Boeing 737 MAX (23326959580) winglet.jpg
   HOME

TheInfoList



OR:

The Boeing 737 MAX is the fourth generation of the Boeing 737, a narrow-body airliner manufactured by
Boeing Commercial Airplanes Boeing Commercial Airplanes (BCA) is a division of The Boeing Company. It designs, assembles, markets, and sells jet airliners and business jets ( Boeing Business Jets), and also provides product-related maintenance and training to customers wor ...
. 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 a customer was a MAX 8 to
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
, 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 The CFM International LEAP ("Leading Edge Aviation Propulsion") is a high-bypass turbofan engine produced by CFM International, a 50–50 joint venture between American GE Aviation and French Safran Aircraft Engines (formerly Snecma). It is the ...
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 a range of . 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, , the MAX 7 and MAX 10 have not been certified, with the FAA declining to provide a timetable for approval. , the 737 MAX has 4,729 unfilled orders and 1,618 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, in which 346 people died. Contributing to the accidents was the Maneuvering Characteristics Augmentation System (MCAS), which activated unexpectedly due to erroneous
angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...
data, and remained active because of pilot error caused by inadequate training. The aircraft 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 Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...
process for the aircraft. The accidents and grounding cost Boeing an estimated in fines, compensation, and legal fees , with indirect losses of more than from 1,200 cancelled orders. In 2021, Boeing paid in penalties and compensation to
settle Settle or SETTLE may refer to: Places * Settle, Kentucky, United States * Settle, North Yorkshire, a town in England ** Settle Rural District, a historical administrative district Music * Settle (band), an indie rock band from Pennsylvania * ''S ...
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 European, or Europeans, or Europeneans, may refer to: In general * ''European'', an adjective referring to something of, from, or related to Europe ** Ethnic groups in Europe ** Demographics of Europe ** European cuisine, the cuisines of Europe ...
authorities followed in late January 2021. By December 2021, when
Chinese Chinese can refer to: * Something related to China * Chinese people, people of Chinese nationality, citizenship, and/or ethnicity **''Zhonghua minzu'', the supra-ethnic concept of the Chinese nation ** List of ethnic groups in China, people of va ...
authorities lifted their grounding, 180 of 195 countries had cleared 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 Alaska Airlines Flight 1282 was a scheduled domestic flight operated by Alaska Airlines from Portland International Airport in Portland, Oregon, to Ontario International Airport in Ontario, California. Shortly after takeoff on January 5, 2024, ...
, 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 the plug was not fully bolted into place during production; a subsequent FAA audit found many problems in the production process.


Development


Background

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 the 737, thanks to its engines: the LEAP from CFM International and the PW1000G from
Pratt & Whitney Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of Raytheon Technologies. Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially airlines) and military aviat ...
. In February 2011, Boeing CEO
Jim McNerney Walter James "Jim" McNerney Jr. (born August 22, 1949) is a business executive who was President and CEO of The Boeing Company, June 2005–July 2015. McNerney was also Chairman from June 2005 until March 1, 2016. McNerney oversaw development of ...
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 James Aaron Bell (born June 4, 1948) is a retired American executive of The Boeing Company. Bell is a retired president, executive vice president and chief financial officer of The Boeing Company. He served as interim president and chief execut ...
told investors that the company might re-engine the 737, but later that month Boeing Commercial Airplanes President James Albaugh said that 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 The Airbus A320 family is a series of narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, first flew on 22 February 1987, and was introduced in April 1988 by Air France. The first member of the famil ...
(current engine option), 130 A320neo, and 100 737NG. Officials also said they would order 100 re-engined 737s with CFM LEAP if Boeing pursued the project.


Program launch

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 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 , including the CFM engine development. During Boeing's Q2 2011 earnings call, CFO James Bell said the development cost for the airframe only would be 10–15% of the cost of a new program, which was estimated at at the time.
Bernstein Research AllianceBernstein Holding L.P. (AB) is a global asset management firm providing investment management and research services worldwide to institutional, high-net-worth and retail investors. AllianceBernstein's headquarters are located in Nashvill ...
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 , and closer to . Fuel consumption is reduced by 14% from the
737NG The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boein ...
.
Southwest Airlines Southwest Airlines Co., typically referred to as Southwest, is one of the major airlines of the United States and the world's largest low-cost carrier. It is headquartered in Dallas, Texas, and has scheduled service to 121 destinations in the U ...
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 a fuselage similar to the 737 though slightly larger, and would make use of the advanced composite technology developed for the
787 Dreamliner The Boeing 787 Dreamliner is an American wide-body jet airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, ...
. Boeing also considered a parallel development along with the
757 757 may refer to: * Boeing 757: a narrow-body airliner * AD 757: a year * 757 BC: a year * 757 (number): a number * Area code 757 Image:Area code 757.png, The area colored red indicates the southeast corner of Virginia served by area code 757 pol ...
replacement, similar to the development of the 757 and
767 767 may refer to: * Boeing 767, a jet airliner * 767 (number) * AD 767, a year in the 8th century. * 767 BC, a year in the 8th century BC * Area code 767 Area code 767 is the local telephone area code of the Commonwealth of Dominica, within the ...
in the 1970s.


