets is being cut back as airlines are now preferring the smaller, more efficient A350, B787 and B777 twin-engine, long-range airliners.[19]

Design considerations[edit]

Fuselage[edit]

Airbus A300 cross-section, showing cargo, passenger, and overhead areas

Although wide-body aircraft have larger frontal areas (and thus greater form drag) than narrow-body aircraft of similar capacity, they have several advantages over their narrow-body counterparts:

  • Larger cabin space for passengers, giving a more open feeling
  • Lower ratio of surface area to volume, and thus lower drag per passenger or cargo volume. The only exception to this would be with very long narrow-body aircraft, such as the Boeing 757 and Airbus A321.
  • Twin aisles that accelerate loading, unloading, and evacuation compared to a single aisle (wide-body airliners typically have between 3.5 and 5 seats per aisle, compared to 5–6 on most narrow-body aircraft)[20]
  • Reduced overall aircraft length for a given capacity, improving ground maneuverability and reducing the risk of tail strikes.
  • Greater under-floor freight capacity
  • Better structural efficiency for larger aircraft than would be possible with a narrow-body design

British and Russian designers had proposed wide-body aircraft similar in configuration to the Vickers VC10 and Douglas DC-9, but with a wide-body fuselage. The British Three-Eleven project never left the drawing board, while the Russian Il-86 wide-body proposal eventually gave way to a more conventional wing-mounted engine design, most likely due to the inefficiencies of mounting such large engines on the aft fuselage.

Engines[edit]

Mechanic working on a Rolls Royce Trent 900 engine during testing. The Trent is a typical type of high bypass turbofan used in wide-body airliners.

As jet engine power and reliability have increased over the last decades, most of the wide-body aircraft built today have only two engines. A twinjet design is more fuel-efficient than a trijet or four-engined aircraft of similar size. The increased reliability of modern jet engines also allows aircraft to meet the ETOPS certification standard, which calculates reasonable safety margins for flights across oceans. The trijet design has been effectively dismissed due to higher maintenance and fuel costs compared to a twinjet. The vast majority of wide-body aircraft designs today have two engines, although the heaviest wide-body aircraft are built with four engines (the Airbus A380, Boeing 747 and Airbus A340).[21][22] However, the upcoming Boeing 777X ("mini jumbo jet") twinjet (777-9 variant) is approaching the capacity of the Boeing 747 while the proposed Boeing 777–10 stretch could challenge the Airbus A380.[9][10]

The Boeing 777 twinjet features the largest and most powerful[23] jet engine in the world, the General Electric GE90, which is 134 inches (3.40 m) in diameter.[24] This is almost as wide as the entire fuselage of a Boeing 737 at 148 inches (3.76 m). The GE90 series are physically the largest engines in aviation history, the fan diameter of the original series being 123 in (310 cm), and the largest variant GE90-115B has a fan diameter of 128 in (330 cm). As a result, GE90 engines can only be air freighted in assembled form by outsize cargo aircraft such as the Antonov An-124, presenting unique problems if, due to emergency diversions, a 777 were stranded in a place without the proper spare parts. If the fan is removed from the core, then the engines may be shipped on a 747 Freighter.[25]

The massive maximum takeoff weight of the Airbus A380 (560 tonnes (1,200,000 lb)) would not have been possible without the engine technology developed for the Boeing 777 (such as contra-rotating spools).[26] The Trent 900 engine pictured, used on the Airbus A380, has a fan blade diameter of 116 inches (2.95 m), only slightly smaller than the GE90 engines on the Boeing 777. An interesting design constraint of the Trent 900 engines is that they are designed to fit into a Boeing 747-400F freighter for relatively easy transport by air cargo.[27]

Interior[edit]

The interiors of aircraft, known as the aircraft cabin, have been undergoing evolution since the first passenger aircraft. Today, between one and four classes of travel are available on wide-body aircraft.

Bar and lounge areas which were once installed on wide-body aircraft have mostly disappeared, but a few have returned in first class or business class on the Airbus A340-600,[28] Boeing 777-300ER,[29] and on the Airbus A380.[30] Emirates has installed showers for first-class passengers on the A380; twenty-five minutes are allotted for use of the room, and the shower operates for a maximum of five minutes.[31][32]

Depending on how the airline configures the aircraft, the size and seat pitch of the airline seats will vary significantly.[33] For example, aircraft scheduled for shorter flights are often configured at a higher seat density than long-haul aircraft. Due to current economic pressures on the airline industry, high seating densities in the economy class cabin are likely to continue.[34]

In some of the largest single-deck wide-body aircraft, such as the Boeing 777, the extra space above the cabin is utilized for crew rest areas and galley storage.

