Introducing the Boeing B757
The Boeing 757 is a mid-size, narrow-body twinjet airliner manufactured by Boeing Commercial Airplanes. Passenger versions of the 757 can carry between 186 and 279 passengers, and have a maximum range of 3,100 to 3,900 nautical miles (5,900 to 7,200 km) depending on variant and seating configuration. The Boeing 757 has been produced in two fuselage lengths: the original 757-200 entered service in 1983, and the stretched 757-300 entered service in 1999. Freighter versions of the 757-200, the 757-200PF and 757-200SF, have also been produced.
Launched with orders from Eastern Air Lines and British Airways in 1978, the Boeing 757 was intended to replace the previous narrow-body 727 trijet on short and medium routes. The 757 was conceived and designed in tandem with the 767, a wide-body twinjet with which it shares design features and two-crew flight decks. The operating similarities between the two aircraft allow pilots to obtain a common type rating to operate both jets, after the completion of a transition course. After its introduction, the 757 became commonly used by operators in both the United States and Europe, and particularly with mainline U.S. carriers and European charter airlines. The 757 has also been acquired for use as government, military, and VIP transport.
Production of the 757 ended on October 28, 2004 after 1,050 had been built. The final aircraft was delivered to Shanghai Airlines on November 28, 2005. A total of 1,031 Boeing 757 aircraft were in airline service in July 2008. Delta Air Lines operates the largest 757 fleet as of 2009.
Background
In the 1960s, the Boeing 727 had become the best-selling jetliner produced to date, with over 1,000 sales. The 727 was a trijet narrow-body airliner which operated short-to-medium routes, and had found particular success in the U.S. domestic airline market. By the 1970s, Boeing was considering plans to improve on the design of its most popular 727 variant, the 189-seat 727-200. Two approaches were considered: a stretched 727-300, and a new development study, code-named 7N7. Along with a parallel development effort code-named 7X7, these studies aimed to take advantage of new materials and propulsion advances in the civil aerospace industry. The 7N7 was planned as a narrow-body twinjet, while the 7X7, which eventually became the 767, was planned as a mid-size wide-body airliner. The 727-300 never received enough interest from the airlines to proceed, as the 7N7 came to the forefront of 727 replacement considerations. Airlines were particularly interested in the new engine technology, reduced weight, improved aerodynamics, and reduced operating cost promised by the 7N7 concept.
In 1978, Boeing's 7N7 studies concentrated on two variants: a 7N7-100 with seating for 160, and a 7N7-200 with capacity for over 180 seats. The 7N7 studies retained the T-tail configuration of the 727 along with its single-aisle, narrow-body layout, while adding an advanced aft-loaded wing and new engines. The narrow-body configuration was touted as offering the lowest fuel burn per passenger-kilometer of any jetliner. On August 31, 1978, the 7N7 received its first airline commitments when British Airways and Eastern Airlines announced launch orders totaling 40 aircraft for the -200 version. These orders were formally signed in March 1979, at which time Boeing formally designated its new twinjet as the 757. The shorter -100 development, which failed to attract any orders, was dropped, with its role eventually taken by the 737-300 and 737-400.
Design effort
For much of its development, the 757 retained the 727's T-tail configuration, combined with under-wing engines, but a conventional tail was ultimately adopted one year after its first airline orders. Initially, the design also retained the 727 forward fuselage and flight deck, but as the development effort progressed, the 757 moved away from shared 727 elements and incorporated more advanced structural features and systems, The 757 nose and cockpit section came to share design elements with the 767. The 757 retained the same upper-fuselage diameter as the previous Boeing 707, 727, and 737. Increases in the 757 design's maximum take-off weight (MTOW) allowed the 757 to better perform in hot and high climates.
The 757 and 767 were designed to share common flight decks and handling characteristics. The 757 was designed with similarly configured systems, shared instrumentation, avionics, and flight management systems as the 767. Due to their shared design, after a short conversion course, pilots rated in the 757 were also qualified to fly the 767 and vice versa. The 757 wing's aft-loaded design produced lift across the majority of the upper wing, instead of a narrow band as in previous designs. British Airways and Rolls-Royce initially lobbied the British aircraft industry to build 757 wings, but this did not occur.
The 757 was the first Boeing airliner launched with engines produced outside the United States, with early customers selecting the Rolls-Royce RB211. Pratt & Whitney soon offered the PW2000, launched by Delta Air Lines. General Electric offered an engine option early in the program, the CF6-32, but eventually abandoned the engine due to insufficient demand. With the -100 variant attracting little interest, the primary 757 design offered to customers consisted of the -200 model, with the choice of engine manufacturer, and either regular or longer-range fuel capacity.
