Friday, March 14, 2008

Boieng 777

Boieng 777
The Boeing 777 is an American long-range, wide-body twin-engine airliner built by Boeing Commercial Airplanes. The world's largest twinjet and commonly referred to as the Triple Seven, it can carry between 283 and 368 passengers in a three-class configuration and has a range from 5,235 to 9,450 nautical miles (9,695 to 17,500 km). Distinguishing features of the 777 include the six wheels on each main landing gear, its circular fuselage cross section, the largest diameter turbofan engines of any aircraft, the pronounced "neck" aft of the cockpit, and the blade-like tail cone.
Singapore Airlines is the largest operator of the Boeing 777 family with 69 in service (46 are the 777-200ER variant, 12 are 777-300s, and 11 are 777-300ERs with 8 on firm order and 13 more on option). As of February 2008, 53 customers have placed orders totaling 1,050 777s.
Direct market competitors to the 777 are the Airbus A330-300, A340, and some models of the A350 XWB, which is currently under development. The 777 may eventually be replaced by a new product family, the Boeing Y3, which would draw upon technologies from the 787. The Y3 may also replace the Boeing 747 series.
Design phase the mid-1980s Boeing produced proposals for an enlarged 767, dubbed 767X. There were also a number of in-house designations for proposals, of which the 763-246 was one internal designation that was mentioned in public. The 767X had a longer fuselage and larger wings than the existing 767, and seated about 340 passengers with a maximum range of 7,300 nautical miles (13,500 kilometers). The airlines were unimpressed with the 767X: they wanted short to intercontinental range capability, a bigger cabin cross section, a fully flexible cabin configuration and an operating cost lower than any 767 stretch. By 1988 Boeing realized that the only answer was a new design, the 777 twinjet.
Designing of the 777 was different from previous Boeing jetliners. For the first time, eight major airlines (Cathay Pacific, American, Delta, ANA, BA, JAL, Qantas, and United) had a role in the development of the plane as part of a "Working Together" collaborative model employed for the 777 project.At the first "Working Together" meeting in January 1990, a 23-page questionnaire was distributed to the airlines, asking each what it wanted in the new design. By March 1990 a basic design for the 767X had been decided upon; a cabin cross-section close to the 747s, 325 passengers, fly-by-wire controls, glass cockpit, flexible interior, and 10% better seat-mile costs than the A330 and MD-11. ETOPS was also a priority for United Airlines.
All software, whether produced internally to Boeing or externally, was to be written in Ada. The bulk of the work was undertaken by Honeywell who developed a Airplane Information Management System (AIMS). This handles the flight and navigation displays, systems monitoring and data acquisition (eg flight data acquisition).
United's replacement program for its aging DC-10s became a focus for Boeing's designs. The new aircraft needed to be capable for flying three different routes; Chicago to Hawaii, Chicago to Europe and non-stop from the hot and high Denver to Hawaii.
In October 1990, United Airlines became the launch customer when it placed an order for 34 Pratt & Whitney-powered 777s with options on a further 34. Production of the first aircraft began in January 1993 at Boeing's Everett plant near Seattle. In the same month, the 767X was officially renamed the 777, and a team of United 777 developers joined other airline teams and the Boeing team at the Boeing Everett Factory. Divided into 240 design teams of up to 40 members, working on individual components of the aircraft, almost 1,500 design issues were addressed.
The 777 was the first commercial aircraft to be designed entirely on computer. Everything was created on a 3D CAD software system known as CATIA, sourced from Dassault Systemes. This allowed a virtual 777 to be assembled, in simulation, to check for interferences and to verify proper fit of the many thousands of parts before costly physical prototypes were manufactured. Boeing was not totally convinced of the abilities of the program, and built a mock-up of the nose section to test the results. It was so successful that all further mock-ups were canceled.

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