Template:Infobox AircraftThe Boeing 737 is the world's most popular medium-range, narrowbody commercial passenger jet aircraft. With 6,160 ordered and 5,009 delivered, it is the most ordered and produced commercial airliner of all time and has been continuously manufactured by Boeing since 1967. The 737 is now so widely used that at any given time, there are over 1,250 airborne worldwide. On average, one takes off or lands every five seconds.

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. However, one of the wing sets failed when submitted to static test on a bench at 95% of designed maximum load capacity. The wing had to be redesigned, but this provided the aircraft with a superb wing capable of operating both with short runways and high altitude efficiency. Even with the early shortcomings, 737 was cheaper and quicker to design, featuring six-abreast seating compared to the 1-11 and DC-9's five-abreast layout.

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 low-bypass 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. The inaugural flight for United was flown on April 28, 1968 from Chicago O'Hare (ORD) to Grand Rapids, Michigan. (GRR) United B-737-200 N9003U flew this first 737 revenue flight. After aircraft #135, an important improvement was applied to the subsequent units and mod kits made available for the precedents: the less efficient 727-style thrust reversers was replaced by exclusive target thrust reversers designed in conjunction with Rohr, but such modification cost US$24 million to Boeing.

In the early 1980s the 737 had its first major facelift. The biggest change was the usage of CFM International CFM56 engines in place of the JT8Ds. The CFM56 is a high-bypass turbofan and thus its diameter 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 gearbox and accessories normally fitted to the bottom of the engine had to be fitted to the side — giving the cowling the fattened hamster cheek appearance that is often confused with a flattening of the nacelle geometry. At the same time, the 737 gained a partial glass cockpit from the 757 and 767. The first 737-300 entered service in 1984.

By the 1990s, the 737 had lost ground technologically to the newer Airbus A320. In 1993, Boeing initiated the 737-X or Next Generation (NG) program.

The Next-Generation 737 encompasses the -600, -700, -800 and -900, and amounted to a complete redesign of the 30-year old airliner. The 737NG is an entirely new aircraft, sharing very little with previous 737s, other than fuselage frames. New wings, new avionics and revised engines were the biggest engineering changes. The 737 was given a glass cockpit with CRT screens (except the -900, which had newer and higher tech LCD screens) and digital systems inspired by the ones that were used on the 777. A new interior was designed for the Next-Generation 737, again borrowing heavily from the 777. The parts count is down by about 33%, reducing weight and simplifying maintenance. Additional changes since its introduction include a new interior and performance enhancing winglets which reduce fuel consumption and improve take-off and climb performance.

In 2001, the 737 was stretched one more time to create the 737-900, which is in fact longer and carries more passengers than the 707, and steps into the capacity of the 757-200. As a result of weak demand Boeing closed the 757 line in 2004. Early in 2005, the 737 lost its distinctive "eyebrow" windows in the cockpit - once a requirement in the 1960s due to the FAA certification requirement for a minimum windscreen area and also to offer increased visibility in banking maneuvers but all now deemed unnecessary, and a retrofit kit will be offered to remove the windows on existing aircraft.

Starting in 2004, short-field performance changes were developed in response to the needs of a Brazilian customer, Gol Transportes Aéreos, an airlines that uses the Santos Dumont Regional Airport in Rio de Janeiro with its longest runway having only 4,341 feet (1,323 meters) in length. That runway is short compared to other runways and could not accommodate larger airplanes at higher approach speeds with full payloads.

The modifications made available optionally as the Short Field Performance package on the 737-600, -700 and -800 models are standard equipment for the 737-900ER. These enhancements include a two-position tail skid that enables reduced approach speeds, sealed leading-edge slats that provide increased lift during takeoff, and increased flight spoiler deflection on the ground that improves takeoff and landing performance. Also, payload capability for landing went up 8,000 pounds on the 737-800 and 737-900ER and up 4,000 pounds on the 737-600 and 737-700, while the payload capability for takeoff went up 2,000 pounds on the 737-800 and 737-900ER and up 400 pounds on the 737-600 and 737-700.

The first 737-800 SFP was delivered to GOL in late August 2006. Meanwhile, 11 customers have queued up for deliveries of 250 SFP-packaged models as of 2006.

