The 777 is designed for both intercontinental and transcontinental routes and is targeted primarily at the Pacific rim market. The design is typical of previous Boeing airliners except it is equipped with only two engines, unlike the transcontinental and. To achieve flight certification for the twin-engine layout on long flight over oceans, Boeing had to ensure new levels of reliability in engines, avionics, and the fly-by-wire control system as well as the ability to maintain level flight for three hours even with one engine inoperative. Like the 747, the 777 includes three powerplant options depending on airline preference, and these air-breathing engines are the most powerful ever fitted to any aircraft. To give some idea of the size of the 777, the engine nacelles are nearly as wide as the fuselage of the. However, some airlines requested the large airliner be able to use passenger gates designed for the and smaller aircraft, so the outer wing panels are designed to fold upward on some models. Five major variants of the 777 have been delivered to date. Base models are the 777-200 and stretched 777-300, and extended and long range models and a freighter have also been developed. Nearly 800 aircraft had been built by July 2009 out of more than 1,100 ordered. Glasgow: Harper Collins Publishers, 1996, p. The Complete Encyclopedia of World Aircraft. The Encyclopedia of Civil Aircraft. San Diego, CA: Thunder Bay Press, 1999, p. Jane's Aircraft Recognition Guide, 2nd ed. London: Harper Collins Publishers, 1999, p. London: Brassey's, 1996, p. London: Brassey's, 1999, p.
