Boeing 737 MAX

Boeing 737 MAX
A WestJet Boeing 737 MAX 8 on final approach
The 737 MAX is a fourth generation Boeing 737, re-engined with CFM LEAP turbofans.
Role Narrow-body twin-engine jet airliner
National origin United States
Manufacturer Boeing Commercial Airplanes
First flight January 29, 2016[1]
Introduction May 22, 2017 with Malindo Air[2]
Status Flight testing, grounded from commercial use
Primary users Southwest Airlines
American Airlines
Air Canada
China Southern Airlines
Produced 2014[3]-present[a]
Number built 387 delivered to customers as of March 2019[5]
approx. 400 produced and stored as of Dec. 2019[6]
Program cost Airframe only: $1–1.8 billion; including engine development: $2–3B[7]
Unit cost
MAX 7: US$99.7  million
MAX 8: US$121.6M
MAX 200: US$124.8M
MAX 9: US$128.9M
MAX 10: US$134.9M as of 2019 [8]
Developed from Boeing 737 Next Generation

The Boeing 737 MAX is the fourth generation of the Boeing 737, a narrow-body airliner manufactured by Boeing Commercial Airplanes (BCA). It succeeds the Boeing 737 Next Generation (NG). It is based on earlier 737 designs, with more efficient CFM International LEAP-1B engines, aerodynamic changes including its distinctive split-tip winglets, and airframe modifications.[9]

The new series was publicly announced on August 30, 2011.[10] It took its maiden flight on January 29, 2016[1] and gained FAA certification in March 2017.[11][9] The first delivery was a MAX 8 in May 2017, to Malindo Air,[12] with whom it commenced service on May 22, 2017.[2]

The 737 MAX series has been offered in four variants, offering 138 to 204 seats in typical two-class configuration[13] and a 3,215 to 3,825 nmi (5,954 to 7,084 km) range. The 737 MAX 7, MAX 8 (including the denser, 200–seat MAX 200), and MAX 9 are intended to replace the 737-700, -800, and -900, respectively.[9] Additional length is offered with the further stretched 737 MAX 10. As of December 2019, the Boeing 737 MAX had received 4,932 firm orders and delivered 387 aircraft.[5]

In the aftermath of two fatal accidents, Lion Air Flight 610 and Ethiopian Airlines Flight 302, the 737 MAX was grounded worldwide in March 2019.[14] Boeing implemented changes to its flight control system and pilot training, and expected the airliner to be flying again by mid-2020.[15] Boeing subsequently suspended production in January 2020 with approximately 400 MAX airplanes awaiting delivery;[16] production resumed in May 2020 at a low rate.[4] Between June 29 and July 1, 2020, the FAA and Boeing conducted a series of recertification test flights. Several key tasks remain before the grounding order can be lifted.[17]



In 2006, Boeing started considering the replacement of the 737 with a "clean-sheet" design that could follow the Boeing 787 Dreamliner.[18] In June 2010, a decision on this replacement was postponed into 2011.[19]

On December 1, 2010, Boeing's competitor, Airbus, launched the Airbus A320neo family to improve fuel burn and operating efficiency with new engines: the CFM International LEAP and Pratt & Whitney PW1000G.[20] In February 2011, Boeing's CEO Jim McNerney maintained "We're going to do a new airplane."[21] In March 2011, BCA President James Albaugh told participants of a trade meeting the company was not sure about a 737 re-engine, like Boeing CFO James A. Bell stated at an investor conference the same month.[22] The A320neo gathered 667 commitments at the June 2011, Paris Air Show for a backlog of 1,029 units since its launch, setting an order record for a new commercial airliner.[23]

On July 20, 2011, American Airlines announced an order for 460 narrowbody jets including 130 A320ceos and 130 A320neos, and intended to order 100 re-engined 737s with CFM LEAPs, pending Boeing confirmation.[24] The order broke Boeing's monopoly with the airline and forced Boeing into a re-engined 737.[25] As this sale included a Most-Favoured-Customer Clause, Airbus has to refund any difference to American if it sells to another airline at a lower price, so the European manufacturer cannot give a competitive price to competitor United Airlines, leaving it to a Boeing-skewed fleet.[26]