Production

On August 13, 2015, the first 737 MAX fuselage completed assembly at
Spirit Aerosystems Spirit AeroSystems Holdings, Inc., based in Wichita, Kansas, is the world's largest first-tier aerostructures manufacturer. The company builds several important pieces of Boeing aircraft, including the fuselage of the 737, portions of the 787 fus ...
in Wichita, Kansas, for 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 GKN Ltd is a British multinational automotive and aerospace components business headquartered in Redditch, England. It is a long-running business known for many decades as Guest, Keen and Nettlefolds. It can trace its origins back to 1759 an ...
could not produce the titanium honeycomb inner walls for the
thrust reverser Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft ...
s quickly enough, Boeing switched to a composite part produced by Spirit to deliver 47 MAXs per month in 2017. Spirit supplies 69% of the 737
airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aerospa ...
, including the fuselage, thrust reverser, engine
pylons Pylon may refer to: Structures and boundaries * Pylon (architecture), the gateway to the inner part of an Ancient Egyptian temple or Christian cathedral * Pylon, a support tower structure for suspension bridges or highways * Pylon, an orange mar ...
, nacelles, and wing leading edges. A new spar-assembly line with robotic drilling machines was expected to increase throughput by 33%. The
Electroimpact Electroimpact is an aerospace engineering manufacturer founded by Peter Zieve in July 1986 and based in Mukilteo, Washington. History Electroimpact was founded by Peter Zieve in July 1986 in Seattle, Washington after he invented low voltage elect ...
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 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 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 Zhoushan , formerly romanized as Chusan, is an urbanized archipelago with the administrative status of a prefecture-level city in the eastern Chinese province of Zhejiang. It consists of an archipelago of islands at the southern mouth of H ...
, 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 the facility to Air China on December 15, 2018. The largest part of the suppliers cost are the
aerostructures An aerostructure is a component of an aircraft's airframe. This may include all or part of the fuselage, wings, or flight control surfaces. Companies that specialize in constructing these components are referred to as "aerostructures manufacturer ...
at (-% of the total), followed by the engines at (-%), systems and interiors at each (-%), then avionics at (-%).


Flight testing and certification

The 737 MAX gained its airworthiness approval based on the 737 legacy series (first approved on December 15, 1967), as 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 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 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 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.


Entry into service

The first delivery was a MAX 8, handed over to
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
(a subsidiary of Lion Air) on May 16, 2017; it entered service on May 22.
Norwegian Air International Norwegian Air International was an Irish airline and fully integrated subsidiary of Norwegian Air Shuttle, using its corporate identity. It operated flights to destinations in Europe and the Middle East from various European bases, and was headq ...
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 Sir Frederick Alfred Laker (6 August 1922 – 9 February 2006) was an English airline entrepreneur, best known for founding Laker Airways in 1966, which went bankrupt in 1982. Known as Freddie Laker, he was one of the first airline owners to a ...
'' 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 on August 29, 2017. Boeing planned to deliver at least to aircraft in 2017, 10–15% of the more than five hundred 737s to be delivered in the year.


Grounding and recertification

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 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 the FAA's
certification Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...
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 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 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 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 The National Transportation Safety Board (NTSB) is an independent U.S. government investigative agency responsible for civil transportation accident investigation. In this role, the NTSB investigates and reports on aviation accidents and incid ...
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 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 aviation and aerospace, foreign object debris (FOD), is any particle or substance, alien to an aircraft or system, which could potentially cause damage. External FOD hazards include bird strikes, hail, ice, sandstorms, ash-clouds or obje ...
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 Delegation is the assignment of authority to another person (normally from a manager to a subordinate) to carry out specific activities. It is the process of distributing and entrusting work to another person,Schermerhorn, J., Davidson, P., Poole ...
and invited global aviation stakeholders to comment on pending changes to 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 law, fraud is intentional deception to secure unfair or unlawful gain, or to deprive a victim of a legal right. Fraud can violate civil law (e.g., a fraud victim may sue the fraud perpetrator to avoid the fraud or recover monetary compens ...
in connection of both crashes of the 737 MAX, Boeing
settled A settler is a person who has migrated to an area and established a permanent residence there, often to colonize the area. A settler who migrates to an area previously uninhabited or sparsely inhabited may be described as a pioneer. Settle ...
by paying over in penalties and compensation: a criminal monetary penalty of $243.6 million, $1.77 billion in damages to airline customers, and $500 million to a fund for the families of crash victims.


Production slowdown and suspension

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 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 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 the program's margins and cash generation for years. The
rating agency A credit rating agency (CRA, also called a ratings service) is a company that assigns credit ratings, which rate a debtor's ability to pay back debt by making timely principal and interest payments and the likelihood of default. An agency may ra ...
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 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 the MAX.