In July 2005, Boeing announced the 737-900ER (Extended Range), formerly known as the 737-900X. The 737-900ER is the same size as the 737-900, but, with the addition of a pair of exit doors and a flat rear pressure bulkhead, will carry 26 additional passengers, raising the maximum capacity from 189 to 215 in a single-class layout. The first 737-900ER is scheduled for delivery in the first half of 2007. Lion Air will be the launch customer, with an order of 30.

Boeing has also recently announced the 737-700ER (Extended Range). The 737-700ER is the same size as the 737-700, but with the addition of extra fuel tanks and a higher MTOW (Maximum Take-Off Weight). All Nippon Airlines (ANA) will be the launch customer.

Boeing has already hinted that a clean sheet replacement for the 737 (dubbed "Y1") will be the company's next major project after the 787, although it is still unclear if the existing 737 will receive yet one more facelift in the next 7 to 10 years. Currently the "clean sheet replacement" is also known as the 737 RS (Replacement Study).

On February 13 2006, Boeing reached a milestone by delivering the 5,000th 737 to Southwest Airlines. The 737-700 is the 447th 737 to join the carrier's fleet of all Boeing 737 jets.

The Boeing 737 has also been popular as a military variant. There are several versions of the 737 with these special duties:

• T-43, a 737-200 - Used to train aircraft navigators for the U.S. Air Force. Some were modified into CT-43s which are used to transport passengers.
• SLAMMR: Maritime reconnaissance/transport aircraft, fitted with SLAMMAR (side-looking multi-mission airborne radar.) Three aircraft were sold to the Indonesian Air Force.

• C-40A Clipper, a 737-700C - The U.S. Navy's replacement for the C-9 Skytrain II. The C-40B and C-40C are used by the U.S. Air Force for transport of Generals and other senior leaders.
• Project Wedgetail, a 737-700IGW (roughly similar to the 737-700ER) - This is an AEW&C version of the 737NG. Australia is the first customer, with Turkey, South Korea, and Italy anticipated.
• P-8 Multimission Maritime Aircraft (MMA), a 737-800ERX - On June 14, 2004, Boeing's Integrated Defense Systems division beat Lockheed Martin in the contest to replace the P-3 Orion maritime patrol aircraft. Eventual orders may exceed 100 from the U.S. Navy. The P-8 is unique in that it has 767-400ER-style raked wingtips, instead of the blended winglets available on other 737NG variants.

Many countries operate the 737 in government or military applications:

• Passenger and Cargo variants: Brazil, Chile, India, Indonesia, Kuwait, Mexico, Niger, Peru, South Korea, Taiwan (Air Force One of Taiwan), Thailand, United Arab Emirates, United States (Air Force, Navy), Venezuela.
• Wedgetail Airborne Radar: Australia

On August 21 2006 Sky News alleged that Boeing's Next Generation 737s built from 1994 to 2002 contained defective parts. The report stated that various parts of the airframe produced by Ducommun were found to be defective by Boeing employees but that Boeing refused to take action. Boeing said that the allegations were "without merit". ^[1]

There are 9 variants of the 737 and launched on nine separate occasions. The 737s also fall into three different generations. The "Original" models are the 737-100 launched in 1964 and entering service in 1968 and the 737-200 launched in 1965 and entering service in 1968. The "Classic" models were the 737-300 launched in 1980 and entering service in 1984, the 737-400 launched in 1985 and entering service in 1988, and the 737-500 launched in 1987 and entering service in 1990. The "Next Generation" variants encompass the 737-700 launched in 1993 and entering service in 1998, the 737-800 launched in 1994 and entering service in 1998, the 737-600 launched in 1995 and entering service in 1998, and lastly the 737-900 launched in 1997 and entering service in 2000. Although there are nine variants of the 737, numerous versions of most exist.

The initial model was the 737-100, and was the smallest model. Lufthansa was the launch customer (which, by extension, launched the 737 itself.) Only a total of 30 737-100s were ordered and delivered. No 737-100s are now left in service or in airworthy condition; however the original Boeing prototype (now owned by NASA) is now exhibited in the Museum of Flight in Seattle

The 737-200 was an extended version of the 737-100, in order to accommodate the U.S. market. United Airlines was the launch customer. The 737-200 was later updated as the 737-200 Advanced, which became the standard production version. The 737-200 Advanced was also available as Convertible and Quick Change variants. In addition, the 737-200 Advanced was also sold as the 737-200 Executive Jet and 737-200HGW (High Gross Weight) variants. These models are quickly heading for extinction owing to poorer fuel efficiency, high noise emissions (despite the vast majority having had their JT8Ds fitted with hush kits) and escalating maintenance costs - although a large number of -200s are still in operation with "second tier" airlines and those of developing countries. These 737s are powered by Pratt & Whitney JT8D low-bypass ratio turbofan engines.