Program launch

737 MAX 9 mockup at 2012 ILA Berlin

On August 30, 2011, Boeing's board of directors approved the launch of the re-engined 737, expecting a fuel burn 4% lower than the A320neo.[10] Studies for additional drag reduction were performed during 2011, including revised tail cone, natural laminar flow nacelle, and hybrid laminar flow vertical stabilizer.[27] Boeing abandoned the development of a new design.[28] Boeing expected the 737 MAX to meet or exceed the range of the Airbus A320neo.[29] Firm configuration for the 737 MAX was scheduled for 2013.[30]

In March 2010, the estimated cost to re-engine the 737 according to Mike Bair, Boeing Commercial Airplanes' vice president of business strategy & marketing, would be $2–3 billion including the CFM engine development. During Boeing's Q2 2011 earnings call, former CFO James Bell said the development cost for the airframe only would be 10–15% of the cost of a new program estimated at $10–12 billion at the time. Bernstein Research predicted in January 2012, that this cost would be twice that of the Airbus A320neo.[7] The MAX development cost could have been well over the $2bn internal target and closer to $4bn.[31] Fuel consumption is reduced by 14% from the 737NG.[32]

In November 2014, Boeing Chief Executive Officer Jim McNerney said the 737 will be replaced by a new airplane by 2030, slightly bigger and with new engines but keeping its general configuration, probably a composite airplane.[33]


Roll-out of the first Boeing 737 MAX in December 2015

On August 13, 2015, the first 737 MAX fuselage completed assembly at Spirit Aerosystems in Wichita, Kansas, for a test aircraft that would eventually be delivered to launch customer Southwest Airlines.[34] On December 8, 2015, the first 737 MAX—a MAX 8 named Spirit of Renton—was rolled out at the Boeing Renton Factory.[35][36]

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 the 737 airframe, including the fuselage, thrust reverser, engine pylons, nacelles, and wing leading edges.[37]

A new spar-assembly line with robotic drilling machines should increase throughput by 33%. The Electroimpact automated panel assembly line sped up the wing lower-skin assembly by 35%.[38] Boeing planned to increase its 737 MAX monthly production rate from 42 planes in 2017, to 57 planes by 2019.[39] The new spar-assembly line is designed by Electroimpact.[40] Electroimpact has also installed fully automated riveting machines and tooling to fasten stringers to the wing skin.[41]

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.[42] 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.[43]

On September 23, 2015, Boeing announced a collaboration with Commercial Aircraft Corporation of China Ltd. to build a completion and delivery facility for the 737,[44] in Zhoushan, China,[45] the first outside the U.S.[46] 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.[47]

The largest part of the suppliers cost are the aerostructures with US$10–12M (35-34% of the US$ 28.5-35 M total), followed by the engines with US$7–9M (25-26%), systems and interiors with US$5–6M each (18-17%), then avionics with US$1.5-2M (5-6%).[48]

Flight testing and certification

The first flight took place on January 29, 2016, at Renton Municipal Airport,[49] nearly 49 years after the maiden flight of the original 737-100, on April 9, 1967.[1] 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 300h with a light flight-test instrumentation.[50]

The 737 MAX gained Federal Aviation Administration (FAA) certification on March 8, 2017.[11] It was approved by the EASA on March 27, 2017.[51] 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.[52] Boeing suspended 737 MAX flights on May 4,[12] and resumed flights on May 12.[53]

During the certification process, the FAA delegated many evaluations to Boeing, allowing the manufacturer to review their own product.[49][54] 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.[55]


The Boeing 737 MAX 8 entered service with Lion Air's subsidiary Malindo Air (wearing Batik Air Malaysia livery)

The first delivery was a MAX 8, handed over to Malindo Air (a subsidiary of Lion Air) on May 16, 2017; it entered service on May 22.[2] Norwegian Air subsidiary Norwegian Air International 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 US state of Connecticut, followed by a second rotation from Edinburgh to Stewart Airport, New York.[56]