Recertification and return to service

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, 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 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 Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, Kenya, and Brazil. The Indian Directorate General of Civil Aviation (DGCA) rescinded its ban on MAX airplanes in late August on 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 Required navigation performance (RNP) is a type of performance-based navigation (PBN) that allows an aircraft to fly a specific path between two 3D-defined points in space. Navigation precision Area navigation, Area navigation (RNAV) and RNP s ...
approaches with the MAX. In response to the recertification, some booking sites introduced tools allowing travelers to filter results to avoid flying on the type.


Production ramp-up and recovery

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 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 the company, Poland's
Enter Air Enter Air Sp. z o.o. is a Polish charter airline with its head office in Warsaw, Poland, and main base at Warsaw Chopin Airport and Katowice Airport. It operates holiday and charter flights out of its hubs in Poznań, Warsaw and Wrocław. His ...
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 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 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 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 Alaska Airlines Flight 1282 was a scheduled domestic flight operated by Alaska Airlines from Portland International Airport in Portland, Oregon, to Ontario International Airport in Ontario, California. Shortly after takeoff on January 5, 2024, ...
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, 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.


Certification of the MAX 7 and MAX 10

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, 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 An engine-indicating and crew-alerting system (EICAS) is an integrated system used in modern aircraft to provide aircraft flight crew with instrumentation and crew annunciations for aircraft engines and other systems. On EICAS equipped aircraft th ...
(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 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 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 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 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 the U.S. Congress held after the Alaska Airlines Flight 1282 accident. , Boeing estimated that the development, testing and validation of the fix to the anti-ice system would take an additional nine to 18 months. , 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, 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.


Design

In mid-2011, one design objective was matching fuel burn of the 737 MAX to that of the
Airbus A320neo The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
'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 to 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 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.


Aerodynamic changes

The 737 MAX uses a split-tip winglet, designed to reduce
vortex drag In aerodynamics, lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or ...
, which improves
fuel efficiency Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, wh ...
by maximizing lift, while staying in the same ICAO aerodrome reference code letter C gates as current Boeing 737s. It resembles a three-way hybrid of a blended winglet,
wingtip fence Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
, 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 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 at Mach 0.79. The new winglet has a total height of . Other improvements include a re-contoured
tail cone The tail is the section at the rear end of certain kinds of animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material ...
, 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 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.


Structural and other changes

The taller nose-gear strut maintains the same 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 to the MAX 8's empty aircraft weight. To preserve fuel and payload capacity, its maximum takeoff weight is heavier. Rockwell Collins was selected to supply four
liquid-crystal display A liquid-crystal display (LCD) is a flat-panel display A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipmen ...
s (LCD), as used on the 787, for the
glass cockpit A glass cockpit is an aircraft cockpit that features electronic (digital) flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. While a traditional cockpit relies on numerous mech ...
to improve pilots' situation awareness and efficiency. Boeing plans no major modifications for the 737 MAX flight deck, as it wants to maintain commonality with the 737 Next Generation family. Boeing Commercial Airplanes CEO Jim Albaugh said in 2011, that adding more fly-by-wire control systems would be "very minimal". However, the 737 MAX extended spoilers are fly-by-wire controlled. Most of the systems are carried from the 737NG to allow for a short differences-training course to upgrade flight crews. In addition to the Speed Trim System (STS), the automatic stabilizer control system has been enhanced to include MCAS. Compared to STS, MCAS has greater authority and cannot be disengaged with the aft and forward column cutout switches. The center console stabilizer-trim cutout switches have been re-wired. Unlike previous versions of the 737, the automatic stabilizer trim control functions cannot be turned off while retaining electric trim switches functionality. MCAS was deemed necessary by Boeing to meet its internal objective of minimizing training requirements for pilots already qualified on the 737NG. MCAS was to automatically mitigate the pitch-up tendency of the new flight geometry due to the engines being located farther forward and higher than on previous 737 models. During a reassessment of the aircraft in February 2020, both FAA and EASA determined that the stability and stall characteristics of the plane would have been acceptable with or without MCAS. As a production standard, the 737 MAX features the Boeing Sky Interior with overhead bins and LED lighting based on the Boeing 787's interior.


