171-743: The Boeing 737 MAX is the fourth generation of the Boeing 737 , a narrow-body airliner manufactured by Boeing Commercial Airplanes . It succeeds the Boeing 737 Next Generation (NG) and competes with the Airbus A320neo family . The series was announced in August 2011, first flown in January 2016, and certified by the US Federal Aviation Administration (FAA) in March 2017. The first 737 MAX delivered to
342-401: A Boeing 777 -300 reaches that point at 3,000 nautical miles (5,600 km). It is more fuel-efficient to make a non-stop flight at less than this distance and to make a stop when covering a greater total distance. Very long non-stop passenger flights suffer from the weight penalty of the extra fuel required, which means limiting the number of available seats to compensate. For such flights,
513-443: A Supplemental type certificate (STC), in lieu of a new design approval. The MAX's first flight took place on January 29, 2016, at Renton Municipal Airport , nearly 49 years after the maiden flight of the original 737-100, on April 9, 1967. The first MAX 8, 1A001, was used for aerodynamic trials: flutter testing, stability and control, and takeoff performance-data verification, before it was modified for an operator and delivered. 1A002
684-487: A jet engine with its efficiency given by its airspeed divided by the thrust-specific fuel consumption and the specific energy of the fuel. Turboprops have an optimum speed below 460 miles per hour (740 km/h). This is less than jets used by major airlines today, however propeller planes are much more efficient. The Bombardier Dash 8 Q400 turboprop is used for this reason as a regional airliner. Jet fuel cost and emissions reduction have renewed interest in
855-801: A 3.5 L/100 km (67 mpg ‑US ) fuel consumption per passenger, on average. The worst-performing flights are short trips of from 500 to 1500 kilometres because the fuel used for takeoff is relatively large compared to the amount expended in the cruise segment, and because less fuel-efficient regional jets are typically used on shorter flights. New technology can reduce engine fuel consumption, like higher pressure and bypass ratios , geared turbofans , open rotors , hybrid electric or fully electric propulsion ; and airframe efficiency with retrofits, better materials and systems and advanced aerodynamics. A powered aircraft counters its weight through aerodynamic lift and counters its aerodynamic drag with thrust . The aircraft's maximum range
1026-475: A 57 g/RPK CO₂ emissions (equivalent to 18.1 g/km of fuel, 2.27 L/100 km [104 mpg ‑US ] per passenger), 40% lower than IAG or Lufthansa (95 g CO₂/RPK - 30 g/km of fuel, 3.8 L/100 km [62 mpg ‑US ] per passenger), due to their business classes , lower-density seating , and flight connections . In 2021, the highest seating density in its A330neo , with 459 single-class seats, enabled Cebu Pacific to claim
1197-634: A VIP aircraft by the Mexican Air Force for 23 years under registration TP-03. TP-03 would be broken up in 2006. The first 737-100, NASA 515, is on static display in the Museum of Flight in Seattle and is the last surviving example of the type. The 737-200 was a 737-100 with an extended fuselage, launched by an order from United Airlines in 1965 and entered service with the launch customer in April 1968. Its unit cost
1368-461: A customer was a MAX 8 to Malindo Air , which accepted and began operating the aircraft in May 2017. The 737 MAX is based on earlier 737 designs, with more efficient CFM International LEAP engines, aerodynamic changes including distinctive split-tip winglets , and airframe modifications. The 737 MAX series has been offered in four variants, with 138 to 204 seats in typical two-class configuration, and
1539-600: A damaged door seal. Yield management allows the optimization of the load factor , benefiting the fuel efficiency , as is the air traffic management optimization. By taking advantage of wake updraft like migrating birds ( biomimicry ), Airbus believes an aircraft can save 5-10% of fuel by flying in formation , 1.5–2 nmi (2.8–3.7 km) behind the preceding one. After Airbus A380 tests showing 12% savings, test flights were scheduled for 2020 with two Airbus A350s , before transatlantic flight trials with airlines in 2021. Certification for shorter separation
1710-458: A design team, which cooperated with CFM International to select, modify and deploy a new engine and nacelle that would make the 737-300 into a viable aircraft. They chose the CFM56-3B-1 high-bypass turbofan engine to power the aircraft, which yielded significant gains in fuel economy and a reduction in noise, but also posed an engineering challenge, given the low ground clearance of the 737 and
1881-512: A fourth production line for the 737 MAX would open at the Boeing Everett Factory in Everett, Washington . The line will replace the discontinued Boeing 787 line at the factory. However, after the January 2024 Alaska Airlines Flight 1282 accident in which a door plug became detached (after not being bolted in place by Boeing) and resulted in an uncontrolled decompression of the aircraft,
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#17328728724782052-649: A fuel consumption of 58 mpg ‑US (4.06 L/100 km) per revenue passenger for domestic flights, or 32.5 g of fuel per km, generating 102 g CO₂ / RPK of emissions. In 2013, the World Bank evaluated the business class carbon footprint as 3.04 times higher than economy class in wide-body aircraft , and first class 9.28 times higher, due to premium seating taking more space, lower weight factors, and larger baggage allowances (assuming Load Factors of 80% for Economy Class, 60% for Business Class, and 40% for First Class). At constant propulsive efficiency,
2223-700: A fuel tanker in the air." Singapore Airlines Flights 21 and 22 were re-launched in 2018 with more seats in an A350-900 ULR. In the late 2000s/early 2010s, rising fuel prices coupled with the Great Recession caused the cancellation of many ultra-long haul, non-stop flights. This included the services provided by Singapore Airlines from Singapore to both Newark and Los Angeles that was ended in late 2013. But as fuel prices have since decreased and more fuel-efficient aircraft have come into service, many ultra-long-haul routes have been reinstated or newly scheduled (see Longest flights ). The efficiency can be defined as
2394-539: A fund for the families of crash victims. From mid-April 2019, Boeing announced that it was temporarily cutting production of the 737 aircraft from 52 per month to 42 amid the 737 MAX groundings. Production of the LEAP-1B engine continued at an unchanged rate, enabling CFM to catch up its backlog within a few weeks. As the 737 MAX recertification moved into 2020, Boeing suspended production from January to conserve funds and prioritize stored aircraft delivery. The 737 MAX program
2565-456: A fuselage similar to the 737 though slightly larger, and would make use of the advanced composite technology developed for the 787 Dreamliner . Boeing also considered a parallel development along with the 757 replacement, similar to the development of the 757 and 767 in the 1970s. On August 13, 2015, the first 737 MAX fuselage completed assembly at Spirit Aerosystems in Wichita, Kansas , for
2736-518: A gravel deflector on the nose gear and a vortex dissipator extending from the front of the engine. Alaska Airlines used the gravel kit for some of its combi aircraft rural operations in Alaska until retiring its -200 fleet in 2007. Air Inuit , Nolinor Aviation and Chrono Aviation still use the gravel kit in Northern Canada. Canadian North also operated a gravel-kitted 737-200 Combi, but this
2907-669: A high density of 1.36 seat/m due to a low 9% premium seating. On the other side, the least efficient was British Airways at 27 pax-km/L (3.7 L/100 km [64 mpg ‑US ] per passenger), using fuel-inefficient Boeing 747-400s with a low density of 0.75 seat/m due to a high 25% premium seating, in spite of a high 82% load factor. In 2018, CO₂ emissions totalled 918 Mt with passenger transport accounting for 81% or 744 Mt, for 8.2 trillion revenue passenger kilometres : an average fuel economy of 90.7 g/RPK CO₂ - 29 g/km of fuel (3.61 L/100 km [65.2 mpg ‑US ] per passenger) In 2019, Wizz Air stated
3078-423: A need for a new aircraft to supplement the 727 on short and thin routes. Preliminary design work began on May 11, 1964, based on research that indicated a market for a fifty to sixty passenger airliner flying routes of 50 to 1,000 miles (100 to 1,600 km). The initial concept featured podded engines on the aft fuselage, a T-tail as with the 727, and five-abreast seating. Engineer Joe Sutter relocated
3249-456: A new Boeing aircraft. Lufthansa was the only significant customer to purchase the 737-100 and only 30 aircraft were produced. The -200 was rolled out on June 29, 1967, and had its maiden flight on August 8, 1967. It was then certified by the FAA on December 21, 1967. The inaugural flight for United Airlines took place on April 28, 1968, from Chicago to Grand Rapids, Michigan . The lengthened -200
3420-491: A range of 3,300 to 3,850 nautical miles [nmi] (6,110 to 7,130 km; 3,800 to 4,430 mi). The 737 MAX 7, MAX 8, and MAX 9 are intended to replace the 737-700, -800, and -900 respectively, and a further-stretched 737 MAX 10 is available. However, as of October 2024, the MAX ;7 and MAX 10 have not been certified, with the FAA declining to provide a timetable for approval. As of October 2024,