Boeing aimed to match the 99.7% dispatch reliability of the 737 Next Generation (NG).[57] Southwest Airlines, the launch customer, took delivery of its first 737 MAX on August 29, 2017.[58] Boeing planned to deliver at least 50 to 75 aircraft in 2017, 10–15% of the more than 500 737s to be delivered in the year.[12]

After one year of service, 130 MAXs had been delivered to 28 customers, logging over 41,000 flights in 118,000 hours and flying over 6.5 million passengers. flydubai observed 15% more efficiency than the NG, more than the 14% promised, and dependability reached 99.4%. Long routes include 24 over 2,500 nmi (4,630 km), including a daily Aerolineas Argentinas service from Buenos Aires to Punta Cana over 3,252 nmi (6,023 km).[59]

In 2019, Moody's had estimated Boeing's operating margin to be $12–15 million for each 737 Max 8 at its list price of $121.6 million, 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 second crash, the FAA grounding and the severe disruption to production.[60][61] 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.[62][63][63][64] The rising costs also lead Moody’s to downgrade Boeing’s credit rating.[65]

Grounding and suspension of production

The Boeing 737 MAX was grounded worldwide in March 2019, after a malfunctioning flight control caused two new aircraft to crash in Ethiopia and Indonesia between November 2018 and March 2019, killing all 346 people onboard. During the groundings, Boeing redesigned the computer architecture that supported MCAS, while investigations faulted aircraft design and certification lapses. Boeing faces legal and financial consequences, as no deliveries of the MAX can be made while the aircraft is grounded, and airlines cancelled 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 is to check the remainder of the 400 undelivered planes.[66] Boeing had similar issues with 787s produced in South Carolina.[67] The FAA curtailed Boeing's delegated authority, and invited global aviation stakeholders to comment on pending changes to the aircraft and pilot training. The MAX is projected to return to service no earlier than October 2020.

From mid-April 2019, the company announced it was temporarily cutting production of the 737 aircraft from 52 per month to 42 amid the Boeing 737 MAX groundings.[68] Production of the LEAP-1B engine continued at an unchanged rate, enabling CFM to catch up its backlog within a few weeks.[69]

As the 737 MAX re-certification moved into 2020, Boeing suspended production from January to conserve cash and prioritize stored aircraft delivery.[70][16] The 737 MAX program was Boeing's largest source of profit.[71] Around 80% of the 737 production costs involve payments to parts suppliers, which may be as low as US$10 million per plane.[72] After the announcement, Moody’s cut Boeing’s debt ratings in December 2019, 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.[65] Moody's also warned the production halt would have wide and harmful impact to the whole aerospace and defense supply chain and, if and when production resumes, the ramp up would be slower than previously anticipated, as suppliers have to make adjustments to cost structures built for planned record output on the 737 program.[73]

CFM International reduced production of the 737 MAX's CFM LEAP-1B, in favor of the A320neo's LEAP-1A, but is prepared to meet demand for both aircraft.[74] Boeing has not said publicly how long the suspension will last. The last pre-suspension fuselages entered final assembly in early January 2020. Boeing, internally, may expect production to be halted for at least 60 days.[75] Industry observers began to question if Boeing's projection of record production rate of 57 per month would ever be reached.[76] In early January 2020, an issue was discovered in the software update, further delaying the return to service. The FAA is unlikely to approve the return until March. Several major U.S. airlines have extended cancellations of MAX flights until early June.[77]

In late January, production was expected to restart in April and take a year and a half to clear the inventory of 400 airplanes, ramp up slowly and build over time: Boeing might have delivered 180 stored jets by year-end and produce an equal number.[78] 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.[79] MAX supplier Spirit AeroSystems said it does not expect to return production rate to 52 per month until late 2022.[80] By early April, the COVID-19 pandemic led Boeing to shut down its other airliner production lines[81] and further delayed recertification of the MAX.[82] By late April 2020, Boeing signaled it hoped to win regulatory approval by August 2020.[83] On May 27, 2020, Boeing resumed 737 MAX production at a low production rate, as it will be ramped up according to customer deliveries, towards 31 monthly in 2021.[4]