Engines

In 2011, the CFM LEAP-1B engine was initially 10–12% more efficient than the previous CFM56-7B of the 737NG. The 18-blade, woven carbon-fiber fan enables a 9:1 bypass ratio (up from 5.1:1 with the previous 24-blade titanium fan) for a 40% smaller noise footprint. The CFM56 bypass ranges from 5.1:1 to 5.5:1. The two- spool design has a low-pressure section comprising the fan and three booster stages driven by five axial turbine stages and a high-pressure section with a 10-stage
axial compressor An axial compressor is a gas compressor that can continuously pressurize gases. It is a rotating, airfoil-based compressor in which the gas or working fluid principally flows parallel to the axis of rotation, or axially. This differs from other ...
driven by a two-stage turbine. The 41:1 overall pressure ratio increased from 28:1, and advanced hot-section materials enabling higher operating temperatures permit a 15% reduction in thrust-specific fuel consumption (TSFC), along with 20% lower carbon emissions, 50% lower nitrogen-oxide emissions, though each engine weighs more at . In August 2011, Boeing had to choose between or fan diameters, necessitating landing gear changes to maintain a ground clearance beneath the new engines; Boeing Commercial Airplanes chief executive officer Jim Albaugh stated "with a bigger fan you get more efficiency because of the bypass ratio ut alsomore weight and more drag", with more airframe changes. In November 2011, Boeing selected the larger fan diameter, necessitating a longer nose landing gear. In May 2012, Boeing further enlarged the fan to , paired with a smaller engine core within minor design changes before the mid-2013 final configuration. The nacelle features chevrons for noise reduction like the 787. A new bleed air digital regulator will improve its reliability. The new nacelles being larger and more forward possess aerodynamic properties which act to further increase the pitch rate. The larger engine is cantilevered ahead of and slightly above the wing, and the
laminar flow In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mi ...
engine nacelle lipskin is a GKN Aerospace one-piece, spun-formed aluminum sheet inspired by the 787.


Operational history

After one year of service, 130 MAXs had been delivered to 28 customers, logging over 41,000flights in 118,000hours and flying over 6.5million passengers. Flydubai observed 15% more efficiency than the NG, more than the 14% promised, and dependability reached 99.4%. Long routes include 24 over , including a daily Aerolíneas Argentinas service from Buenos Aires to Punta Cana over . In 2019, Moody's had estimated Boeing's operating margin to be for each 737 MAX 8 at its list price of $121.6 million (~$ in ), although the list price is usually discounted 50–55% in practice. This high margin was made possible by the efficiencies of production volume and the amortization of development costs and capital investment over the decades of the program run. However, costs have since risen significantly and the margin reduced following the two crashes, the FAA grounding, and the severe disruption to production. Boeing estimated it would cost an additional $6.3 billion to produce the remaining 737 MAX program, $4 billion for "future abnormal costs" as production restarted, plus an estimated $8.3 billion for concessions and compensation to customers. The rising costs also led Moody's to downgrade Boeing's credit rating.


Variants

The 737-700, -800 and -900ER, the most widespread versions of the previous 737NG, are succeeded by the 737 MAX 7, MAX 8 and MAX 9, respectively (FAA type certificate and marketing designation (since 2020): ''737-7'', ''-8'', and ''-9''). The 737 MAX 8 entered service in May 2017, the MAX 9 entered service in March 2018, and the MAX 200 (a high-density version of the MAX 8) entered service in June 2021. Deliveries for the MAX 7 and the MAX 10 are expected to begin in 2024, after years of delays. In February 2018, Boeing forecast that 60–65% of demand for the airliner would be for the 737 MAX 8 variant, 20–25% for the MAX 9 and MAX 10, and 10% for the MAX 7.


737 MAX 7

At the July 2016
Farnborough Air Show The Farnborough Airshow, officially the Farnborough International Airshow, is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors. Since its fir ...
, Boeing announced that the MAX 7, originally based on the 737-700, will accommodate two more seat rows than the 737-700 for 138 seats. Compared to the 737-700, the MAX 7 has a pair of over-wing exit doors rather than the single-door, a 46-inch longer aft fuselage and a 30-inch longer forward fuselage, structural re-gauging and strengthening, and systems and interior modifications to accommodate the longer length. The MAX 7 uses the same wing and landing gear as the MAX 8. It is expected to fly farther than the -700 with 18% lower fuel costs per seat. Boeing predicts that the MAX 7 will carry 12 more passengers farther than A319neo with seven percent lower operating costs per seat. Production on the first wing spar for the 737-7 began in October 2017. Assembly of the first flight-test aircraft began on November 22, 2017, and was rolled out of the factory on February 5, 2018. The MAX 7 took off for its first flight on March 16, 2018, from the factory in
Renton, Washington Renton is a city in King County, Washington, and an inner-ring suburb of Seattle. Situated southeast of downtown Seattle, Renton straddles the southeast shore of Lake Washington, at the mouth of the Cedar River. As of the 2020 census, the ...
, and flew for three hours over Washington state. It reached and , performed a low
approach Approach may refer to: Aviation *Visual approach *Instrument approach *Final approach Music * ''Approach'' (album), by Von Hertzen Brothers * ''The Approach'', an album by I:Scintilla Other uses *Approach Beach, a gazetted beach in Ting Kau, Ho ...
, systems checks and an inflight engine restart, and landed at Boeing's flight test center in Moses Lake, Washington. Entry into service with launch operator
Southwest Airlines Southwest Airlines Co., typically referred to as Southwest, is one of the major airlines of the United States and the world's largest low-cost carrier. It is headquartered in Dallas, Texas, and has scheduled service to 121 destinations in the U ...
was originally expected in January 2019, however, it has been repeatedly delayed. Southwest had ordered a total of 234 MAX 7s. WestJet also ordered 22 MAX 7s, but later converted those into MAX 8s amid the delays. In 2022, Southwest announced that it would take early delivery of its MAX 8 orders to make up for the delay of the MAX 7. , Southwest has removed the MAX 7 from future fleet planning, however, the company said that it remained committed to the type, and was willing to wait until 2026 or 2027 for first delivery.