3591-502: A range similar to the Airbus A319LR . The 737-800 was a stretched version of the 737-700 launched on September 5, 1994. The -800 seats 162 passengers in a two-class or 189 passengers in a high-density, one-class layout. Launch customer Hapag-Lloyd Flug (now TUIfly ) received the first one in April 1998. The -800 replaced directly the -400 and aging 727-200 of US airlines. It filled also the gap left by Boeing's decision to discontinue
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#17328728724783762-416: A retrofit was provided for active aircraft. Longer nacelle/wing fairings were introduced, and the airflow over the flaps and slats was improved. The production line also introduced an improvement to the flap system, allowing increased use during takeoff and landing. All these changes gave the aircraft a boost to payload and range, and improved short-field performance. Both the first and last 737-100s became
3933-694: A route like Bangkok–Tokyo: direct routing saves 190 kg (420 lb) fuel by flying 40 km (25 mi) less; 600 kg (1,300 lb) more fuel is consumed if flying 600 m (2,000 ft) below optimum altitude without vertical flight profile optimization; cruising Mach 0.01 above the optimum speed consumes 800 kg (1,800 lb) more fuel; 1,000 kg (2,200 lb) more fuel on board consumes 150 kg (330 lb) more fuel while 100 litres (22 imp gal; 26 US gal) of unused potable water consumes 15 kg (33 lb) more fuel. Operational procedures can save 35 kg (77 lb) fuel for every 10-minute reduction in use of
4104-463: A safety reform law passed in response to the MAX crashes. The act requires airliners to be fitted with an engine-indicating and crew-alerting system (EICAS) if type certificated after December 31, 2022. Adding this feature would make the MAX 7 and MAX 10 different from other MAX variants, necessitating additional training for pilots. In November 2022, Boeing announced expected delays to the certification of
4275-439: A single-class layout with slimline seats requiring an extra pair of exit doors . The MAX 200 would be 20% more cost-efficient per seat, including 5% lower operating costs than the MAX 8 and would be the most efficient narrow-body on the market when entering service. In mid-November 2018, the first MAX 200 of the 135 ordered by Ryanair rolled out, in a 197-seat configuration. It was first flown from Renton on January 13, 2019, and
4446-491: A specifically designed aircraft, such as the (discontinued) Aerion AS2 , the Mach ;1.1 range at 3,700 nmi is 70% of the maximum range of 5,300 nmi at Mach 0.95, but increases to 4,750 nmi at Mach 1.4 for 90% before falling again. Wingtip devices increase the effective wing aspect ratio , lowering lift-induced drag caused by wingtip vortices and improving the lift-to-drag ratio without increasing
4617-495: A strengthened wing spar . The -400s first flight was on February 19, 1988, and, after a seven-month/500-hour flight-testing run, entered service with Piedmont Airlines that October. The last two -400s, i.e. the last 737 Classics series, were delivered to CSA Czech Airlines on February 28, 2000. The 737-400 was replaced by the 737-800 of the Next Generation series. The 737-400SF was a 737-400 converted to freighter, though it
4788-621: A subsonic turbofan aircraft. Airbus states a fuel rate consumption of their A380 at less than 3 L/100 km per passenger (78 passenger-miles per US gallon). Newer aircraft like the Boeing 787 Dreamliner , Airbus A350 and Bombardier CSeries , are 20% more fuel efficient per passenger kilometre than previous generation aircraft. For the 787, this is achieved through more fuel-efficient engines and lighter composite material airframes, and also through more aerodynamic shapes, winglets , more advanced computer systems for optimising routes and aircraft loading. A life-cycle assessment based on
4959-508: A test aircraft that would eventually be delivered to launch customer Southwest Airlines. On December 8, 2015, the first 737 MAX—a MAX 8 named Spirit of Renton —was rolled out at the Boeing Renton Factory . Because GKN could not produce the titanium honeycomb inner walls for the thrust reversers quickly enough, Boeing switched to a composite part produced by Spirit to deliver 47 MAXs per month in 2017. Spirit supplies 69% of
5130-557: A three-way hybrid of a blended winglet , wingtip fence , and raked wingtip . A split-tip wingtip was first proposed for the McDonnell Douglas MD-12 , a 1990s twin-deck aircraft concept. A MAX 8 with 162 passengers on a 3,000-nautical-mile (5,600 km; 3,500 mi) flight is projected to have a 1.8% lower fuel burn than a blended winglet -equipped aircraft (like many 737NG aircraft) and 1% lower over 500 nmi (930 km; 580 mi) at Mach 0.79. The new winglet has
5301-423: A time when air crew labor costs were higher relative to fuel costs. Despite the high fuel consumption, because fuel was inexpensive in that era the higher speed resulted in favorable economical returns since crew costs and amortization of capital investment in the aircraft could be spread over more seat-miles flown per day. Productivity including speed went from around 150 ASK /MJ*km/h for the 1930s DC-3 to 550 for
Boeing 737 MAX - Misplaced Pages Continue
5472-433: A total height of 9 feet 6 inches (2.90 m). Other improvements include a re-contoured tail cone , revised auxiliary power unit inlet and exhaust, aft body vortex generator removal, and other small aerodynamic improvements. The engines on the 737 MAX were also repositioned, the top of the new engine slightly higher than the top surface of the wing, resulting in a change to the aerodynamic characteristics of
5643-428: A two class and 189 in a high-density, one class layout. The launch customer Alaska Airlines received the delivery on May 15, 2001. The 737-900ER (Extended Range) is the newest and largest variant of the 737NG generation. An additional pair of exit doors and a flat rear pressure bulkhead increased its seating capacity to 180 passengers in a two-class and up to 220 passengers in a one-class configuration. The -900ER
5814-459: A variable-pitch propfan that produced less noise and achieved high speeds. In Europe in 2017, the average airline fuel consumption per passenger was 3.4 L/100 km (69 mpg ‑US ), 24% less than in 2005, but as the traffic grew by 60% to 1,643 billion passenger kilometres , CO₂ emissions were up by 16% to 163 million tonnes for 99.8 g/km CO₂ per passenger. In 2018, the US airlines had
5985-416: Is 18.4% to 20.8% of their maximum take-off weight, while single-aisle airliners are between 24.9% and 27.7%. An aircraft weight can be reduced with light-weight materials such as titanium , carbon fiber and other composite plastics if the expense can be recouped over the aircraft's lifetime. Fuel efficiency gains reduce the fuel carried, reducing the take-off weight for a positive feedback . For example,
6156-404: Is 22.9g/ ASK , or 2.86 L/100 km (82 mpg ‑US ) per seat, 3.51 L/100 km (67.0 mpg ‑US ) per passenger at its 81.5% load factor. Fuel economy in air transport comes from the fuel efficiency of the aircraft + engine model, combined with airline efficiency: seating configuration , passenger load factor and air cargo . Over the transatlantic route,
6327-470: Is 7,000 lb (3,200 kg) heavier. Boeing 737 The Boeing 737 is an American narrow-body airliner produced by Boeing at its Renton factory in Washington . Developed to supplement the Boeing 727 on short and thin routes, the twinjet retained the 707 fuselage width and six abreast seating but with two underwing Pratt & Whitney JT8D low-bypass turbofan engines. Envisioned in 1964,
6498-454: Is attained by minimizing parasitic drag , and lift-generated induced drag , the two components of aerodynamic drag. As parasitic drag increases and induced drag decreases with speed, there is an optimum speed where the sum of both is minimal; this is the best glide ratio . For powered aircraft, the optimum glide ratio has to be balanced with thrust efficiency. Parasitic drag is constituted by form drag and skin-friction drag , and grows with
6669-497: Is designed by Electroimpact. Electroimpact has also installed fully automated riveting machines and tooling to fasten stringers to the wing skin. The rate increase strained the production and by August 2018, over 40 unfinished jets were parked in Renton, awaiting parts or engine installation, as CFM engines and Spirit fuselages were delivered late. After parked airplanes peaked at 53 at the beginning of September, Boeing reduced this by nine
6840-421: Is determined by the level of efficiency with which thrust can be applied to overcome the aerodynamic drag . A subfield of fluid dynamics , aerodynamics studies the physics of a body moving through the air. As lift and drag are functions of air speed, their relationships are major determinants of an aircraft's design efficiency. Aircraft efficiency is augmented by maximizing lift-to-drag ratio , which
7011-522: Is enabled by ADS-B in oceanic airspace, and the only modification required would be flight control systems software. Comfort would not be affected and trials are limited to two aircraft to reduce complexity but the concept could be expanded to include more. Commercial operations could begin in 2025 with airline schedule adjustments, and other manufacturers' aircraft could be included. While routes are up to 10% longer than necessary, modernized air traffic control systems using ADS-B technology like
Boeing 737 MAX - Misplaced Pages Continue