A comparison of interior cabin widths and economy class seating layouts is shown below under wide-body specifications. Further information can be found under external links.

Wake turbulence and separation[edit]

This picture from a NASA study on wingtip vortices illustrates wake turbulence.

Aircraft are categorized by ICAO according to the wake turbulence they produce. Because wake turbulence is generally related to the weight of an aircraft, these categories are based on one of four weight categories:[35] light, medium, heavy, and super.[36]

Due to their weight, all current wide-body aircraft are categorized as "heavy", or in the case of the A380 in U.S. airspace, "super".

The wake-turbulence category also is used to guide the separation of aircraft.[37] Super- and heavy-category aircraft require greater separation behind them than those in other categories. In some countries, such as the United States, it is a requirement to suffix the aircraft's call sign with the word heavy (or super) when communicating with air traffic control in certain areas.

Special uses[edit]

A U.S. Space Shuttle mounted on a modified Boeing 747

Wide-body aircraft are used in science, research, and the military. Two specially modified Boeing 747 aircraft, the Shuttle Carrier Aircraft, were used to transport the U.S. Space Shuttle. Some wide-body aircraft are used as flying command posts by the military, such as the Boeing E-4, while the Boeing E-767 is used for Airborne Early Warning and Control. New military weapons are tested aboard wide-bodies, as in the laser weapons testing on the Boeing YAL-1. Other wide-body aircraft are used as flying research stations, such as the joint German–U.S. Stratospheric Observatory for Infrared Astronomy (SOFIA). Airbus A340,[38] Airbus A380,[39] and Boeing 747[40] four-engine wide-body aircraft are used to test new generations of aircraft engines in flight. A few aircraft have also been converted for aerial firefighting, such as the DC-10-based[41] Tanker 910 and the 747-based Evergreen Supertanker.[42]

Some wide-body aircraft are used as VIP transport. Canada uses the Airbus A310, while Russia use the Ilyushin Il-96, to transport those holding the highest offices. Germany replaced their Airbus A310 with an Airbus A340 in spring 2011. Specially-modified Boeing 747-200s (Boeing VC-25s) are used to ferry the President of the United States; when one of these aircraft is in use by the President, its call sign is Air Force One. More information can be found under Air transports of heads of state and government.

Comparison[edit]

Model produced MTOW
(tonnes)
Length inside
width
outside
width
economy seats across seat
width[a]
B767[43] 1981– 186.9 48.51–61.37 m (159.2–201.3 ft) 4.72 m (186 in) 5.03 m (198 in) 7: 2-3-2 (HD, 8: 2-4-2) 18" (16.4)
A300[44] 1974–2007 171.7 53.61–54.08 m (175.9–177.4 ft) 5.28 m (208 in) 5.64 m (222 in) 8: 2-4-2 (HD, 9: 3-3-3) 17.2" (16.4")
A310[45] 1983–1998 164 46.66 m (153.1 ft) 8: 2-4-2 17.2"
A330[46] 1994– 242 58.82–63.67 m (193.0–208.9 ft) 8: 2-4-2 (9: 3-3-3 on D7[47]) 18" (16.5")
A340[48] 1993–2011 380 59.40–75.36 m (194.9–247.2 ft) 8: 2-4-2 (9: 3-3-3) 17.8" (16.4")
B787[49] 2007– 252.7 56.72–68.28 m (186.1–224.0 ft) 5.49 m (216 in) 5.76 m (227 in) 9: 3-3-3 (8: 2-4-2 on JL[50]) 17.2"
A350[51] 2010– 268 66.61–73.59 m (218.5–241.4 ft) 5.61 m (221 in) 5.96 m (235 in) 9: 3-3-3 (10: 3-4-3 on TX[52]) 18" (16.5”)
DC-10[53] 1971–1989 259.5 51.97 m (170.5 ft) 5.69 m (224 in) 6.02 m (237 in) 9: 2-4-3, 10: 3-4-3 18", 16.5"
MD-11[54] 1990–2001 286 58.65 m (192.4 ft) 9: 2-5-2, 10: 3-4-3 18", 16.5"
L-1011[55] 1972–1985 231.3 54.17–50.05 m (177.7–164.2 ft) 5.77 m (227 in) 6.02 m (237 in) 9: 3-4-2/2-5-2, 10: 3-4-3 17.7", 16.5"
Il-86 1980–1994 206 60.21 m (197.5 ft) 5.70 m (224 in) 6.08 m (239 in) 9: 3-3-3[56] 18"
Il-96 1992- 270 55.3–63.94 m (181.4–209.8 ft)
B777[57] 1993– 351.5 63.7–73.9 m (209–242 ft) 5.86 m (231 in) 6.19 m (244 in) 9: 2-5-2, 10: 3-4-3 18.5", 17"
B777X[58] 2019– 351.5 69.8–76.7 m (229–252 ft) 5.94 m (234 in) 10: 3-4-3 17.2"
B747[59] 1968– 447.7 56.3–76.25 m (184.7–250.2 ft) 6.10 m (240 in) 6.50 m (256 in) 10: 3-4-3/9: 3-4-2 (main)
6: 3-3 (upper)
17.2"/18.5"
A380[60] 2005– 560 72.72 m (238.6 ft) 6.54 m (257 in)[b] 7.14 m (281 in) 10: 3-4-3 (11: 3-5-3 proposed[61]) (main)
8: 2-4-2 (upper)
18" (18")
  1. ^ with 2" armrests when not precised
  2. ^ upper deck: 5.80 m (228 in)