737 MAX 8

The first variant developed in the 737 MAX series; the MAX 8 replaces the 737-800 with a longer fuselage than the MAX 7. In 2016, Boeing planned to improve its range from to after 2021. On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8. The MAX 8 has a lower empty weight and higher maximum takeoff weight than the A320neo. During a test flight conducted for ''Aviation Week'', while cruising at a true airspeed of and a weight of , at a lower than optimal altitude (FL350 vs. the preferred FL390) and with an "unusually far forward" center of gravity, the test aircraft consumed of fuel per hour. The Boeing 737 MAX 8 completed its first flight test in
La Paz La Paz (), officially known as Nuestra Señora de La Paz (Spanish pronunciation: ), is the seat of government of the Bolivia, Plurinational State of Bolivia. With an estimated 816,044 residents as of 2020, La Paz is the List of Bolivian cities ...
, Bolivia. The altitude at
El Alto International Airport El Alto International Airport ( es, link=no, Aeropuerto Internacional El Alto) is an international airport serving La Paz, Bolivia. It is located in the city of El Alto, west of La Paz. At an elevation of , it is the highest international air ...
tested the MAX's capability to take off and land at high altitudes. Its first commercial flight was operated by
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
on May 22, 2017, between Kuala Lumpur and Singapore as Flight OD803. In early 2017, a new MAX 8 was valued at $52.85million, rising to below $54.5million by mid2018.


737 MAX 200

In September 2014, Boeing launched a high-density version of the 737 MAX 8, the 737 MAX 200 or 737–8–200, named for seating for up to 200 passengers in a single-class high-density configuration with slimline seats; an extra pair of exit doors is required because of the higher passenger capacity. Boeing states that this version would be 20% more cost-efficient per seat than current 737 models and would be the most efficient narrow-body on the market when delivered, including 5% lower operating costs than the 737 MAX 8. Three of eight service trolleys are removed to accommodate more passenger space. An order with
Ryanair Ryanair is an Irish ultra low-cost carrier founded in 1984. It is headquartered in Swords, Dublin, Ireland and has its primary operational bases at Dublin and London Stansted airports. It forms the largest part of the Ryanair Holdings family ...
for 100 aircraft was finalized in December 2014. In mid-November 2018, the first of then 135 ordered by Ryanair rolled out, in a 197-seat configuration. It was first flown from Renton on January 13, 2019, and was due to enter service in April 2019, with another four MAX 200s expected later in 2019, though certification and deliveries were deferred while the MAX was grounded. In November 2019, Ryanair informed its pilots that, due to an unspecified design issue with the additional over-wing exit doors, it did not expect to receive any MAX 200s until late April or early May 2020. In 2020, at the height of the COVID travel slump, Ryanair renegotiated its order and purchased an additional 75 MAX 200 aircraft at one-third of the list price. The high-density variant was certified by the FAA on March 31, 2021. Ryanair took delivery of its first MAX 200 in June 2021. Besides launch customer Ryanair, other customers include International Airlines Group and low-cost airlines
Akasa Air Akasa Air, a brand of SNV Aviation Private Limited, is an Indian low-cost airline headquartered in Mumbai, Maharashtra, India. It was founded by Vinay Dube and Aditya Ghosh with investor Rakesh Jhunjhunwala holding a 46% stake in the airline. T ...
of India, Allegiant Air of the US,
Arajet Arajet S.A. is an ultra low-cost startup airline based in Santo Domingo, Dominican Republic. Operations began on the 15th of September, 2022, with a flight to Barranquilla, Colombia. History Early operations In late 2014, Dominican Wings rec ...
of the Dominican Republic and Vietnam's VietJet.


Proposed 737-8ERX

Airlines have been shown a 737-8ERX concept based on the 737 MAX 8 with a higher maximum take-off weight and a longer range of using the wings, landing gear, and central section from the MAX 9. The range of this aircraft would be closer to the
Airbus A321LR The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
, although with a smaller 150 seat capacity.


737 MAX 9

The 737 MAX 9 replaces the 737-900 and has a longer fuselage than the MAX 8. In 2016, Boeing planned to improve its range from to after 2021. Lion Air was the launch customer with an order for 201 in February 2012. It made its roll-out on March 7, 2017, and first flight on April 13, 2017; it took off from Renton Municipal Airport and landed at Boeing Field after a 2 hr 42 min flight. It was presented at the 2017 Paris Air Show. Boeing 737 MAX 9 flight tests were scheduled to run through 2017, with 30% of the -8 tests repeated; aircraft 1D001 was used for auto-land, avionics, flutter, and mostly stability-and-control trials, while 1D002 was used for environment control system testing. It was certified by February 2018. Asian low-cost carrier Lion Air Group took delivery of the first MAX 9 on March 21, 2018, before entering service with Thai Lion Air. As the competing Airbus A321neo attracts more orders, the sale value of a 737 MAX 9 is the same as a 2018 MAX 8 at $53million (~$ in ).