7182-919: Is the name given to the 737-300/400/500 series after the introduction of the -600/700/800/900 series of the Boeing 737 family. Produced from 1984 to 2000, a total of 1,988 Classic series were delivered. Close to the next major upgrade of single aisle aircraft at Airbus and Boeing, the price of jet fuel reached a peak in 2008, when airlines devoted 40% of the retail price of an air ticket to pay for fuel, versus 15% in 2000. Consequently, in that year carriers retired Boeing 737 Classic aircraft to reduce fuel consumption; replacements consisted of more efficient 737 Next Generation or A320 family aircraft. On June 4, 2008, United Airlines announced it would retire all 94 of its Classic 737 aircraft (64 737-300 and 30 737-500 aircraft), replacing them with A320 family jets taken from its Ted subsidiary, which has been shut down. This intensified
7353-516: The 737 MAX -7/8/9/10 variants, powered by improved CFM LEAP -1B high-bypass turbofans and accommodating 138 to 204 people, entered service in 2017. Boeing Business Jet versions have been produced since the 737NG, as well as military models. As of October 2024 , 16,705 Boeing 737s have been ordered and 11,898 delivered. Initially, its main competitor was the McDonnell Douglas DC-9 , followed by its MD-80 / MD-90 derivatives. In 2013,
7524-410: The 737NG . Southwest Airlines was signed up as the launch customer in 2011. In November 2014, McNerney said the 737 would be replaced by a new airplane by 2030—probably using composite materials—that would be slightly bigger and have new engines but would retain the 737's general configuration. Boeing talked about developing a clean sheet aircraft to replace the 737. The conceived aircraft was to have
7695-475: The Air Transport Association maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate high-lift devices raised concerns about maintenance costs and dispatch reliability. The original 737 continued to be developed into thirteen passenger, cargo, corporate and military variants. These were later divided into what has become known as the four generations of
7866-689: The Airbus A318 . The 737-700, the first variant of the Next-Generation, was launched in November 1993 with an order of 63 aircraft. The -700 seats 126 passengers in a two-class or 149 passengers in a one-class layout. The launch customer Southwest Airlines took the first delivery in December 1997. The 737-700 replaced the 737-300 and competes with the Airbus A319 . The 737-700C is a convertible version where
8037-485: The Airbus A350 design includes a majority of light-weight composite materials. The Boeing 787 Dreamliner was the first airliner with a mostly composite airframe . For long-haul flights , the airplane needs to carry additional fuel, leading to higher fuel consumption. Above a certain distance it becomes more fuel-efficient to make a halfway stop to refuel, despite the energy losses in descent and climb . For example,
8208-506: The Auxiliary power unit (APU), 15 kg (33 lb) with a reduced flap approach and 30 kg (66 lb) with reduced thrust reversal on landing. Maintenance can also save fuel: 100 kg (220 lb) more fuel is consumed without an engine wash schedule; 50 kg (110 lb) with a 5 mm (0.20 in) slat rigging gap, 40 kg (88 lb) with a 10 mm (0.39 in) spoiler rigging gap, and 15 kg (33 lb) with
8379-464: The BAC One-Eleven (BAC-111), Douglas DC-9 , and Fokker F28 were already into flight certification. To expedite development, Boeing used 60% of the structure and systems of the existing 727, particularly the fuselage, which differs in length only. This 148-inch (3.76 m) wide fuselage cross-section permitted six-abreast seating compared to the rivals' five-abreast. The 727's fuselage was derived from
8550-480: The CFM LEAP -1B engine, with American Airlines intending to order 100 of these aircraft. On August 30, 2011, Boeing confirmed the launch of the 737 new engine variant, to be called the Boeing 737 MAX . It was based on earlier 737 designs with more efficient LEAP-1B power plants, aerodynamic improvements (most notably split-tip winglets ), and airframe modifications. It competes with the Airbus A320neo family that
8721-504: The CFM56 . The 737 went on to become the highest-selling commercial aircraft in terms of orders until surpassed by the competing Airbus A320 family in October 2019, but maintains the record in total deliveries. The fuselage is manufactured in Wichita, Kansas , by Boeing spin-off company Spirit AeroSystems , before being moved by rail to Renton. The Renton factory has three assembly lines for
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#17328728724788892-592: The DOJ's fraud conspiracy case against the company. Further investigations revealed the FAA and Boeing had colluded on recertification test flights and attempted to cover up important information, and that the FAA had retaliated against whistleblowers. The FAA cleared the aircraft to return to service on November 18, 2020, subject to mandated design and training changes. Canadian and European authorities followed in late January 2021. By December 2021, when Chinese authorities lifted their grounding, 180 of 195 countries had cleared
9063-606: The L-1049 in the 1950s, and from 200 for the DH-106 Comet 3 to 900 for the 1990s B737-800 . Today's turboprop airliners have better fuel-efficiency than current jet airliners, in part because of their propellers . In 2012, turboprop airliner usage was correlated with US regional carriers ' fuel efficiency . Jet airliners became 70% more fuel efficient between 1967 and 2007, 40% due to improvements in engine efficiency and 30% from airframes. Efficiency gains were larger early in
9234-608: The U.S. Air Force . Some were modified into CT-43s, which are used to transport passengers, and one was modified as the NT-43A Radar Test Bed. The first was delivered on July 31, 1973, and the last on July 19, 1974. The Indonesian Air Force ordered three modified 737-200s, designated Boeing 737-2X9 Surveiller . They were used as Maritime reconnaissance (MPA)/transport aircraft, fitted with SLAMMAR (Side-looking Multi-mission Airborne Radar). The aircraft were delivered between May 1982 and October 1983. After 40 years, in March 2008,
9405-485: The air freight share for 48%, seating density for 24%, aircraft fuel burn for 16% and passenger load factor for 12%. That same year, Cathay Pacific and Cathay Dragon consumed 4,571,000 tonnes of fuel to transport 123,478 million revenue passenger kilometers , or 37 g/RPK, 25% better than in 1998: 4.63 L/100 km (50.8 mpg ‑US ). Again in 2016, the Aeroflot Group fuel consumption
9576-406: The bleed air system improved efficiency. The new engine nacelle included chevrons , similar to those of the Boeing 787, which also helped to reduce engine noise. The 737 MAX uses a split-tip winglet , designed to reduce vortex drag , which improves fuel efficiency by maximizing lift, while staying in the same ICAO aerodrome reference code letter C gates as current Boeing 737s. It resembles
9747-466: The jet age than later, with a 55-67% gain from 1960 to 1980 and a 20-26% gain from 1980 to 2000. Average fuel burn of new aircraft fell 45% from 1968 to 2014, a compounded annual reduction 1.3% with variable reduction rate. Concorde , a supersonic transport , managed about 17 passenger-miles to the Imperial gallon, which is 16.7 L/100 km per passenger; similar to a business jet, but much worse than
9918-479: The propfan concept for jetliners with an emphasis on engine/airframe efficiency that might come into service beyond the Boeing 787 and Airbus A350 XWB. For instance, Airbus has patented aircraft designs with twin rear-mounted counter-rotating propfans. Propfans bridge the gap between turboprops, losing efficiency beyond Mach 0.5-0.6, and high-bypass turbofans, more efficient beyond Mach 0.8. NASA has conducted an Advanced Turboprop Project (ATP), where they researched
10089-407: The wing aspect ratio or by using wingtip devices at the cost of increased structure weight. By increasing efficiency, a lower cruise-speed augments the range and reduces the environmental impact of aviation ; however, a higher cruise-speed allows more revenue passenger miles flown per day. For supersonic flight, drag increases at Mach 1.0 but decreases again after the transition. With
10260-410: The -500. The Boeing 737 Next Generation , abbreviated as 737 Next Gen or 737NG , is the name given to the main models 737-600/700/800/900 series and the extended range -700ER/900ER variants of the Boeing 737 family. It has been produced since 1996 and introduced in 1997, with a total order of 7,097 aircraft, of which 7,031 have been delivered as of May 2019 . The primary goal was to re-engine
10431-463: The 707. The proposed wing airfoil sections were based on those of the 707 and 727, but somewhat thicker; altering these sections near the nacelles achieved a substantial drag reduction at high Mach numbers. The engine chosen was the Pratt & Whitney JT8D -1 low-bypass ratio turbofan engine, delivering 14,500 pounds-force (64 kN ) of thrust. The concept design was presented in October 1964 at
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#173287287247810602-450: The 737 airframe , including the fuselage, thrust reverser, engine pylons , nacelles , and wing leading edges . A new spar-assembly line with robotic drilling machines was expected to increase throughput by 33%. The Electroimpact automated panel assembly line sped up the wing lower-skin assembly by 35%. Boeing planned to increase its 737 MAX monthly production rate from 42 planes in 2017, to 57 planes by 2019. The new spar-assembly line
10773-470: The 737 MAX aircraft to about 47 a month by the end of 2023 as the company looked to extend its recovery from successive crises. On July 12, the company said it had met its goal of increasing 737 production to 31 per month when it reported its June order and delivery tally. In September, however, the company noted that it was regularly having to pause production due to component shortages and other supply chain problems. In late January 2023, Boeing announced that