See also[edit]

References[edit]

  1. ^ a b Ginger Gorham; Ginger Todd; Susan Rice (2003). A Guide to Becoming a Travel Professional. Cengage Learning. p. 40. ISBN 9781401851774. 
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  3. ^ Doganis, Rigas (2002). Flying Off Course: The Economics of International Airlines. Routledge. p. 170. ISBN 9780415213240. 
  4. ^ 27 September 2012 (2012-09-27). "Dimensions & key data | Airbus, a leading aircraft manufacturer". Airbus.com. Retrieved 2012-10-01. 
  5. ^ "narrowbody aircraft". Retrieved 2009-03-18. 
  6. ^ Royal Aero Club (Great Britain), Royal Aero Club of the United Kingdom (1967). Flight International. IPC Transport Press Ltd. p. 552. 
  7. ^ Eric Pace (1981-05-24). "How Airline Cabins are Being Reshaped". New York Times. 
  8. ^ "Wide body cargo screening still a challenge". Impact Publications. 2008-11-18. Retrieved 2009-02-17. 
  9. ^ a b c "Boeing lands US$100B worth of orders for its new 777 mini-jumbo jet, its biggest combined haul ever | Financial Post". Business.financialpost.com. 2013-11-18. Retrieved 2014-04-27. 
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  11. ^ Henry Nicholls, "Jumbo the Elephant goes large", The Guardian (November 7, 2013).
  12. ^ Eric Partridge, Tom Dalzell, Terry Victor, The New Partridge Dictionary of Slang and Unconventional English: J-Z (2006), p. 1128.
  13. ^ Ajoy Kumar Kundu (12 April 2010). Aircraft Design. Cambridge University Press. ISBN 1139487450. 
  14. ^ Javier Irastorza Mediavilla (Feb 1, 2018). "Commercial wide-body airplanes' deliveries per year, 1969-2017". 
  15. ^ Irving, Clive (1994). Wide Body: The Making of the Boeing 747. Coronet. ISBN 0-340-59983-9. 
  16. ^ Rumerman, Judy. "The Boeing 747" Archived October 7, 2012, at the Wayback Machine., U.S. Centennial of Flight Commission. Retrieved: 30 April 2006.
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  21. ^ Note: As of 2008-11-30 published Airbus data, only a handful of Airbus A340-500 aircraft orders are still pending. See Airbus A340#Deliveries and [1]
  22. ^ Note: This fact can be viewed in the Specifications section; click arrows under MTOW to sort by weight.
  23. ^ Eisenstein, Paul. "Biggest Jet Engine." Archived 2011-08-26 at WebCite Popular Mechanics, July 2004. Retrieved: December 2, 2008.
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  27. ^ Guy Norris; Mark Wagner (2005). Airbus A380: superjumbo of the 21st century. Zenith Imprint. p. 111. ISBN 9780760322185. 
  28. ^ [2] Archived November 20, 2008, at the Wayback Machine.
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  30. ^ "A380 First Class Social Area & onboard Lounge | Emirates A380 First Class | The Emirates A380 | Our Fleet | Flying with". Emirates. 2009-06-02. Retrieved 2009-12-20. 
  31. ^ "A380 Shower Spa | Emirates A380 First Class | The Emirates A380 | Our Fleet | Flying with". Emirates. 2009-06-02. Retrieved 2009-12-20. 
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  34. ^ "Flying through a storm". Economist.com. 2008-10-22. Retrieved 2009-03-16. 
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  37. ^ [3] Archived September 5, 2009, at the Wayback Machine.
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  41. ^ "Firefighting DC-10 available to lease". Flightglobal.com. Retrieved 2009-12-20. 
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  60. ^ "A380 Airplane Characteristics for Airport Planning" (PDF). Dec 1, 2016. 
  61. ^ DOMINIC PERRY (21 March 2014). "PICTURE: to offer 11-abreast economy seats on A380". flightglobal. 

External links[edit]