737 MAX 10

Loyal customers, such as Korean Air and United Airlines, pressed Boeing to develop a variant larger than the MAX 9 in order to compete with the Airbus A321neo, of which Boeing revealed studies in early 2016. As the Airbus A321neo had outsold the MAX 9 five-to-one, the proposed MAX 10 included a larger engine, stronger wings, and telescoping landing gear in mid-2016. In September 2016, it was reported that the variant would be simpler and lower-risk, with a modest stretch of for a length of , seating 12–18 more passengers for 192–198 in a dual-class layout or 226-232 for a single class, needing an uprated LEAP-1B that could be available by 2019 or 2020, and would likely require a landing-gear modification to move the
rotation Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...
point slightly
aft "Aft", in nautical terminology, is an adjective or adverb meaning towards the stern (rear) of the ship, aircraft or spacecraft, when the frame of reference is within the ship, headed at the fore. For example, "Able Seaman Smith; lie aft!" or "Wh ...
. In October 2016, Boeing's board of directors granted authority to offer the stretched variant with two extra fuselage sections forward and aft with a range, reduced from the range of the MAX 9. In early 2017, Boeing showed a stretch to , enabling seating for 230 in a single class or 189 in two-class capacity, compared to 193 in two-class seating for the A321neo. The modest stretch of the MAX 10 enables the aircraft to retain the existing wing, and the Leap 1B engine from the MAX 9 with a trailing-link main landing gear as the only major change. Boeing 737 MAX Vice President and General Manager Keith Leverkuhn said the design had to be frozen in 2018, for a 2020 introduction. Boeing hopes that 737 operators and 737 MAX customers like United Airlines, Delta Air Lines, Alaska Airlines, Air Canada, Lion Air, and Chinese airlines will be interested in the new variant. Boeing predicts a 5% lower trip cost and seat cost compared to the A321neo. Air Lease Corporation wants it a year sooner; its CEO John Pleuger stated, "It would have been better to get the first airplane in March 2019, but I don't think that's possible." AerCap CEO Aengus Kelly is cautious and said the -9 and -10 "will cannibalize each other". The 737 MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers. United Airlines will be the largest 737 MAX 10 customer, converting 100 of their 161 orders for the MAX 9 into orders for the MAX 10. Boeing ended the 2017 Paris Air Show with 361 orders and commitments, including 214 conversions, from 16 customers, including 50 orders from Lion Air. The variant configuration was firmed up by February 2018, and by mid-2018, the critical design review was completed. , assembly was underway with a first flight planned for late 2019. The semi-levered landing gear design has a telescoping oleo-pneumatic strut with a down-swinging lever to permit taller gear. Driven by the existing retraction system, a shrink-link
mechanical linkage A mechanical linkage is an assembly of systems connected to manage forces and movement. The movement of a body, or link, is studied using geometry so the link is considered to be rigid. The connections between links are modeled as providing i ...
mechanism at the top of the leg, inspired by
carrier aircraft Carrier-based aircraft, sometimes known as carrier-capable aircraft or carrier-borne aircraft, are naval aircraft designed for operations from aircraft carriers. They must be able to launch in a short distance and be sturdy enough to withstand ...
designs, allows the gear to be drawn in and shortened while being retracted into the existing
wheel well Fender is the American English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well (the fender underside). Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thr ...
. Entry into service was slated for July 2020. On November 22, 2019, Boeing unveiled the first MAX 10 to employees in its Renton factory, Washington, scheduled for the first flight in 2020. At the time, 531 MAX 10s were on order, compared to the 3142 Airbus A321neos sold, capable of carrying 244 passengers or to fly up to in its heaviest
A321XLR The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
variant. The MAX 10 has similar capacity as the A321XLR, but shorter range and much poorer field performance, greatly hindering its potential to service smaller airports as compared to the A321XLR. By early 2021, Boeing expected 737 MAX 10 deliveries to start in 2023. The variant made its maiden flight on June 18, 2021, initiating its flight test and certification program. On June 29, 2021, United Airlines placed an order for another 150 of the Boeing 737 MAX 10. These MAX 10 will replace a large number of United's older
Boeing 757-200 The Boeing 757 is an American Narrow-body aircraft, narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the Boeing 727, 727 (a trijet), received its first orders in August 1978. ...
s. In January 2024, United CEO Kirby noted in an interview that the airline was in the process of developing plans that did not include the MAX 10 in its future fleet. In September 2021,
Ryanair Ryanair is an Irish ultra low-cost carrier founded in 1984. It is headquartered in Swords, Dublin, Ireland and has its primary operational bases at Dublin and London Stansted airports. It forms the largest part of the Ryanair Holdings family ...
failed to reach an agreement with Boeing over an order of MAX 10s, citing cost as a primary concern. However, in May 2023, Ryanair announced the order of 150 MAX 10s and an option to purchase a further 150. In November 2022, Boeing Commercial Airplanes CEO Stanley Deal told investors at a conference that the MAX 10 was expected to enter service in 2024. By October 2023, deliveries were anticipated in early 2025.


