Boeing 747

The **Boeing 747** is an American wide-bouk commercial jet airliner an cargae aircraft, aften referred tae bi its oreeginal nickname, "Jumbo Jet". Its distinctive "hump" upper deck alang the forrit pairt o the aircraft haes made it ane o the maist recognisable aircraft, an it wis the first wide-bouk airplane produced. Manufacturt bi Boeing's Commercial Airplane unit in the Unitit States, the 747 wis oreeginally enveesioned tae hae 150 per cent greater capacity than the Boeing 707, a common lairge commercial aircraft o the 1960s. First flewn commercially in 1970, the 747 held the passenger capacity record for 37 year.

The fower-ingine 747 uises a dooble-deck confeeguration for pairt o its lenth an is available in passenger, frauchter an ither versions. Boeing designed the 747's hump-lik upper deck tae serve as a first–cless loonge or extra seatin, an tae allou the aircraft tae be easily convertit tae a cargae cairier bi remuivin seats an instawin a front cargae door. Boeing expectit supersonic airliners—the development o that wis annoonced in the early 1960s—tae render the 747 an ither subsonic airliners obsolete, while the demand for subsonic cargae aircraft wad remeen robust weel intae the futur. Tho the 747 wis expectit tae acome obsolete efter 400 war sauld, it exceedit creetics' expectations wi production surpassin 1,000 in 1993. Bi Januar 2018, 1,543 aircraft haed been biggit, wi 11 o the 747-8 variants remeenin on order.  , the 747 haes been involved in 60 huil losses, resultin in  fatalities.

The 747-400, the maist common variant in service, haes a heich-subsonic cruise speed o Mach 0.85–0.855 (up tae ) wi an intercontinental range o 7,260&nbsp;nautical mile (8,350&nbsp;statute mile or 13,450&nbsp;km). The 747-400 can accommodate 416 passengers in a teepical three-cless layoot, 524 passengers in a teepical twa-cless layoot, or 660 passengers in a heich-density ae-cless confeeguration. The newest version o the aircraft, the 747-8, is in production an received certification in 2011. Deliveries o the 747-8F frauchter version begoud in October 2011; deliveries o the 747-8I passenger version begoud in Mey 2012.

## Development

### Backgrund
In 1963, the Unitit States Air Force stairtit a series o study projects on a verra lairge strategic transport aircraft. Awtho the C-141 Starlifter wis bein introduced, thay believed that a muckle lairger an mair capable aircraft wis needit, especially the capability tae cairy outsized cargae that wad nae fit in ony existin aircraft. Thir studies led tae ineetial requirements for the CX-Heavy Logistics seestem (CX-HLS) in Mairch 1964 for an aircraft wi a laid capacity o  an a speed o Mach 0.75 (), an an unrefueled range o  wi a peylaid o . The peylaid bay haed tae be  wide bi  heich an  lang wi access throu duirs at the front an rear.

### Production
The 747 wis conceived while air traivel wis increasin in the 1960s. The era o commercial jet transportation, led bi the enormous popularity o the Boeing 707 an Douglas DC-8, haed revolutionised lang-distance traivel. Even afore it lost the CX-HLS contract, Boeing wis asked bi Juan Trippe, preses o Pan American World Airways (Pan Am), ane o thair maist important airline customers, tae big a passenger aircraft mair nor twice the size o the 707. In this time, airport congestion, waurened bi increasin nummers o passengers cairied on relatively smaw aircraft, becam a problem that Trippe thocht coud be addressed bi a lairger new aircraft.

In 1965, Joe Sutter wis transferred frae Boeing's 737 development team tae manage the design studies for the new airliner, awready assigned the model nummer 747. Sutter ineetiatit a design study wi Pan Am an ither airlines, tae better unnerstaund thair requirements. At the time, it wis widely thocht that the 747 wad eventually be supersedit bi supersonic transport aircraft. Boeing respondit bi designin the 747 sae that it coud be adaptit easily tae cairy fraucht an remeen in production even if sales o the passenger version declined. In the frauchter role, the clear need wis tae support the conteenerised shippin methodologies that war bein widely introduced at aboot the same time. Staundart shippin conteeners are  squerr at the front (slichtly heicher due tae attachment pynts) an available in  lenths. This meant that it wad be possible tae support a 2-wide 2-heich stack o conteeners twa or three ranks deep wi a fuselage size seemilar tae the earlier CX-HLS project.