In mid-2011, the objective was to match the A320neo's 15% fuel burn advantage. The initial reduction was 10–12%; it was later enhanced to 14.5%. The fan was widened from 61 in (150 cm) to 69.4 in (176 cm) by raising the nose gear and placing the engine higher and forward. The split winglet added 1–1.5%, a re-lofted tail cone 1% more. Electronically controlling the bleed air system improved efficiency. The new engine casings included chevrons similar to the 787 to help reduce engine noise.[84]

Aerodynamic changes

Boeing's new "split tip" winglet on the 737 MAX

The split tip wingtip device is designed to maximize lift while staying in the same ICAO Aerodrome Reference Code letter C gates as current 737s. It traces its design to the McDonnell Douglas MD-12 1990s twin-deck concept, proposed for similar gate restrictions before the Boeing merger.[85] A MAX 8 with 162 passengers on a 3,000 nmi (5,600 km) flight is to have up to a 1.8% better fuel burn than a blended-winglet-equipped aircraft and 1% over 500 nmi (930 km) at Mach 0.79.[85]

The new winglet is 9 ft 6 in (2.90 m) high.[38] Other improvements include a re-contoured tail cone, revised auxiliary power unit inlet and exhaust, aft-body vortex generators removal and other small aerodynamic improvements.[32] Aviation Partners offers a similar "Split-Tip Scimitar" winglet for previous 737NGs.[86] It resembles a three-way hybrid between a blended winglet, wingtip fence, and raked wingtip.

Structural and other changes

The 8 in (20 cm) taller nose-gear strut keeps the same 17-inch (43 cm) ground clearance of the engine nacelles.[32] New struts and nacelles for the heavier engines add bulk, the main landing gear and supporting structure are beefier, and fuselage skins are thicker in some places for a 6,500 lb (2,900 kg) increase to the MAX 8's empty aircraft weight.[32] To preserve fuel and payload capacity, its maximum takeoff weight is 7,000 lb (3,200 kg) heavier.[32]

Rockwell Collins will supply four 15.1-inch (380 mm) landscape liquid crystal displays (LCD), as used on the 787 Dreamliner, to improve pilots' situation awareness and efficiency.[87] 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".[88] Most of the systems are carried from the 737NG for a short differences-training course to upgrade flight crews.[32]

The 737 MAX extended spoilers are fly-by-wire controlled.[38] As production standard, the 737 MAX will feature the Boeing Sky Interior with overhead bins and LED lighting based on the Boeing 787's interior.[89]

The automatic stabilizer control system has been enhanced to include Maneuvering Characteristics Augmentation System (MCAS) in addition to Speed Trim System (STS). 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 compared to the previous versions of the 737 to the effect that automatic stabilizer trim control functions cannot be turned off while retaining electric trim switches functionality.[90]


LEAP mockup
Nacelle with chevrons for noise reduction

In 2011, the Leap-1B was initially 10–12% more efficient than the previous 156 cm (61 in) CFM56-7B of the 737NG.[27] 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.[32] The CFM56 bypass ranges from 5.1:1 to 5.5:1.[91] The two-shaft 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 driven by a two-stage turbine.[32] 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 849 lb (385 kg) more at 6,129 lb (2,780 kg).[32]

In August 2011, Boeing had to choose between 66 in (168 cm) or 68 in (173 cm) fan diameters necessitating landing gear changes to maintain a 17-inch (43 cm) 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 [but also] more weight and more drag", with more airframe changes.[92] The smaller Leap-1B engine will weigh less and have a lower frontal area but a lower bypass ratio leading to a higher thrust specific fuel consumption than the 78 in (200 cm) Leap-1A of the A320neo.[citation needed]

In November 2011, Boeing selected the larger fan diameter, necessitating a 6–8 in (150–200 mm) longer nose landing gear.[93][94] In May 2012, Boeing further enlarged the fan to 69.4 in (176 cm), paired with a smaller engine core within minor design changes before the mid-2013 final configuration.[95][96]