737-200C

This model (C for "Convertible") could be converted between passenger and cargo use. Wien Air Alaska was the launch carrier for this aircraft. Alaska Airlines now operates the largest fleet of 200 Convertible 737's.

737-200QC

The QC (for "Quick Change") was a further variation of the 737-200C, allowing rapid switching between roles.

The 737-300 was the new base model, and was slightly longer than the 737-200. USAir and Southwest Airlines were the launch customers with Jat Airways being the launch customer in Europe. The -300 series avionics were either a mixture of the old "clockwork" dials and EFIS (Electronic Flight Instrumentation System), or more usually, primarily EFIS in nature. Also, the aircraft was re-engined with high-bypass CFM56 series engines. The engines were slightly quieter during takeoffs, etc than the JT8D's used on the 727 and 737-200 and were much more powerful and did not blow black smoke. This model came with an interior similar to the recently launched Boeing 757

The 737-400 was stretched beyond the 737-300, primarily to accommodate charter airlines. USAir and Pace Airlines were the launch customers. Alaska Airlines is the largest operator, with 40 aircraft, followed by Malaysia Airlines with 39 aircraft.

The 737-400F is not a model delivered by Boeing but a converted 737-400 to an all cargo aircraft. Alaska Airlines was the first in the world to convert one of their 400s from regualr service to an aircraft with the ability to handle 10 pallets. The Airline also plans to convert 4 more into a fixed combi aircraft for half passenger and freight scheduled to enter service starting in September of 2006.

The 500 was the last of the second generation of 737s to be developed. With the growth of the 737-300 and 737-400, Boeing introduced the shortened 500 for the airlines replacing the earlier 737-100 and 737-200. It incorporated greater range, better economics, and a more modern looking cabin. The CFM engines were also much less noisy than the lower bypass ratio JT8D engines. The 500 was offered on May 20 1987 and received 20 orders by Braathens SAFE (currently known as SAS Braathens), 13 from Southwest Airlines, 3 from Maersk Air, and 3 from Euralair. It received FAA certification February 12 1990 and introduction into service by Southwest Airlines on February 24 1990. Measuring only 0.5m (1ft,8 in) longer than the 737-200, it would prove to be the ideal substitute for this model in the second generation of the 737. A total of 389 were ordered and delivered. Of these 389, 270 were ordered prior to its first commercial flight, and 119 afterwards.

Along with the 737-700 and 737-800, the 737-600 was one of the three initial 737NG variants. The 737-600 superseded the 737-500. Scandinavian Airlines System was the launch customer, but since then this model has suffered from weak sales, being profitable for airlines on primarily long and thin routes.

The direct Airbus equivalent is the A318. The Boeing 717 held approximately the same number of passengers, but was optimized for regional routes and did not have the range of the 737-600. Production of the 717 has concluded as of mid-2006, leaving the 737-600 as the only 100-passenger market aircraft offered by Boeing.

The 737-600 competes directly with the Airbus A318 and the Embraer 195.

This model was launched by Southwest Airlines. It has the longest range of any 737 and is a direct competitor to the A319. It usually seats 132 passengers in a two class cabin or 149 in all economy configuration. An executive conversion is offered as the BBJ1 . The BBJ1 is fitted with stronger wings and landing gear from the 737-800, and 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.

737-700C

This is again a convertible version where the seats can be removed for the plane to carry cargo. There is a large door on the left side of the airplane. The U.S. Navy launched the 737-700C.

737-700ER

Boeing launched this version on January 31, 2006.[1] All Nippon Airways will be the launch customer, with an entry into service date in early 2007. The 737-700ER is essentially a mainline passenger version of the BBJ1 and 737-700IGW. It will offer a range of 5,510 nautical miles, with seating for 126 passengers in a 2-class configuration. A competitor to this model would be the A319LR.

The 737-800 was a longer version of the 737-700, directly replacing the 737-400. Hapagfly was the launch customer. An executive conversion is offered as the BBJ2, and the 737-800ERX ("Extended Range") is available as a military variant.