10944-571: The 737 MAX has 4,793 unfilled orders and 1,654 deliveries. The 737 MAX has been involved in two fatal accidents: Lion Air Flight 610 in late 2018 and Ethiopian Airlines Flight 302 in early 2019. 346 people died in total. Contributing to the accidents was the Maneuvering Characteristics Augmentation System (MCAS), which activated unexpectedly due to erroneous angle of attack data, and remained active because of pilot error caused by inadequate training. The aircraft
11115-404: The 737 MAX to return to service. In January 2024, the doorway closure blew out of an unused exit doorway on Alaska Airlines Flight 1282 , causing an uncontrolled decompression of the aircraft. The FAA immediately mandated a grounding and inspections of all 737 MAX 9 with a similar configuration; affected aircraft were returned to service starting at the end of that month. The investigation found
11286-596: The 737 MAX; a fourth is planned to open at the Everett factory in 2024. The Boeing 737 Original is the name given to the -100/200 and -200 Advanced series of the Boeing 737 family. The initial model was the 737-100, the smallest variant of the 737 aircraft family, which was launched in February 1965 and entered service with Lufthansa in February 1968. In 1968, its unit cost was US$ 3.7M (1968), $ 32.4M today. A total of 30 737-100s were ordered: 22 by Lufthansa, 5 by Malaysia–Singapore Airlines (MSA) and 2 by Avianca with
11457-421: The 737 project would not be canceled. Consultation with Lufthansa over the previous winter had resulted in the seating capacity being increased to 100. On April 5, 1965, Boeing announced an order by United Airlines for 40 737s. United wanted a slightly larger capacity than the 737-100, so the fuselage was stretched 36 inches (91 cm) ahead of, and 40 inches (102 cm) behind the wing. The longer version
11628-524: The 737 with the high pressure ratio CFM56-7. By the early 1990s, as the MD-80 slowly withdrew from the competition following the introduction of the MD-90, it had become clear that the new A320 family was a serious threat to Boeing's market share. Airbus won previously loyal 737 customers, such as Lufthansa and United Airlines. In November 1993, to stay in the single aisle competition, Boeing's board of directors authorized
11799-586: The 737, thanks to its engines: the LEAP from CFM International and the PW1000G from Pratt & Whitney . In February 2011, Boeing CEO Jim McNerney said, "We're going to do a new airplane." The company had been developing a new aircraft to replace the 737 as part of its Yellowstone Project . In March 2011, Boeing CFO James A. Bell told investors that the company might re-engine the 737, but later that month Boeing Commercial Airplanes President James Albaugh said that
11970-432: The 737-100 for commercial flight on December 15, 1967. It was the first aircraft to have, as part of its initial certification, approval for Category II approaches , which refers to a precision instrument approach and landing with a decision height between 98 and 197 feet (30 and 60 m). Lufthansa received its first aircraft on December 28, 1967, and on February 10, 1968, became the first non-American airline to launch
12141-525: The 737-900 and competes with the Airbus A321neo . The 737 MAX 10 was proposed as a stretched MAX 9 in mid-2016, enabling seating for 230 in a single class or 189 in two-class layout, compared to 193 in two-class seating for the A321neo. The modest 66-inch (1.7 m) stretch of fuselage enables the MAX 10 to retain the existing wing and CFM Leap 1B engine from the MAX 9 with a trailing-link main landing gear as
12312-408: The Boeing 737 family: The launch decision for the $ 150 million (~$ 1.11 billion in 2023) development was made by the board on February 1, 1965. The sales pitch was big-jet comfort on short-haul routes. Lufthansa became the launch customer on February 19, 1965, with an order for 21 aircraft, worth $ 67 million (~$ 494 million in 2023) after the airline had been assured by Boeing that
12483-545: The Boeing 787 shows a 20% emission savings compared to conventional aluminium airliners, 14-15% fleet-wide when encompassing a fleet penetration below 100%, while the air travel demand would increase due to lower operating costs. Lufthansa , when it ordered both, stated the Airbus A350 -900 and the Boeing 777X -9 will consume an average of 2.9 L/100 km (81 mpg ‑US ) per passenger. The Airbus A321 featuring Sharklet wingtip devices consumes 2.2 L/100 km (110 mpg ‑US ) per person with
12654-528: The CFM56 included the U.S. Air Force with its program to re-engine KC-135 tankers. The passenger capacity of the aircraft was increased to 149 by extending the fuselage around the wing by 9 feet 5 inches (2.87 m). The wing incorporated several changes for improved aerodynamics. The wingtip was extended 9 inches (23 cm), and the wingspan by 1 foot 9 inches (53 cm). The leading-edge slats and trailing-edge flaps were adjusted. The tailfin
12825-568: The FAA NextGen or European SESAR could allow more direct routing, but there is resistance from air traffic controllers . Modern jet aircraft have twice the fuel efficiency of the earliest jet airliners . Late 1950s piston airliners like the Lockheed L-1049 Super Constellation and DC-7 were 1% to 28% more energy-intensive than 1990s jet airliners which cruise 40 to 80% faster. The early jet airliners were designed at
12996-411: The FAA announced it would not grant any production expansion of the 737 MAX until it is satisfied that more stringent quality control measures have been enacted. Following the recertification of the MAX 8 and MAX 9, Boeing resumed work to certify the MAX 7 and MAX 10. In March 2022, there were rumors that Boeing would request an exemption from the U.S. Aircraft Safety and Certification Reform Act of 2020,
13167-502: The FAA announced that the MAX had been cleared to return to service. Before individual aircraft could resume service, repairs were required as set out in an airworthiness directive from the FAA. Airline training programs also required approval. On December 3, American Airlines made a demonstration flight for journalists to explain the FAA-required modifications, to regain public trust. The first airline to resume regular passenger service
13338-405: The FAA cleared the MAX to return to service. Before the aircraft can fly again, repairs must be implemented and airlines' training programs must be approved. Passenger flights in the U.S. are expected to resume before the end of the year. Worldwide, the first airline to resume passenger service was Brazilian low-cost Gol , on December 9, 2020. The 737 MAX 7, a shortened variant of the MAX 8,
13509-430: The FAA's certification process for the aircraft. In the twenty months the aircraft was grounded, Boeing redesigned the computer architecture that supported MCAS. As initially designed, data from just one of the aircraft's two angle-of-attack (AoA) sensors was fed into MCAS. When erroneous data from that sensor was fed into flight computers, it caused repeated uncommanded activation of MCAS, which applied nose-down trim to
13680-450: The MAX 7 and MAX 10, then expected in early 2023 and early 2024 respectively. In December, two proposals to exempt the MAX 7 and MAX 10 from the new EICAS requirements were considered for inclusion in a U.S. defense spending bill—one a simple two-year extension to the deadline, the second an exemption for aircraft whose certification applications were submitted before the law was enacted, combined with some equipment changes—but neither proposal
13851-477: The MAX crashes. Boeing would have to retrofit these design changes to all 737 MAXs already delivered in Canada, Europe, and the U.S. within three years of MAX 10 certification. Boeing requested an additional exemption for the MAX 7 in December 2023. The exemption was related to a problem with the engine anti-ice system Boeing had announced in August 2023 that affected all MAX variants. Boeing had found that if pilots left
14022-603: The MAX. In early January 2020, an issue was discovered in the MAX software update, which impacted its recertification effort. As of mid-January, Boeing expected the MAX to return to service by mid-2020. In late April, following the COVID-19 pandemic, Boeing then hoped to win regulatory approval by August 2020. Between June 29 and July 1, the FAA and Boeing conducted a series of recertification test flights. Transport Canada and EASA each concluded their own independent recertification flights in late August and early September. On November 18,
14193-598: The MCAS flight-control system and said the issues were compounded by maintenance issues and lapses by Lion Air's maintenance crews and its pilots, as well as Xtra Aerospace, a US-based company that supplied Lion Air with a replacement AoA sensor that was likely miscalibrated. In the crash of Ethiopian Airlines Flight 302, the U.S. National Transportation Safety Board and France's Bureau of Enquiry and Analysis for Civil Aviation Safety identified pilot error and inadequate training by Ethiopian Airlines as critical contributing factors to
14364-525: The MD-80 and MD-90 aircraft, following Boeing's merger with McDonnell Douglas . The 737-800 is the most widely used narrowbody aircraft and competes primarily with the Airbus A320. The 737-900 was launched in 1997 and took its first flight on August 3, 2000. It retains the MTOW , fuel capacity, trading range for payload and also the exit configuration of the -800, limiting its seat capacity to approximately 177 in