The nacelle features chevrons for noise reduction like the 787.[97] A new bleed air digital regulator will improve its reliability.[98] 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 engine nacelle lipskin is a GKN Aerospace one-piece, spun-formed aluminum sheet inspired by the 787.[38]

To mitigate the pitch-up tendency of the new flight geometry from the engines being located further forward and higher than previous engines, Boeing added the new Maneuvering Characteristics Augmentation System.[99]

Maneuvering Characteristics Augmentation System (MCAS)

Movable horizontal stabilizer on an Embraer ERJ-170

The Maneuvering Characteristics Augmentation System (MCAS) is a flight control law (software) first deployed on the Boeing KC-46 Air Force tanker, where it "moves the stabilizer in a wind-up turn".[100] MCAS adjusts the horizontal stabilizer trim to push the nose down when the aircraft is operating in manual flight, with flaps up, at an elevated angle of attack (AoA), so the pilot will not inadvertently pull the airplane up too steeply, potentially causing a stall. Contrary to descriptions in news reports, however, Boeing claims that MCAS is not an anti-stall system.

On the Boeing 737 MAX, MCAS was intended to mimic pitching behavior similar to aircraft in the previous generation of the series, the Boeing 737 NG. MCAS activated by input from only one of the airplane's two angle of attack sensors, making the system susceptible to a single point of failure. It could not be instinctively disabled by pulling on the control yoke. During aircraft certification, Boeing removed a description of MCAS in the MAX flight manuals, leaving pilots unaware of the system when the airplane entered service.[101]

On November 10, 2018, Boeing publicly revealed MCAS in a discussion with airline operators and other aviation interests twelve days after Lion Air Flight 610 crashed.[102] Yet, a recovery procedure highlighted by Boeing and the FAA failed to prevent the crash of Ethiopian Airlines Flight 302, which led to the global grounding of all 737 MAX aircraft pending investigations and software fixes.

In April 2019, Boeing admitted that MCAS played a role in both accidents. The investigations identified numerous defects with associated systems, including an AoA disagree message that should have prevented MCAS activation. The Wall Street Journal reported that Boeing failed to share information about that issue for "about a year" before the Lion Air crash in Indonesia.[103]


The 737-700, -800 and -900ER, the most widespread versions of the previous 737NG,[5] are succeeded by the 737 MAX 7, MAX 8 and MAX 9, respectively[104] (FAA type certificate: 737-7, -8, and -9[11]). The 737 MAX 8 entered service in May 2017,[2] and the MAX 9 entered service in March 2018.[105] The MAX 7 and MAX 200 (a higher density version of the MAX 8) were expected to enter service in 2019,[106][107] and the MAX 10 in 2020.[108]

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.[109]

737 MAX 7

737 MAX 7 at the 2018 Farnborough Airshow

Originally based on the 737-700, Boeing announced the redesign of the MAX 7 derived from the MAX 8 at the July 2016 Farnborough Air Show, accommodating two more seat rows than the 737-700 for 138 seats, up 12 seats.[110][111] 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 aft fuselage and a 30-inch longer forward fuselage; structural re-gauging and strengthening; and systems and interior modifications to accommodate the longer length.[112] It is to fly 1,000 nmi (1,900 km) farther than the -700 with 18% lower fuel costs per seat. Boeing predicts the MAX 7 to carry 12 more passengers 400 nmi (740 km) farther than A319neo with 7% lower operating costs per seat.[113] Boeing plans to improve its range from 3,850 nmi (4,430 mi; 7,130 km) to 3,915 nmi (4,505 mi; 7,251 km) after 2021.[114]

Production on the first 65-foot-long (20 m) wing spar for the 737-7 began in October 2017.[108] Assembly of the first flight-test aircraft began on November 22, 2017[115] and was rolled out of the factory on February 5, 2018.[116] The MAX 7 took off for its first flight on March 16, 2018, from the factory in Renton, Washington and flew for three hours over Washington state.[117] It reached 250 kn (460 km/h) and 25,000 ft (7,600 m), performed a low approach, systems checks and an inflight engine restart, and landed in Moses Lake, Washington, Boeing's flight test center.[118]

