The Boeing 737 is a popular short-to-medium range commercial passenger jet aircraft continuously manufactured by Boeing Commercial Airplanes since 1967. Over 5,000 have been sold since its introduction in 1967, more than any other commercial airliner, and more than Airbus' entire product line.
The 737 was born out of Boeing's need to field a competitor in the short-range, small capacity jetliner market which had been opened up by the BAC 1-11 and the Douglas DC-9. Boeing was badly behind however when the 737 program was initiated in 1964, as both of these rivals were already into their flight certification programmes. To speed up the development time, Boeing reused as much technology from the existing 707 and 727 as possible, most notably the fuselage. This gave the 737 a critical advantage over the opposition - six abreast seating compared to the 1-11 and DC-9's five abreast layout, and also made the 737 cheaper and quicker to design. But the decision also dated the design, and created problems for future modernisation, which still haunts the current Next-Generation series to this day.
The short and stubby appearance of the first 737-100 earned it the nickname among Boeing engineers as "FLUF", being an acronym for "Fat Little Ugly Fella" (or whatever), although the industry affectionately called it the "Baby Boeing".
The -100 and -200 series are identifiable by their tubular engine nacelles which are integrated into the wing and project both fore and aft of it. The engines used on the Original 737 models are Pratt and Whitney JT8D turbofans. The Originals can also be identified by the smoothly curving upsweep of the tail fin - the Classics and NG models have a noticeable "kink" at the base of the fin.
The first 737 (a 100 series) took its maiden flight April 9, 1967 and entered service in February 1968 with Lufthansa, the first foreign airline to launch a new Boeing plane. The 737-200 made its maiden flight on August 8, 1967.
Lufthansa was the only customer to purchase the 737-100 from new and only 30 aircraft were ever produced. The lengthened 737-200 was widely preferred and was produced until 1988. The launch customer of the 737-200 was United Airlines.
In the early 1980s the 737 had its first major facelift. The biggest change was to the CFM International CFM56 engines in place of the JT8Ds. The CFM56 was larger than the previous P&W unit, so the engine was slung underneath the wing rather than built into it. This posed a problem as the 737's limited ground clearance (a trait of the 707-derived fuselage) meant that the bottom surface of the engine nacelle had to be flattened out. At the same time, the 737 gained a partial glass cockpit from the 757 and 767. The first 737-300 entered service in 1984.
The Next-Generation 737 encompasses the -600, -700, -800 and -900, and amounted to what was basically a complete redesign of the 30-year old airliner.
New wings, and revised engines were the biggest engineering changes, whilst internally, the 737 was given a hi-tech glass cockpit with LCD screens and digital systems heavily inspired by that used on the 777. An all new interior was designed for the Next-Generation 737, again borrowing heavily from the 777. The 737NG is almost a new aircraft, sharing very little with previous 737s, other than fuselage frames. The parts count is down by about 33%, simplifying maintenance greatly.
In 2001, the 737 was stretched one last time to create the 737-900, which is in fact longer and carries more passengers than the 707. However, with Boeing's decision to end 757 production at the end of 2004, there are now plans to create an even higher-capacity 737 to fill the vacuum left by the 757's demise. The so-called 737-900X is still at the planning stage, differering from the standard 737-900 by increasing the number of exit doors, which allows more passengers per widespread safety standards.
Today, the 737 remains the most popular jetliner in the world. Part of its success is down to its popularity among low cost carriers, such as Southwest Airlines, and Ryanair, who exclusively operate the 737.
There have been three basic generations of the 737, known as the Original, Classic and Next-Generation (NG) models.
Some versions in different generations correspond to each other in size. These are:
When referring to variants of the 737, Boeing and the airlines often collapse the model (737) and the capacity designator (-300, -800, etc.) into a smaller form, either 733 or 738. The exception is the 737-700, which is abbreviated as 73G, in order to avoid confusion with the model number itself. These notations may be found in aircraft manuals or airline timetables.
Also in production is the Boeing Business Jet (BBJ and BBJ2). The BBJ is based on the 737-700 but is fitted with the stronger wings from the 737-800, while the BBJ2 is based upon the 737-800. The BBJ has increased range (by use of extra fuel tanks) over the other 737 models and is currently operated by some airlines on premium flights between North America and Europe.
There are several versions of the 737 with special duties.