Production and service
The first Boeing 757 was rolled out at Boeing's Renton, Washington facility on January 13, 1982, and completed its maiden flight on February 19 of that year. The prototype aircraft was equipped with Rolls-Royce RB211 engines, marking the first time that a foreign engine was used on a Boeing debut model. Five aircraft were used for the flight-test program, which took place over seven months for a total of 1,250 flying hours. Following testing and certification, the first 757 was delivered to launch customer Eastern Air Lines on December 22, 1982, approximately four months after the first 767 deliveries. Eastern Air Lines put the aircraft into commercial service on January 1, 1983, followed by British Airways on February 9, 1983.
The 757 is used on heavy domestic routes as well as transatlantic routes between North America and Europe. The majority of 757s are in service with U.S. carriers (64% of aircraft in service at July 2007), Delta Air Lines and American Airlines being the first and second largest customers of the type, respectively. Prior to July 2007, American Airlines was the largest operator, operating a total of 141 757s. American Airlines has retired their 757 fleet that was inherited via American's buyout of TWA, due to the fact that they use Pratt & Whitney engines rather than Rolls-Royce like most of American's 757s. United Airlines, Continental Airlines, US Airways, America West Airlines (now a part of the US Airways Group), and Northwest Airlines (now a part of Delta Air Lines) also operate large 757 fleets. The 757 is the only type of aircraft currently used by all five U.S. "legacy" airlines. The 757 is also used by holiday/charter airlines in mainly in North America and Europe.
Further developments
In the late 1990s, Boeing was considering possible variants of the 757, which for 18 years had been the only Boeing narrow-body jet not to receive a stretched variant. Rumors of a long-range -200X and stretched -300X circulated at the time, but no formal announcements had been made. In 1996, Boeing finally announced the stretched 757-300 program at the Farnborough air show. The program was intended to be the shortest development program in Boeing history, with 27 months targeted between launch and certification. The 757-300 was launched with an order for 12 aircraft from Condor Airlines. The first 757-300 was rolled out on May 31, 1998, and completed its maiden flight on August 2, 1998. Following regulatory certification in January 1999, the aircraft entered service with Condor on March 19, 1999.
While the 757 program was a resounding financial success, sales dwindled during the late 1990s, eventually forcing Boeing to cease production. The 1,050th and last 757, destined for Shanghai Airlines, rolled off the production line at Renton on October 28, 2004 and was delivered to the customer in April, 2005 after several months of storage. In the short term, the 757-200 has been succeeded by the 737-900ER, touted by Boeing as filling in the range and capacity gap previously filled by the former aircraft. In the long term, the 757 is to be succeeded by the Y1. Variants of the Boeing 787 may also take on the 757's routes.
Design
The Boeing 757 is a low-wing cantilever monoplane with a conventional tail unit with a single fin and rudder. It has two main landing gear with four wheels each and one forward nose gear. The wing is swept at 25 degrees, and the aircraft optimized for a cruising speed of Mach 0.8. For purposes of air traffic control spacing, the FAA requires greater separation behind a 757 than other large category aircraft because of their tendency to produce strong wake turbulence.
The 757-200 cockpit design, shared with the 767, uses six Rockwell Collins cathode-ray tube (CRT) screens to display electronic flight instrumentation. The displays are used for electronic flight instrumentation system (EFIS) and engine indication and crew alerting system (EICAS) information, taking over the former role of the flight engineer.
The 757-200 introduced an interior that became standard on all narrow-body Boeing aircraft (including the Boeing 737 Classics) until the release of the Next Generation 737, which introduced an updated interior borrowing elements from the Boeing 777-style interior. The 757 interior offers up to a six abreast layout (3+3) with a single center aisle. The 757 could be ordered with either four exit doors on each side, or three exit doors plus four overwing window exit doors.
Winglet upgrades
Increased fuel prices have put pressure on airlines to improve the average fuel efficiency of their fleets. American Airlines's 757-200 aircraft each burned $4,153 of jet fuel to fly from St. Louis to San Francisco in 2004; in 2008, the same quantity of fuel cost $14,676 One way to improve the efficiency of an airplane is to reduce lift-induced drag by installing winglets. Although production of the aircraft has ceased, blended winglets are available from Aviation Partners Inc. as a retrofit to increase fuel efficiency and range. Aviation Partners claims improvements of 5% on fuel efficiency and 200 nautical miles (370 km) on range. Winglets on the 757 have been approved for the 757-200 series as 757-200WL (757-200WingLets), and for the -300 series. Continental Airlines received the first modified -300 with winglets on February 3, 2009.
Source: Wikipedia, images: Boeing