Entry into service with launch operator Southwest Airlines was expected in January 2019,[108] but the airline deferred these orders until 2023–2024.[119] WestJet also converted its order for MAX 7s, originally due for delivery in 2019, into MAX 8s and is not expected to take any MAX 7s until at least 2021.[120] Customers for the aircraft include Southwest Airlines (30), WestJet (23), Canada Jetlines (5) and ILFC Aviation (5).[5] The MAX 7 seems to have fewer than 100 orders among over 4,300 MAX total sales.[113]

737 MAX 8

A top view of the MAX 8 showing double overwing exits

The first variant developed in the 737 MAX series, the MAX 8 replaces the 737-800 with a longer fuselage than the MAX 7. Boeing plans to improve its range from 3,515 nmi (4,045 mi; 6,510 km) to 3,610 nmi (4,150 mi; 6,690 km) after 2021.[114] On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8.[121] 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 449 kn (832 km/h) and a weight of 140,500 lb (63,700 kg), at a lower than optimal altitude (FL350 vs. the preferred FL390) and with an "unusually far forward" center of gravity, the test aircraft consumed 4,460 lb (2,020 kg) of fuel per hour.[32]

The Boeing 737 MAX 8 completed its first flight testing in La Paz, Bolivia. The 13,300-foot altitude at El Alto International Airport tested the MAX's capability to take off and land at high altitudes.[122] Its first commercial flight was operated by Malindo Air on May 22, 2017, between Kuala Lumpur and Singapore as Flight OD803.[2] In early 2017, a new -8 was valued at $52.85 million, rising to below $54.5 million by mid 2018.[123]

In September 2014, Boeing launched a high-density version of the 737 MAX 8, the 737 MAX 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.[124][125] Three of eight galley trolleys are removed to accommodate more passenger space.[126] An order with Ryanair for 100 aircraft was finalized in December 2014.[127] The variant is officially designated 737-8200.[128]

In mid-November 2018, the first of the 135 ordered by Ryanair rolled out, in a 197-seat configuration.[129] It was first flown from Renton on January 13, 2019,[130] and was due to enter service in April 2019, with four further MAX 200s expected later in 2019,[131] though these deliveries were deferred while the MAX is grounded; Ryanair has stated that it intends to place a further order once flights resume.[132] 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, with "at best" 10 aircraft in service for the peak summer season.[133]

Airlines have been shown a 737-8ERX concept based on the 737 MAX 8 with a higher 194,700 lb (88.3 t) maximum take-off weight using wings, landing gear and central section from the MAX 9 to provide a longer range of 4,000 nautical miles (4,600 mi; 7,400 km) with seating for 150, closer to the Airbus A321LR.[134]

737 MAX 9

737 MAX 9 first flight on April 13, 2017

The 737 MAX 9 will replace the 737-900 and has a longer fuselage than the MAX 8. Boeing plans to improve its range from 3,510 nmi (4,040 mi; 6,500 km) to 3,605 nmi (4,149 mi; 6,676 km) after 2021.[114] Lion Air is the launch customer with an order for 201 in February 2012.[38] It made its roll-out on March 7, 2017, and first flight on April 13, 2017;[135] it took off from Renton Municipal Airport and landed at Boeing Field after a 2 hr 42 min flight.[136] It was presented at the 2017 Paris Air Show.[137]

Boeing 737-9 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.[50] It was certified by February 2018.[138] Asian low-cost carrier Lion Air Group took delivery of the first on March 21, 2018, before entering service with Thai Lion Air.[105] As the competing A321neo attracts more orders, the value of 737-9 is the same as a 2018 737-8 at $53 million.[139]

737 MAX 10

737 MAX 10 rendering

To compete with the Airbus A321neo, loyal customers such as Korean Air and United Airlines pressed Boeing to develop a larger variant than the MAX 9, of which Boeing revealed studies in early 2016.[140] As the A321neo had outsold the MAX 9 five-to-one, the proposed MAX 10 included a larger engine, stronger wing, and telescoping landing gear in mid-2016.[141] In September 2016, it was reported that the variant would be simpler and lower-risk with a modest stretch of 6–7 ft (1.83–2.13 m) for a length of 143–144 ft (43.6–43.9 m), seating 12–18 more passengers for 192-198 in a dual-class layout or 226-232 for a single class, needing an uprated 31,000 lbf (140 kN) CFM LEAP-1B that could be available by 2019, or 2020, and would likely require a landing-gear modification to move the rotation point slightly aft.[142]