Boeing Business Jet

The BBJ MAX 8 and BBJ MAX 9 are business jet variants of the 737 MAX 8 and 9, with new CFM LEAP-1B engines and advanced winglets providing 13% better fuel burn than the
Boeing Business Jet Boeing Business Jets (BBJ) are versions of Boeing's jet airliners with modifications to serve the private, head of state and corporate jet market. In 1996, Phil Condit, president of The Boeing Company, and Jack Welch, chairman and CEO of Genera ...
; the BBJ MAX 8 has a range, and the BBJ MAX 9 a range. The BBJ MAX 7 was unveiled in October 2016, with a range and 10% lower operating costs than the original BBJ, while being larger. The BBJ MAX 8 first flew on April 16, 2018, before delivery later the same year, and has a range of with an auxiliary fuel tank.


Operators

, the five largest operators of the Boeing 737 MAX were
Southwest Airlines Southwest Airlines Co., typically referred to as Southwest, is one of the major airlines of the United States and the world's largest low-cost carrier. It is headquartered in Dallas, Texas, and has scheduled service to 121 destinations in the U ...
(207), United Airlines (145), Ryanair Holdings (126), Alaska Airlines (62), and American Airlines (54).


Orders and deliveries

American Airlines was the first disclosed customer. By November 17, 2011, there were 700 commitments from nine customers, including Lion Air and SMBC Aviation Capital. By December 2011, the 737 MAX had 948 commitments and firm orders from thirteen customers. On September 8, 2014, Ryanair agreed to 100 firm orders with 100 options. In January 2017, aircraft leasing company GECAS ordered 75. By January 2019 the 737 MAX had 5,011 firm orders from 78 identified customers, with the top three being Southwest Airlines with 280, flydubai with 251, and Lion Air with 251. The first 737 MAX 8 was delivered to
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
on May 16, 2017. Following the groundings in March 2019, Boeing suspended all deliveries of 737 MAX aircraft, reduced production from 52 to 42 aircraft per month, and on December 16, 2019, announced that production would be suspended from January 2020 to conserve cash. At the time of the grounding, the 737 MAX had 4,636 unfilled orders valued at an estimated $600billion. Boeing produced over 450 MAX aircraft awaiting delivery, about half of which are expected to be delivered in 2021, and the majority of the remainder in 2022. By November 30, 2020, at the time of the ungrounding, the unfilled orders stood at 4,039 aircraft. In November 2021, during the Dubai Airshow, Boeing received 72 firm orders from a new 737 MAX customer, India based
Akasa Air Akasa Air, a brand of SNV Aviation Private Limited, is an Indian low-cost airline headquartered in Mumbai, Maharashtra, India. It was founded by Vinay Dube and Aditya Ghosh with investor Rakesh Jhunjhunwala holding a 46% stake in the airline. T ...
, to be fulfilled over a 4-year period with first delivery in June 2022. In late January 2022 Boeing was working to clear the remaining inventory of 335 MAX aircraft and estimated most of them would be delivered by the end of 2023. In December 2022, the 1000th 737 MAX was delivered. In July 2023, Boeing first revealed the 737 MAX sub-type orders as follows: 2,751 MAX 8 (63%), 810 MAX 10 (19%), 344 MAX 200 (8%), 297 MAX 7 (7%), and 137 MAX 9 (3%). , the 737 MAX has 4,729 unfilled orders and 1,618 deliveries.


Accidents and incidents

As of 2023, the 737 MAX series had experienced 1.48 fatal hull loss accidents for every million takeoffs.


Lion Air Flight 610

On October 29, 2018, Lion Air Flight 610, a 737 MAX 8, crashed into the
Java Sea The Java Sea ( id, Laut Jawa, jv, Segara Jawa) is an extensive shallow sea on the Sunda Shelf, between the Indonesian islands of Borneo to the north, Java to the south, Sumatra to the west, and Sulawesi to the east. Karimata Strait to its nort ...
13 minutes after takeoff from Soekarno–Hatta International Airport, Jakarta, Indonesia. The flight was a scheduled domestic flight to
Depati Amir Airport Depati Amir Airport ( id, Bandar Udara Depati Amir) also known as Pangkal Pinang Airport, is an airport in Indonesia located in Pangkal Pinang on Bangka Island, part of Bangka Belitung Islands province. The airport has been managed by PT. Angk ...
, Pangkal Pinang, Indonesia. All 189 people on board died. This was the first fatal aviation crash and first hull loss of a 737 MAX. The aircraft had been delivered to Lion Air two months earlier. People familiar with the investigation reported that during a flight piloted by a different crew on the day before the crash, the same aircraft experienced a similar malfunction but an extra pilot sitting in the cockpit jumpseat correctly diagnosed the problem and told the crew how to disable the malfunctioning MCAS flight-control system. Indonesia's National Transportation Safety Committee released its final report into the crash on October 25, 2019, attributing the crash to the MCAS pushing the aircraft into a
dive Diving most often refers to: * Diving (sport), the sport of jumping into deep water * Underwater diving, human activity underwater for recreational or occupational purposes Diving or Dive may also refer to: Sports * Dive (American football), a ...
due to data from a faulty angle-of-attack sensor. Following the Lion Air crash, Boeing issued an operational manual guidance, advising airlines on how to address erroneous cockpit readings.