The 737-800 seats 162 passengers in a 2-class layout, or 189 in 1-class. It has a range of 5665km (3060 nautical miles) and is powered by CFMI CFM 56-7 engines.

The direct Airbus equivalent is the A320.

In order to better compete with offerings from Airbus, Boeing later introduced the 737-900, which was the longest variant. However, the 900 did not have enough exit doors to meet FAA regulations, so its passenger capacity was limited by law rather than by payload. Alaska Airlines launched the 737-900. 54 were sold as of August 2006. The 900 can still be ordered but the much improved ER version should prove more popular.

737-900ER

This is the newest addition to the Boeing 737 family and was introduced to meet the range and passenger capacity of the discontinued 757-200 (the B757-300 model will be replaced by the new 787 Dreamliner), with new exit doors and fuel tanks. The rear pressure bulkhead was flattened and there were other aerodynamic changes over the -900 variant. Its advanced wing aerofoil design provides an economic cruise speed of Mach 0.78 with sprint capability of Mach 0.82. Lion Air of Indonesia launched the 737-900ER. An executive conversion is offered as the BBJ3.

The 737-900ER typically seats 180 passengers in a 2-class configuration, but in a single-class layout seats up to 215 passengers. Powered by the same CFMI CFM56-7 engines as the -700ER model, the 900ER has a range of 5,900km (3,200 nautical miles). Final assembly of the first Boeing 737-900ER began in June 2006.

The 900ER was rolled out of the Renton, WA factory on August 8, 2006 for its launch customer, Lion Air.

The direct Airbus equivalent is the A321, though the 737-900 is slightly smaller.

Recent accidents

• January 3, 2004 - Flash Airlines, Flight 604, a 737-300 crashed shortly after take-off from Sharm el-Sheikh, Egypt killing all 148 passengers and crew. [2]
• February 3, 2005 - Kam Air, Flight 904, a 737-200 crashed into a mountain 20 miles (30 km) east of Kabul, Afghanistan killing all 96 passengers and eight crew. [3]
• August 14, 2005 - Helios Airways, Flight 522, a 737-300 crashed after cabin decompression and crew loss of consciousness, north of Athens, killing all 121 passengers and crew.
• August 23, 2005 - TANS Peru, Flight 204, a 737-200 crashed during a storm in the Peruvian jungle, killing 40 of the 92 passengers and six crew. [4]
• September 5, 2005 - Mandala Airlines, Flight 091, a 737-200 crashed in Medan, Indonesia, killing 102 of the 117 passengers and crew, plus 47 more on the ground. [5]
• October 22, 2005 - Bellview Airlines, Flight 210, a 737-200 crashed shortly after take-off from Lagos, Nigeria, killing all 111 passengers and six crew. [6]
• December 8, 2005 - Southwest Airlines, Flight 1248, a 737-700 slid off the runway during a heavy snowstorm landing on runway 31C (length 6,500 - available to land distance of 5,826) at Chicago's Midway Airport and into a nearby intersection, hitting two cars killing 1 car passenger and injuring eleven other people, including three jet passengers.[7]
• September 29, 2006 - Gol Transportes Aéreos, Flight 1907, a 737-800 Brazilian airliner with 155 people on board was reported missing over the northern state of Pará, following an apparent collision with a small plane, an Embraer Legacy 600. The flight of the Brazilian airline Gol was en route from Manaus in the state of Amazonas to the capital Brasilia when it disappeared. The small plane involved in the reported collision performed a successful emergency landing at the Cachimbo Air Force Base, in the western state of Mato Grosso. The aircraft in question (PR-GTD), a Boeing 737-800 SFP (Short Field Performance) was only delivered to GOL from Boeing on September 12, and had barely 200 flight hours at the time of the incident.
• October 3 2006 - Mandala Airlines, Mandala Airlines Flight 394, a 737-200, skidded and came to a stop in a swamp about 50 meters off the runway when landing in reduced visibility due to regional forest fire haze which had cut visibility to 400 meters (1,312 feet) at Tarakan Airport, Kalimantan Selatan (Borneo), Indonesia with 110 people on board; no one was injured.