In Apryle 1966, Pan Am ordered 25 747-100 aircraft for US$525&nbsp;million. In the ceremonial 747 contract-signin banquet in Seattle on Boeing's 50t Anniversary, Juan Trippe predictit that the 747 wad be "... a great weapon for peace, competing with intercontinental missiles for mankind's destiny". As launch customer, an acause o its early involvement afore placin a formal order, Pan Am wis able tae influence the design an development o the 747 tae an extent unmatched bi a single airline afore or syne.

### Entry intae service
On 15 Januar 1970, First Leddy o the United States Pat Nixon christened Pan Am's first 747, at Dulles Internaitional Airport (later Washington Dulles Internaitional Airport) in the presence o Pan Am chairman Najeeb Halaby.

The 747 enjoyed a fairly smuith introduction intae service, owercomin concerns that some airports wad nae be able tae accommodate an aircraft that lairge. Awtho technical problems occurred, thay war relatively minor an quickly solved. Efter the aircraft's introduction wi Pan Am, ither airlines that haed bocht the 747 tae stay competitive begoud tae put thair awn 747s intae service. Boeing estimatit that hauf o the early 747 sales war tae airlines desirin the aircraft's lang range raither nor its peylaid capacity.  While the 747 haed the lawest potential operatin cost per seat, this coud anerly be achieved whan the aircraft wis fully laidit; costs per seat increased rapidly as occupancy declined. A moderately laidit 747, ane wi anly 70 percent o its seats occupied, uised mair nor 95 percent o the fuel needit bi a fully occupied 747. Nanetheless, mony banner-carriers purchased the 747 due tae its prestige "even if it made na sense economically" tae operate. In the 1970s an 1980s, thare wis eften ower 30 regularly scheduled 747s at John F. Kennedy Internaitional Airport.

The recession o 1969-1970 greatly affectit Boeing. For the year an a hauf efter September 1970 it anerly sauld twa 747s in the warld, an did nae sell ony tae an American carrier for awmaist three years. Whan economic problems in the US an ither kintras efter the 1973 ile creesis led tae reduced passenger traffeck, several airlines foond thay did nae hae eneuch passengers tae flee the 747 economically, an thay replaced them wi the smawer an recently introduced McDonnell Douglas DC-10 an Lockheed L-1011 TriStar trijet wide bouks (an later the 767 an A300/A310 twinjets). Haein tried replacin coach seats on its 747s wi pianae baurs in an attempt tae attract mair customers, American Airlines eventually relegatit its 747s tae cargo service an in 1983 exchynged them wi Pan Am for smawer aircraft; Delta Air Lines an aw remuived its 747s frae service efter several years. Later, Delta acquired 747s again in 2008 as pairt o its merger wi Northwest Airlines, awtho it reteert the 747-400 fleet in December 2017.

Internaitional flichts bipassin tradeetional hub airports an laundin at smawer ceeties becam mair common ootthrou the 1980s, sicweys erodin the 747's oreeginal mercat. Mony internaitional cairiers conteena'd tae uise the 747 on Paceefic routes. In Japan, 747s on domestic routes war confeegurt tae cairy nearly the maximum passenger capacity.

## Design

The Boeing 747 is a lairge, wide-bouk (twa-aisle) airliner wi fower weeng-mounted engines. Its weengs hae a heich sweep angle o 37.5 degrees for a fest, efficient cruise o Mach&nbsp;0.84 tae 0.88, dependin on the variant. The sweep an aw reduces the weengspan, allouin the 747 tae uise existin hangars. Its seatin capacity is ower 366 wi a 3–4–3 seat arrangement (a cross section o 3 seats, an aisle, 4 seats, anither aisle, an 3 seats) in economy cless an a 2–3–2 layout in first cless on the main deck. The upper deck haes a 3–3 seat arrangement in economy cless an a 2–2 layoot in first cless.