Ethiopian Airlines Flight 302

On March 10, 2019, Ethiopian Airlines Flight 302, operated by a four-month-old 737 MAX 8, crashed approximately six minutes after takeoff from Addis Ababa, Ethiopia, on a scheduled flight to Nairobi, Kenya, killing all 149 passengers and 8 crew members. The cause of the crash was initially unclear, though the aircraft's vertical speed after takeoff was reported to be unstable. Evidence retrieved on the crash site suggests, that at the time of the crash, the aircraft was configured to dive, similar to Lion Air Flight 610. The similarity of the physical and flight data evidence from the accidents led to the global
737 MAX groundings The Boeing 737 MAX passenger airliner was grounded worldwide between March 2019 and December 2020longer in many jurisdictionsafter 346 people died in two crashes: Lion Air Flight 610 on October 29, 2018 and Ethiopian Airlines Flight 302 on Mar ...
beginning on the day of the second accident.


Alaska Airlines Flight 1282

On January 5, 2024,
Alaska Airlines Flight 1282 Alaska Airlines Flight 1282 was a scheduled domestic flight operated by Alaska Airlines from Portland International Airport in Portland, Oregon, to Ontario International Airport in Ontario, California. Shortly after takeoff on January 5, 2024, ...
, a 737 MAX 9, suffered an uncontrolled decompression shortly after takeoff from Portland International Airport.Yoon, John
"Alaska Airlines Plane Forced to Land at Oregon Airport Shortly After Takeoff"
'' The New York Times'', January 5, 2024. Retrieved January 5, 2024.
The MAX 9, like the
737-900ER The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boein ...
, features a rear mid-cabin exit door on each side behind the wings that is required when used with dense seating configurations. On less densely configured aircraft, those exit doors are not required and door plugs are installed in their place, as was the case on this aircraft. During the climb, a door plug blew out, causing the decompression. The plane returned to
Portland Portland most commonly refers to: * Portland, Oregon, the largest city in the state of Oregon, in the Pacific Northwest region of the United States * Portland, Maine, the largest city in the state of Maine, in the New England region of the northeas ...
, and there were no fatalities or significant injuries among the 171 passengers and 6 crew on board. Some small personal belongings, along with cabin trim such as seat covers and headrests, were sucked out of the opening. According to some passengers, a child seated nearby had his shirt pulled off and sucked out of the aircraft while his mother held him. The FAA, Boeing, Alaska Airlines, and the NTSB quickly acknowledged the accident and an investigation was launched. As a precautionary measure, Alaska Airlines grounded their 737 MAX 9 fleet."Alaska Airlines grounds Boeing 737 Max 9 planes after mid-air window blowout"
theguardian.com, January 6, 2024.
Hours later, the FAA ordered the grounding and inspection of 171 aircraft from the global 737 MAX 9 fleet with similar configuration to the incident aircraft, along with corrective action if necessary. Alaska Airlines and United Airlines both reported finding loose door plug bolts on some of the aircraft inspected. On February 5, 2024, the NTSB said in its preliminary report that the four key bolts that should have secured the door plug were not installed on the accident aircraft as delivered to Alaska Airlines by Boeing following opening the door plug at Boeing's Renton factory to repair damaged rivets.


Southwest Airlines Flight 746

In May 2024, US authorities were investigating an incident which occurred on Southwest Airlines Flight 746 from Phoenix to Oakland. The MAX airliner experienced
Dutch roll Dutch roll is a type of aircraft motion consisting of an out-of-phase combination of "tail-wagging" (yaw) and rocking from side to side (roll). This yaw-roll coupling is one of the basic flight dynamic modes (others include phugoid, short per ...
and some damage to the rudder standby power control unit was reported.


Specifications


See also

*
Financial impact of the Boeing 737 MAX groundings The have had a deep financial effect on the aviation industry and a significant effect on the national economy of the United States. No airline took delivery of the MAX during the groundings. Boeing slowed MAX production to 42 aircraft per mont ...


Notes


References


Further reading

* * *


External links

* * * {{Boeing 7x7 timeline Aircraft first flown in 2016 737 MAX Low-wing aircraft Twinjets 2010s United States airliners Corporate controversies