14535-407: The Next Generation program to mainly upgrade the 737 Classic series. In late 1993, after engineering trade studies and discussions with major customers, Boeing proceeded to launch a second derivative of the Boeing 737, the 737 Next Generation (NG) -600/700/800/900 series. It featured a redesigned wing with a wider wingspan and larger area, greater fuel capacity, longer range and higher MTOWs . It
14706-403: The Next Generation series. The 737-500 was offered as a modern and direct replacement of the 737-200. It was launched in 1987 by Southwest Airlines , with an order for 20 aircraft, and it flew for the first time on June 30, 1989. A single prototype flew 375 hours for the certification process, and on February 28, 1990, Southwest Airlines received the first delivery. The -500 incorporated
14877-533: The Second Generation 737 Classic -300/400/500 variants were upgraded with more fuel-efficient CFM56-3 high-bypass turbofans and offered 110 to 168 seats. Introduced in 1997, the Third Generation 737 Next Generation (NG) -600/700/800/900 variants have updated CFM56-7 high-bypass turbofans, a larger wing and an upgraded glass cockpit , and seat 108 to 215 passengers. The latest, and Fourth Generation,
15048-543: The U.S. Congress held after the Alaska Airlines Flight 1282 accident. As of February 2024, Boeing estimated that the development, testing and validation of the fix to the anti-ice system would take an additional nine to 18 months. As of February 2024, the MAX 7 and MAX 10 have not been certified, with the FAA declining to put any timetable on approval. The delays have set back the fleet plans of major carriers including Southwest Airlines and United Airlines,
15219-473: The aft fuselage instead of as a T-tail. Many designs for the engine attachment strut were tested in the wind tunnel and the optimal shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side. At the time, Boeing was far behind its competitors; the SE 210 Caravelle had been in service since 1955, and
15390-441: The aircraft and to pilot training. The FAA lifted its grounding order in 2020; all aircraft must be repaired to comply with various airworthiness directives . After being charged with fraud in connection of both crashes of the 737 MAX, Boeing settled by paying over US$ 2.5 billion in penalties and compensation: a criminal monetary penalty of $ 243.6 million, $ 1.77 billion in damages to airline customers, and $ 500 million to
15561-539: The aircraft to modern specifications, while also retaining commonality with previous 737 variants. In 1980, preliminary aircraft specifications of the variant, dubbed 737-300, were released at the Farnborough Airshow . This first major upgrade series was later renamed 737 Classic. It competed primarily with the MD-80, its later derivative the MD-90 , and the newcomer Airbus A320 family . Boeing engineer Mark Gregoire led
15732-453: The airframe and fuel is non-payload that must be lifted to altitude and kept aloft, contributing to fuel consumption. A reduction in airframe weight enables the use of smaller, lighter engines. The weight savings in both allow for a lighter fuel load for a given range and payload. A rule-of-thumb is that a reduction in fuel consumption of about 0.75% results from each 1% reduction in weight. The payload fraction of modern twin-aisle aircraft
15903-471: The airframe. Due to the aircraft's close proximity to the ground, the larger and more fuel-efficient engines did not have enough clearance. As a result, the engines were mounted higher on the wings and further forward, changing the aerodynamic characteristics of the aircraft compared to the 737NG. The MCAS software-based flight control law was implemented to account for the undesirable aerodynamic changes. The 8-inch (20 cm) taller nose-gear strut maintains
16074-414: The airworthiness of each aircraft. MAX supplier Spirit AeroSystems said it does not expect to return production rate to 52 per month until late 2022. On May 27, Boeing resumed 737 MAX production at a low production rate, with the rate planned to increase towards 31 per month in 2021. On August 19, Boeing announced that it had received new orders for the 737 MAX for the first time in 2020. Per a statement from
16245-415: The amount of energy imparted to the plane per unit of energy in the fuel. The rate at which energy is imparted equals thrust multiplied by airspeed. To get thrust, an aircraft engine is either a shaft engine – piston engine or turboprop , with its efficiency inversely proportional to its brake-specific fuel consumption – coupled with a propeller having its own propulsive efficiency ; or
16416-460: The average at 123 g and Lufthansa at 132 g – by using high-density 189-seat Boeing 737-800s . In 2015 Ryanair emitted 8.64 Bn t of CO 2 for 545,034 sectors flown: 15.85 t per 776 miles (674 nmi; 1,249 km) average sector (or 5.04 t of fuel: 4.04 kg/km) representing 95 kg per 90.6 million passengers (30.4 kg of fuel: 3.04 L/100 km or 76 g CO 2 /km). In 2016, over
16587-422: The biggest customers for the MAX 7 and MAX 10 respectively. United also gave a rare, public rebuke of Boeing saying it was "disappointed" with the company and would no longer include the MAX 10 in its fleet planning, and had a meeting with Airbus to discuss securing more favorable production slots to enable the airline to introduce A321neos more rapidly to cover the delayed MAX 10s. In mid-2011, one design objective
16758-521: The certification process, the FAA delegated many evaluations to Boeing, allowing the manufacturer to review their own product. It was widely reported that Boeing pushed to expedite approval of the 737 MAX to compete with the Airbus A320neo, which hit the market nine months ahead of Boeing's model. The first delivery was a MAX 8 on May 16, 2017 to the then Malindo Air (now Batik Air Malaysia ); it entered service on May 22. Norwegian Air International
16929-547: The company was not sure about that. The Airbus A320neo gathered 667 commitments at the June 2011 Paris Air Show , bringing its order backlog to 1,029 aircraft, an order record for a new commercial airliner. On July 20, 2011, American Airlines , which had long bought only Boeing jets, announced an order for 460 narrowbody jets including 130 A320ceo (current engine option), 130 A320neo, and 100 737NG. Officials also said they would order 100 re-engined 737s with CFM LEAP if Boeing pursued
17100-430: The company, Poland's Enter Air SA entered into an agreement to buy up to four 737s. On October 28, Boeing indicated that it expected to deliver about half of the 450 stockpiled aircraft in 2021, and the majority of the remainder in 2022, noting that some of these aircraft will need to be re-marketed and potentially reconfigured. The delivery rate will also condition the production rate for new aircraft, to avoid compounding
17271-462: The competition between the two giant aircraft manufacturers, which has since become a duopoly competition . An optional upgrade with winglets became available for the Classic and NG series. Development began in 1979 for the 737's first major revision, which was originally introduced as the 'new generation' of the 737. Boeing wanted to increase capacity and range, incorporating improvements to upgrade
17442-532: The condition that they meet the requirements set by the FAA and EASA. China's civil aviation regulator (CAAC) cleared the 94 jets stored by 11 carriers in China to fly again in December 2021. Deliveries of Chinese airplanes stored by Boeing is expected to resume in 4Q 2023. However, EASA forbade airlines from performing RNP AR approaches with the MAX. In response to the recertification, some booking sites introduced tools allowing travelers to filter results to avoid flying on
17613-511: The crash. Boeing faced legal and financial consequences , as no deliveries of the MAX could be made while the aircraft was grounded, and airlines canceled more orders than Boeing produced during this period. Boeing found foreign object debris in the fuel tanks of 35 of 50 grounded 737 MAX aircraft that were inspected and had to check the remainder of the 400 undelivered planes. The FAA curtailed Boeing's delegated authority and invited global aviation stakeholders to comment on pending changes to
17784-405: The critical fiscal factor is the quantity of fuel burnt per seat-nautical mile. For these reasons, the world's longest commercial flights were cancelled c. 2013 . An example is Singapore Airlines' former New York to Singapore flight, which could carry only 100 passengers (all business class) on the 10,300-mile (16,600 km) flight. According to an industry analyst, "It [was] pretty much
17955-450: The denser, 200-seat MAX 200), and MAX 9 replace the 737-700, -800, and -900 respectively. The further stretched 737 MAX 10 has also been added to the series. The aim was to re-engine the 737NG family using CFM LEAP-1B engines having very high bypass ratio, to compete with the Airbus A320neo family. On July 20, 2011, Boeing announced plans for a third major upgrade and respectively fourth generation of 737 series to be powered by
18126-503: The development cost for the airframe only would be 10–15% of the cost of a new program, which was estimated at US$ 10–12 billion at the time. Bernstein Research predicted in January 2012, that this cost would be twice that of the A320neo. The MAX development cost could have been well over the internal target of US$ 2 billion , and closer to US$ 4 billion . Fuel consumption is reduced by 14% from
18297-519: The engine anti-ice system running after icing was no longer an issue, the system could heat the carbon composite inlet at the front end of the pod surrounding the engine (known as a nacelle) to break and fall off, potentially damaging the engine or fuselage. Boeing said that it was working on a fix for all MAX variants and requested that it be exempted from correcting the MAX 7 before it was allowed to enter service. Boeing withdrew its exemption request in January 2024 after being asked to do so in meetings with