Accidents summary Statistics as of December 12, 2005:

• Hull-loss Accidents: 114 with a total of 3182 fatalities
• Other occurrences: 6 with a total of 242 fatalities
• Hijackings: 96 with a total of 325 fatalities

Controversy

• In August 2006, Sky News reported that whistleblowers claimed that parts being used in the Boeing 737NG model built between 1994 and 2002 were of a poor fit to the aircraft and were thus wrongly made endangering the safety of those onboard. Boeing responded by claiming the allegations were 'without merit' and that the aircraft were very safe. The whistleblowers were reported to be former auditors Taylor Smith and Jeannine Prewitt who installed the parts even though they knew of their defects.

• The popularity of the 737 can be traced in large part to its use by Southwest Airlines, which has been a launch customer on the -300, -500, and -700 variants. Southwest uses no other aircraft type and accounts for over 9% of the total number of delivered 737 aircraft.
• The Boeing 737s has several nicknames:
  • The first 737s were nicknamed, "The Baby Boeing" because it looked like a baby 707 to many pilots.
  • An additional early nickname was "Fat Albert" since it was only a foot longer in length than the wing span.
  • The 737 has also been nicknamed the "flying football" due its resemblance to the shape of an American football.
  • At United Airlines the 737 is nicknamed "Guppy".
• Engines on the 737 Classic series (300,400,500) and Next-Generation series (600, 700, 800, 900) do not have circular inlets, as most aircraft do. Engineers needed additional space to locate equipment on the more powerful engines, but because the 737 sits lower to the ground than most aircraft, the enlarged engine would sit too close to the ground. Instead, the engineers placed equipment on the engine's sides, giving the engine a pronounced triangular shape. Boeing and CFM International, the engine manufacturer, claim that the triangular shape actually yields slightly improved performance. The necessary nacelle redesign is known in the industry as "hamsterisation", because of the resemblance of the shape to the popular domesticated rodent.
• The 737 uses the same basic fuselage as the 707, 727 and 757.
• Most 737 cockpits are equipped with "eyebrow windows" positioned above the main glareshield. Eyebrow windows were a feature of the original 707. They allowed for greater visibility in turns, and offered better sky views if navigating by stars. With modern avionics, they became redundant, and many pilots actually placed newspapers or other objects in them to block out sun glare. They were eliminated from the 737 cockpit design in 2004.
• Southwest Airlines is actually in the process of plugging the "eyebrow windows" on their entire fleet of 737's. New aircraft delivered from Boeing after 2004 come without "eyebrow windows."
• Blended winglets are currently a very popular retrofit on the 737. These winglets stand approximately 8 feet tall and are installed at the end of the main wings. They help aerodynmics (resulting in reduced fuel burn, less engine wear, and less noise on take offs).
• The fuselage of the 737 actually has a smaller diameter than that of the engine nacelle of the GE90-115B turbo-fan jet engine. The GE90-115B is used to power the Boeing 777-200LR and 777-300ER.
• The 737 has no main landing gear doors. The main landing gear (under the wings at mid-cabin), rotate into wells in the plane's belly, and seals activate to aerodynamically smooth (or "fair") the wheels in the wells. The sides of the tires are exposed to the air in flight. When observing a 737 take off, or at low altitude, the dark circles of the tires can be plainly seen. Boeing states that this design saves weight and reduces complexity.
• With the number of 737s in use, it is estimated that one 737 takes-off every 5 seconds somewhere in the world.
• 737s are not equipped with fuel dump systems. Depending upon the nature of the emergency, 737s either circle to burn-off fuel or land overweight.
• "737" is the first lyric in the song Travelin' Band, recorded by rock band Creedence Clearwater Revival.

• Flight International coverage on 5000th 737
• Boeing 737 Technical Information
• Aircraft-Info.net - Boeing 737-400
• Planemad.net - Boeing 737 all versions Production Lists
• The Boeing 737 Management Reference Guide (for B737 airline pilots)
• Official Boeing page
• List of 737NG operators
• Boeing 737NG Flight Tutorial for FS2004
• How to start a real Boeing 737 Tutorial
• Boeing 737 image pool on flickr
• Aviation Safety Network

Wikimedia Commons has media related to Boeing 737.

• Bombardier CSeries
• Embraer E-jets

Related development

• Boeing Business Jet
• T-43
• Wedgetail
• C-40 Clipper
• P-8 MMA

Aircraft of comparable role, configuration, and era

• Airbus A320
• Bae 146
• Boeing 717
• Bombardier CSeries
• EMBRAER E-Jets

Related lists

• List of Boeing 737 operators
• List of Boeing 737 orders
• List of airliners

Template:Boeing Airliners