Raised abuin the main deck, the cockpit creauts a hump. This raised cockpit allous front laidin o cargo on fraucht variants. The upper deck ahint the cockpit provides space for a lounge an/or extra seatin. The "stretched upper deck" becam available as an alternative on the 747-100B variant an later as staundart beginnin on the 747-300. The upper deck wis stretched mair on the 747-8. The 747 cockpit ruif section an aw haes an escape hatch frae that crew can exit in the events o an emergency if thay canna dae sae throu the cabin.

The 747's maximum takaff wecht ranges frae 333,400&nbsp;kg (735,000&nbsp;poonds) for the 439,985&nbsp;kg (-100 tae 970,000&nbsp;lb) for the -8. Its range haes increased frae 5,300&nbsp;nautical miles (6,100&nbsp;mi, 9,800&nbsp;km) on the -100 tae 8,000&nbsp;nmi (9,200&nbsp;mi, 14,815&nbsp;km) on the -8I.

The 747 haes redundant structurs alang wi fower redundant hydraulic seestems an fower main laundin gears ilk wi fower wheels; thir provide a guid spreid o support on the grund an safety in case o tyre blaw-oots. The main gear are redundant sae that laundin can be performed on twa opponin laundin gears if the ithers are nae functionin properly. The 747 an aw haes split control surfaces an wis designed wi sophisticatit treeple-slottit flaps that minimise laundin speeds an allou the 747 tae uise staundart-lenth runweys.

For transportation o spare ingines, the 747 can accommodate a non-functionin fift-pod ingine unner the aircraft's port weeng atween the inner functionin ingine an the fuselage. This fift ingine munt pynt is an aw uised bi Virgin Orbit's LauncherOne programme. Virgin Orbit's 747-400, dubbed Cosmic Girl, cairies the orbital-cless racket tae cruise altitude, whaur the racket is deployed an then cairies its smaw satellite peylaid the rest o the wey tae space.

## Accidents an incidents
The 747 haes been involved in 146 aviation accidents an incidents, includin 61 accidents an huil losses that resultit in  fatalities.  The last crash wis Turkish Airlines Flicht 6491 in Januar 2017. Thare war an aw 24 daiths in 32 aircraft hijackins, sic as Pan Am Flight 73 whaur a Boeing 747-121 wis hijacked bi fower terrorists an resultit in 20 daiths.

Few crashes hae been attributit tae design flaws o the 747. The Tenerife airport disaster resultit frae pilot error an communications failyie, while the Japan Airlines Flight 123 an China Airlines Flight 611 crashes stemmed frae improper aircraft repair. United Airlines Flight 811, that suffered an explosive decompression mid-flicht on 24 Februar 1989, led the National Transportation Safety Board (NTSB) tae issue a recommendation that 747-200 cargo duirs seemilar tae thae on the Flicht 811 aircraft be modifee'd. Korean Air Lines Flicht 007 wis shot doun bi a Soviet fechter aircraft in 1983 efter it haed strayed intae Soviet territory, causin U.S. Preses Ronald Reagan tae authorise the then-strictly militar global poseetionin seestem (GPS) for ceevilian uise.

Accidents due tae design deficiencies includit TWA Flight 800, whaur a 747-100 explodit in mid-air on 17 Julie 1996, probably due tae sparkin electricity weirs inside the fuel tank; this findin led the FAA tae propone a rule requirin installation o an inertin seestem in the centre fuel tank o maist lairge aircraft that wis adoptit in Julie 2008, efter years o resairch intae solutions.  At the time, the new saufty seestem wis expectit tae cost US$100,000 tae $450,000 per aircraft an wecht approximately . El Al Flicht 1862 crashed efter the fuse pins for an ingine breuk aff shortly efter tak-aff due tae metal fatigue. Insteid o drappin awey frae the wing, the ingine knocked aff the adjacent ingine an damaged the weeng.

## Specifications

## References