18468-437: The engines to the wings which lightened the structure and simplified the accommodation of six-abreast seating in the fuselage. The engine nacelles were mounted directly to the underside of the wings, without pylons, allowing the landing gear to be shortened, thus lowering the fuselage to improve baggage and passenger access. Relocating the engines from the aft fuselage also allowed the horizontal stabilizer to be attached to
18639-545: The existence of MCAS and were not required to undergo simulator training on the difference between the 737 MAX and earlier 737 versions. Boeing and the FAA would later require simulator training to demonstrate an MCAS activation to pilots. The final report by the National Transportation Safety Committee of Indonesia into the Lion Air crash criticized Boeing's design and the FAA's certification process for
18810-508: The facility to Air China on December 15, 2018. The largest part of the suppliers cost are the aerostructures at US$ 10–12 million (35-34% of the US$ 28.5−35 million total), followed by the engines at US$ 7−9 million (25-26%), systems and interiors at US$ 5–6 million each (18-17%), then avionics at US$ 1.5–2 million (5-6%). The 737 MAX gained its airworthiness approval based on the 737 legacy series (first approved on December 15, 1967), as
18981-606: The final 737-200 aircraft in the U.S. flying scheduled passenger service were phased out, with the last flights of Aloha Airlines . As of 2018, the variant still saw regular service through North American charter operators such as Sierra Pacific Airlines . The short-field capabilities of the 737-200 led Boeing to offer the "Unpaved Strip Kit" (see the Air North example, right). This option reduced foreign object damage when operated on remote, unimproved or unpaved runways, that competing jetliners could not use safely. The kit included
19152-411: The final commercial aircraft delivered to MSA on October 31, 1969. This variant was largely overshadowed by its bigger 737-200 sibling, which entered service two months later. The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They proved to be relatively ineffective and tended to lift the aircraft up off the runway when deployed. This reduced the downforce on
19323-481: The first variant of the 737 MAX, has a longer fuselage than the MAX 7. On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8. Its first commercial flight was operated by Malindo Air on May 22, 2017. The MAX 8 replaced the 737-800 and competed with the A320neo. The 737 MAX 200 , a high-density version of the 737 MAX 8, was launched in September 2014 and named for seating for up to 200 passengers in
19494-570: The following month, as deliveries rose to 61 from 29 in July and 48 in August. On September 23, 2015, Boeing announced a collaboration with Comac to build a completion and delivery facility for the 737, in Zhoushan , China, the first outside the United States. This facility initially handles interior finishing only, but will subsequently be expanded to include paintwork. The first aircraft was delivered from
19665-554: The global 737 fleet had completed more than 184 million flights over 264 million block hours since its entry into service. It was the highest-selling commercial aircraft until being surpassed by the competing Airbus A320 family in October 2019, but maintains the record in total deliveries. The 737 MAX, designed to compete with the A320neo , was grounded worldwide between March 2019 and November 2020 following two fatal crashes. Boeing had been studying short-haul jet aircraft designs, and saw
19836-557: The horizontal stabilizer. The accident investigations revealed that the AoA sensor on Lion Air Flight 610 was miscalibrated, and the Ethiopian Airlines Flight 302 sensor was likely damaged by a bird strike during takeoff. Boeing was criticized for using data from just one of the two sensors, representing a single point of failure on a flight control system. Before the crash of Lion Air Flight 610, pilots were not informed by Boeing of
20007-482: The improvements of the 737 Classic series, allowing longer routes with fewer passengers to be more economical than with the 737-300. The fuselage length of the 737-500 is 1 foot 7 inches (48 cm) longer than the 737-200, accommodating up to 140 passengers. Both glass and older-style mechanical cockpits arrangements were available. Using the CFM56-3 engine also gave a 25 percent increase in fuel efficiency over
20178-456: The initial 737-100 made its first flight in April 1967 and entered service in February 1968 with Lufthansa . The lengthened 737-200 entered service in April 1968, and evolved through four generations, offering several variants for 85 to 215 passengers. The First Generation 737-100/200 variants were powered by Pratt & Whitney JT8D low-bypass turbofan engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984,
20349-438: The larger diameter of the engine over the original Pratt & Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of the fan (which made the engine slightly less efficient than it had been forecast to be), placing the engine ahead of the wing, and by moving engine accessories to the sides of the engine pod, giving the engine a distinctive non-circular "hamster pouch " air intake. Earlier customers for
20520-428: The last 737-100s in service. The first aircraft used by Boeing as prototype under registration N73700 was later ordered by and delivered to NASA on July 26, 1973, which then operated it under registration N515NA and retired after 30 years on September 27, 2003. The last 737-100 built and also the last operating was originally sold to Malaysia–Singapore Airlines : it was transferred to Air Florida before being used as
20691-402: The longer length. Entry into service with launch operator Southwest Airlines was expected in January 2019, but the airline deferred these orders until 2023–2024. The 737 MAX 7 replaced the 737-700 and was predicted to carry 12 more passengers and fly 400 nautical miles (740 km; 460 mi) farther than the competing Airbus A319neo with 7% lower operating costs per seat. The 737 MAX 8,
20862-516: The lowest carbon footprint with 1.4 kg (3 lb) of fuel per seat per 100 km, equivalent to 1.75 L/100 km [134 mpg ‑US ] per seat. Continuous Descent Approaches can reduce emissions. Beyond single-engine taxi , electric taxiing could allow taxiing on APU power alone, with the main engines shut down, to lower the fuel burn. Airbus presented the following measures to save fuel, in its example of an Airbus A330 flying 2,500 nautical miles (4,600 km) on
21033-477: The main wheels thereby reducing the effectiveness of the wheel brakes. In 1968, an improvement to the thrust reversal system was introduced. A 48-inch tailpipe extension was added and new target-style thrust reversers were incorporated. The thrust reverser doors were set 35 degrees away from the vertical to allow the exhaust to be deflected inboard and over the wings and outboard and under the wings. The improvement became standard on all aircraft after March 1969, and
21204-480: The maximum range speed is when the ratio between velocity and drag is minimal, while maximum endurance is attained at the best lift-to-drag ratio. Air density decreases with altitude, thus lowering drag, assuming the aircraft maintains a constant equivalent airspeed . However, air pressure and temperature both decrease with altitude, causing the maximum power or thrust of aircraft engines to reduce. To minimize fuel consumption, an aircraft should cruise close to
21375-463: The maximum altitude at which it can generate sufficient lift to maintain its altitude. As the aircraft's weight decreases throughout the flight, due to fuel burn, its optimum cruising altitude increases. In a piston engine , the decrease in pressure at higher altitudes can be mitigated by the installation of a turbocharger . Decreasing temperature at higher altitudes increases thermal efficiency . Since early 2006 until 2008, Scandinavian Airlines
21546-561: The more than five hundred 737s to be delivered in the year. The 737 MAX was grounded after two fatal crashes, Lion Air Flight 610 on October 29, 2018, and Ethiopian Airlines Flight 302 on March 10, 2019, in which a total of 346 people died. The day following the second crash, China became the first air authority to ground the aircraft, followed the next day by Australia, the European Union, India, Malaysia, Singapore, South Korea, and Turkey. The United States Federal Aviation Administration
21717-427: The most from winglets. They average a 6.69% increase in efficiency but depending on the route have a fuel savings distribution spanning from 4.6% to 10.5%. Airbus A319s see the most consistent fuel and emissions savings from winglets. Airbus A321s average a 4.8% improvement in fuel consumption, but have the widest swing based on routes and individual aircraft, recognizing anywhere from 0.2% improvement to 10.75%. As
21888-403: The most-active intercontinental market, the average fuel consumption in 2017 was 34 pax-km per L (2.94 L/100 km [80 mpg ‑US ] per passenger). The most fuel-efficient airline was Norwegian Air Shuttle with 44 pax-km/L (2.27 L/100 km [104 mpg ‑US ] per passenger), thanks to its fuel-efficient Boeing 787 -8, a high 85% passenger load factor and
22059-413: The older 737-200s P&W engines. The 737-500 has faced accelerated retirement due to its smaller size, after 21 years in service compared to 24 years for the -300. While a few 737-300s were slated for freighter conversion, no demand at all existed for a -500 freighter conversion. The 737-500 was replaced by the 737-600 of the Next Generation series, though the -600 was not as successful in total orders as
22230-500: The only major change. The MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers. The variant configuration with a predicted 5% lower trip cost and seat cost compared to the A321neo was firmed up by February 2018, and by mid-2018, the critical design review was completed. The MAX 10 has a similar capacity to the A321XLR, but shorter range and much poorer field performance in smaller airports. It
22401-631: The optimum airspeed , and economy is better at optimum altitudes , usually higher. An airline efficiency depends on its fleet fuel burn, seating density, air cargo and passenger load factor , while operational procedures like maintenance and routing can save fuel. Average fuel burn of new aircraft fell 45% from 1968 to 2014, a compounded annual reduction 1.3% with a variable reduction rate. In 2018, CO₂ emissions totalled 747 million tonnes for passenger transport, for 8.5 trillion revenue passenger kilometres (RPK), giving an average of 88 grams CO₂ per RPK; this represents 28 g of fuel per kilometre, or
22572-486: The original -200s and respectively -100s. The 737-200 Advanced became the production standard in June 1971. Boeing also provided the 737-200C ( Combi ), which allowed for conversion between passenger and cargo use and the 737-200QC (Quick Change), which facilitated a rapid conversion between roles. The 1,114th and last delivery of a -200 series aircraft was in August 1988 to Xiamen Airlines . Nineteen 737-200s, designated T-43 , were used to train aircraft navigators for
22743-459: The plug was not fully bolted into place during production; a subsequent FAA audit found many problems in the production process. In 2006, Boeing began to consider replacing the 737 with a "clean sheet" design that could follow the Boeing 787 Dreamliner . In June 2010, executives postponed the decision. On December 1, 2010, Boeing competitor Airbus launched the Airbus A320neo family , which offered better fuel economy and operating efficiency than
22914-453: The primary competitor for the 737NG series remained only the A320 family. The 737-600, the smallest model of the Next-Generation, was launched by Scandinavian Airlines (SAS) in March 1995 with the first aircraft delivered in September 1998. A total of 69 aircraft without winglets have been produced with the last one delivered to WestJet in 2006. The 737-600 replaced the 737-500 and is similar to
23085-482: The problem. In November, Boeing saw more than 1,000 order cancelations since the grounding in March 2019. Some of these already-built aircraft have seen their order canceled and Boeing is working to find new customers to take delivery. In late January 2022, Boeing's Chief Financial Officer said the 737 program was producing at a rate of 27 aircraft a month and was on track to ramp up the production. On March 4, Boeing reportedly had preliminary plans to ramp up production of
23256-512: The program's margins and cash generation for years. The rating agency also warned that the production halt would have wide and harmful impact to the whole aerospace and defense supply chain and the ramp-up would be slower than previously anticipated. CFM International reduced production of the LEAP-1B for the 737 MAX, in favor of the LEAP-1A for the Airbus A320neo, but was prepared to meet demand for both aircraft. Boeing did not publicly say how long
23427-467: The project. Faced with the record orders for Airbus and the defection of a long-time customer, on August 30, 2011, Boeing's board of directors approved the launch of the re-engined 737, which they said would meet or exceed the range of the Airbus A320neo while burning 4% less fuel. Studies for additional drag reduction were performed during 2011, including revised tail cone, natural laminar flow nacelle, and hybrid laminar flow vertical stabilizer. To focus on
23598-493: The re-engine project, Boeing abandoned the development of a new design under its Yellowstone Project. Firm configuration for the 737 MAX was scheduled for 2013. In March 2010, the estimated cost to re-engine the 737, according to Mike Bair, Boeing Commercial Airplanes' vice president of business strategy and marketing, would be US$ 2–3 billion , including the CFM engine development. During Boeing's Q2 2011 earnings call, CFO James Bell said
23769-404: The same 17-inch (43 cm) ground clearance of previous 737 engine nacelles . New struts and nacelles for the heavier engines add bulk, the main landing gear and supporting structure have been reinforced, and fuselage skins are thicker in some places—thus adding 6,500 pounds (2,900 kg) to the MAX 8's empty aircraft weight. To preserve fuel and payload capacity, its maximum takeoff weight
23940-527: The same month was approved by the European Union Aviation Safety Agency ( EASA ) on March 27, 2017. After completing 2,000 test flight hours and 180-minute ETOPS testing requiring 3,000 simulated flight cycles in April 2017, CFM International notified Boeing of a possible manufacturing quality issue with low pressure turbine (LPT) discs in LEAP-1B engines. Boeing suspended 737 MAX flights on May 4, and resumed flights on May 12. During
24111-450: The seats can be removed to carry cargo instead. There is a large door on the left side of the aircraft. The United States Navy was the launch customer for the 737-700C under the military designation C-40 Clipper . The 737-700ER (Extended Range ) was launched on January 31, 2006, and featured the fuselage of the 737-700 and the wings and landing gear of the 737-800. A 737-700ER can typically accommodate 126 passengers in two classes with
24282-442: The series has received 5,011 firm orders. In March 2019, civil aviation authorities around the world grounded the 737 MAX following two hull loss crashes which caused 346 deaths. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020, which was resumed in May 2020. In the midyear 2020, the FAA and Boeing conducted a series of recertification test flights. On November 18, 2020,
24453-405: The square of the speed in the drag equation . The form drag is minimized by having the smallest frontal area and by streamlining the aircraft for a low drag coefficient , while skin friction is proportional to the body's surface area, and can be reduced by maximizing laminar flow . Induced drag can be reduced by decreasing the size of the airframe , fuel and payload weight, and by increasing
24624-507: The suspension would last. The last pre-suspension fuselages entered final assembly in early January 2020. Boeing was reported to internally expect production to be halted for at least 60 days. Industry observers began to question if Boeing's projection of record production rate of 57 per month would ever be reached. In early April, the COVID-19 pandemic led Boeing to shut down its other airliner production lines and further delayed recertification of
24795-520: The three European short-haul single aisles slowly withdrew from the competition. Sales were low in the early 1970s and, after a peak of 114 deliveries in 1969, only 22 737s were shipped in 1972 with 19 in backlog. The US Air Force saved the program by ordering T-43s , which were modified Boeing 737-200s. African airline orders kept the production running until the 1978 US Airline Deregulation Act , which improved demand for six-abreast narrow-body aircraft. Demand further increased after being re-engined with
24966-456: The trans pacific routes, the average fuel consumption was 31 pax-km per L (3.23 L/100 km [73 mpg ‑US ] per passenger). The most fuel-efficient were Hainan Airlines and ANA with 36 pax-km/L (2.78 L/100 km [85 mpg ‑US ] per passenger) while Qantas was the least efficient at 22 pax-km/L (4.55 L/100 km [51.7 mpg ‑US ] per passenger). Key drivers for efficiency were
25137-405: The type. In late January 2020, production was expected to restart in April and take a year and a half to clear the inventory of 400 airplanes, ramping up slowly and building over time: Boeing might have delivered 180 stored jets by year-end and produce an equal number. Boeing did not disclose any possible effect on deliveries caused by the FAA's withdrawal of Boeing's delegated authority to certify
25308-435: The weight indirectly generates lift-induced drag, its minimization leads to better aircraft efficiency. For a given payload, a lighter airframe generates a lower drag. Minimizing weight can be achieved through the airframe's configuration, materials science and construction methods. To obtain a longer range, a larger fuel fraction of the maximum takeoff weight is needed, adversely affecting efficiency. The deadweight of
25479-652: The wingspan. (Wingspan is limited by the available width in the ICAO Aerodrome Reference Code .) Airbus installed wingtip fences on its planes since the A310-300 in 1985, and Sharklet blended-winglets for the A320 were launched during the November 2009 Dubai Airshow . Their installation adds 200 kilograms (440 lb) but offers a 3.5% fuel burn reduction on flights over 2,800 km (1,500 nmi). On average, among large commercial jets, Boeing 737-800s benefit
25650-507: Was Brazilian low-cost Gol on December 9. The first in the United States was American Airlines on December 29. Transport Canada and EASA both cleared the MAX in late January 2021, subject to additional requirements. Other regulators worldwide progressively ungrounded the aircraft, including those in the UAE , Australia , Kenya , and Brazil . The Indian Directorate General of Civil Aviation (DGCA) rescinded its ban on MAX airplanes in late August on
25821-400: Was US$ 4.0M (1968) ($ 35M today). The -200's unit cost was US$ 5.2M (1972) ($ 37.9M today). The 737-200 Advanced is an improved version of the -200, introduced into service by All Nippon Airways on May 20, 1971. After aircraft #135, the 737-200 Advanced has improved aerodynamics, automatic wheel brakes, more powerful engines, more fuel capacity, and hence a 15% increase in payload and range over
25992-450: Was designated the -300SP ( Special Performance ). The 737-300 was replaced by the 737-700 of the Next Generation series. The 737-400 was launched in 1985 to fill the gap between the 737-300 and the 757-200. In June 1986, Boeing announced the development of the 737-400, which stretched the fuselage a further 10 feet (3.0 m), increasing the capacity to 188 passengers, and requiring a tail bumper to prevent tailstrikes during take-off and
26163-478: Was designated the 737-200, with the original short-body aircraft becoming the 737-100. Detailed design work continued on both variants simultaneously. The first -100 was rolled out on January 17, 1967, and took its maiden flight on April 9, 1967, piloted by Brien Wygle and Lew Wallick. After several test flights the Federal Aviation Administration (FAA) issued Type Certificate A16WE certifying
26334-502: Was due to be retired in early 2023. As of September 2023 , a relatively high number of 737-200s remain in service compared to other early jet airliners, with fifty examples actively flying for thirty carriers. During the 737 MAX groundings , older 737s, including the 200 and Classic series , were in demand for leasing. C-GNLK, one of Nolinor's 737-200s, is the oldest jet airliner in commercial service as of 2024, having entered service 50 years prior in 1974. The Boeing 737 Classic
26505-414: Was due to enter service in April 2019. The 737 MAX 9, the stretched variant of the MAX 8, was launched with an order of 201 aircraft in February 2012. It made its roll-out on March 7, 2017, and first flight on April 13, 2017; It was certified by February 2018. The launch customer, Lion Air Group, took the first MAX 9 on March 21, 2018, before entering service with Thai Lion Air . The 737 MAX 9 replaced
26676-405: Was equipped with CFM56-7 high pressure ratio engines, a glass cockpit , and upgraded interior configurations. The four main models of the series can accommodate seating for 108 to 215 passengers. It was further developed into additional versions such as the corporate Boeing Business Jet (BBJ) and military P-8 Poseidon aircraft. Following the merger between Boeing with McDonnell Douglas in 1997,
26847-445: Was flying slower, from 860 to 780 km/h, to save on fuel costs and curb emissions of carbon dioxide. From 2010 to 2012, the most fuel-efficient US domestic airline was Alaska Airlines , due partly to its regional affiliate Horizon Air flying turboprops. In 2014, MSCI ranked Ryanair as the lowest-emissions-intensity airline in its ACWI index with 75 g CO 2 -e/ revenue passenger kilometre – below Easyjet at 82 g,
27018-410: Was included in the final spending bill. The U.S. Congress agreed in December 2022 on a bill allowing Boeing to certify the MAX 7 and MAX 10 without EICAS but required that the company must install a third angle-of-attack sensor in all 737 MAX types as previously demanded by European and Canadian regulators. The company also must install a switch to disable the stick shaker, which distracted pilots during
27189-553: Was introduced to meet the range and passenger capacity of the discontinued 757-200 and to directly compete with the Airbus A321 . The Boeing 737 MAX is the name given to the main models 737 MAX 7/8/9/10 series and the higher-density MAX 200 variant of the Boeing 737 family. It is offered in four main variants, typically offering 138 to 230 seats and a range of 3,215 to 3,825 nautical miles [nmi] (5,954 to 7,084 km; 3,700 to 4,402 mi). The 737 MAX 7, MAX 8 (including
27360-437: Was launched in December 2010 and reached 1,029 orders by June 2011, breaking Boeing's monopoly with American Airlines , which had an order for 130 A320neos that July. The 737 MAX had its first flight on January 29, 2016, and gained FAA certification on March 8, 2017. The first delivery was a MAX 8 on May 6, 2017, to Lion Air 's subsidiary Malindo Air , which put it into service on May 22, 2017. As of January 2019 ,
27531-457: Was matching fuel burn of the 737 MAX to that of the Airbus A320neo 's 15% fuel-burn advantage. The initial 737 MAX reduction was 10–12%; it was later enhanced to 14.5%. The fan was widened from 61 inches (150 cm) to 69.4 in (176 cm) by raising the nose gear and placing the engine higher on the wing and further forward. The split tip winglet added 1–1.5% fuel burn reduction and a re-lofted tail cone another 1%. Electronically controlling
27702-402: Was not a model delivered by Boeing and hence the nickname Special Freighter (SF) . Alaska Airlines was the first to convert one of their 400s from regular service to an aircraft with the ability to handle 10 pallets. The airline had also converted five more into fixed combi aircraft for half passenger and freight. These 737-400 Combi aircraft were retired in 2017 and replaced by the 737-700F of
27873-503: Was one of the last to ground the aircraft, defending against groundings by issuing a Continued Airworthiness Notice to operators on March 11, garnering criticism before finally grounding it on March 13, 2019. Contributing to the accidents was the Maneuvering Characteristics Augmentation System (MCAS), which activated unexpectedly due to erroneous angle of attack data, and inadequate pilot training. Investigations found Boeing did not fully inform operators about MCAS and found shortcomings in
28044-497: Was originally based on the 737-700, flying 1,000 nautical miles (1,900 km; 1,200 mi) farther and accommodating two more seat rows at 18% lower fuel costs per seat. The redesign uses the 737-8 wing and landing gear; a pair of over-wing exits rather than the single-door configuration; a 46-inch-longer (1,200 mm) aft fuselage and a 30-inch-longer (760 mm) longer forward fuselage; structural re-gauging and strengthening; and systems and interior modifications to accommodate
28215-450: Was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight Instrumentation System), and the passenger cabin incorporated improvements similar to those developed on the Boeing 757 . The prototype -300, the 1,001st 737 built, first flew on February 24, 1984, with pilot Jim McRoberts. It and two production aircraft flew a nine-month-long certification program. The 737-300 retrofitted with Aviation Partners ' winglets
28386-585: Was subsequently grounded worldwide from March 2019 to November 2020, with the FAA garnering criticism for being the last major authority to ground it. Investigations found Boeing did not fully inform operators about MCAS and found shortcomings in the FAA's certification process for the aircraft. The accidents and grounding cost Boeing an estimated US$ 20 billion in fines, compensation, and legal fees as of 2020, with indirect losses of more than US$ 60 billion from 1,200 cancelled orders . In 2021, Boeing paid US$ 2.5 billion in penalties and compensation to settle
28557-411: Was the company's largest source of profit. Around 80% of the 737 production costs involve payments to parts suppliers, which may be as low as US$ 10 million per plane. After the announcement, Moody's cut Boeing's debt ratings in December, citing the rising costs due to the grounding and the production halt including financial support to suppliers and compensation to airlines and lessors which could lower
28728-599: Was the second airline to put a 737 MAX into service, when it performed its first transatlantic flight with a MAX 8 named Sir Freddie Laker on July 15, 2017, between Edinburgh Airport in Scotland and Bradley International Airport in the U.S. state of Connecticut. Boeing aimed for 737 MAX to match the 99.7% dispatch reliability of the 737 Next Generation (NG). Southwest Airlines, the launch customer, took delivery of its first 737 MAX on August 29, 2017. Boeing planned to deliver at least 50 to 75 aircraft in 2017, 10–15% of
28899-624: Was unveiled in Boeing's Renton factory on November 22, 2019, and scheduled for first flight in 2020. Boeing also considered parallel development with the 757 replacement, similar to the development of the 757 and 767 in the 1970s. Fuel economy in aircraft The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft . Fuel efficiency is increased with better aerodynamics and by reducing weight , and with improved engine brake-specific fuel consumption and propulsive efficiency or thrust-specific fuel consumption . Endurance and range can be maximized with
29070-413: Was used for performance and engine testing: climb and landing performance, crosswind, noise, cold weather, high altitude, fuel burn and water-ingestion. Aircraft systems including autoland were tested with 1A003. 1A004, with an airliner layout, flew function-and-reliability certification for 300 hours with a light flight-test instrumentation. The 737 MAX 8 gained FAA certification on March 8, 2017, and in
29241-492: Was widely preferred over the -100 by airlines. The improved version, the 737-200 Advanced, was introduced into service by All Nippon Airways on May 20, 1971. The 737 original model with its variants, known later as the Boeing 737 Original , initially competed with SE 210 Caravelle and BAC-111 due to their earlier entry into service and later primarily with the McDonnell Douglas DC-9, then its MD-80 derivatives as
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