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 3,100 nautical miles (3,600 mi; 5,700 km) range reduced from 3,300 nautical miles (3,800 mi; 6,100 km) of the -9.[140] In early 2017, Boeing showed a 66 in (1.7 m) stretch to 143 feet (44 m), 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 CFM Leap 1B engine from the MAX 9 with a trailing-link main landing gear as the only major change.[143] Boeing 737 MAX Vice President and General Manager Keith Leverkuhn says the design has to be frozen in 2018, for a 2020 introduction.[140]

Boeing hopes that 737-900 operators and 737 MAX 9 customers like United Airlines, Delta Air Lines, Alaska Airlines, Air Canada, Lion Air, and Chinese airlines will be interested in the new variant.[144] Boeing predicts a 5% lower trip cost and seat cost compared to the A321neo.[145] 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".[146] AerCap CEO Aengus Kelly is cautious and said the -9 and -10 "will cannibalize each other".[140]

MAX 10 model at ILA Berlin Air Show 2018

The MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers.[147][148] 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.[149] Boeing ended the 2017 Paris Air Show with 361 orders and commitments, including 214 conversions, from 16 customers,[150] including 50 orders from Lion Air.[151]

The variant configuration was firmed up by February 2018,[152] and by mid-2018, the critical design review was completed. As of August 2018, 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 a 9.5 inches (24 cm) taller gear. Driven by the existing retraction system, a shrink-link mechanical linkage mechanism at the top of the leg, inspired by carrier aircraft designs, allows the gear to be drawn in and shortened while being retracted into the existing wheel well.[153][154] Entry into service is slated for July 2020.[155]

On November 22, 2019, Boeing unveiled the first MAX 10 to employees in its Renton factory, Washington, scheduled for the first flight in 2020.[156] At the time, 531 Max 10s were on order, compared to 3,142 A321neos sold, capable of carrying 244 passengers or to fly up to 4,700 nmi (8,700 km) in its heaviest A321XLR variant.[157] The Max 10 has similar capacity as A321XLR, but shorter range and much poorer field performance in smaller airports than A321XLR.[158]

Boeing Business Jet

The BBJ MAX 8 and BBJ MAX 9 are proposed business jet variants of the Boeing 737 MAX 8 and 9 with new CFM LEAP-1B engines and advanced winglets providing 13% better fuel burn than the Boeing Business Jet; the BBJ MAX 8 will have a 6,325 nmi (11,710 km) range and the BBJ MAX 9 a 6,255 nmi (11,580 km) range.[159] The BBJ MAX 7 was unveiled in October 2016, with a 7,000 nmi (12,960 km) range and 10% lower operating costs than the original BBJ while being larger.[160] The MAX BBJ 8 first flew on April 16, 2018, before delivery later the same year, and will have a range of 6,640 nmi (12,300 km) with an auxiliary fuel tank.[161]

Replacement airliner

In November 2014, Boeing talked about developing a clean sheet aircraft to replace the 737. The airplane was to have a similar fuselage but made from composite materials developed for the Dreamliner.[162] Boeing also considered a parallel development along with the 757 replacement, similar to the development of the 757 and 767 in the 1970s.[163]

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.[164][165] By December 2011, the 737 MAX had 948 commitments and firm orders from thirteen customers.[166] On September 8, 2014, Ryanair agreed to 100 firm orders with 100 options.[167] In January 2017, aircraft leasing company GECAS ordered 75.[168] By January 2019 the 737 MAX had 5,011 firm orders from 78 identified customers,[5] with the top three being Southwest Airlines with 280, flydubai with 251, and Lion Air with 251.[5] The first 737 MAX 8 was delivered to Malindo Air on May 16, 2017.[12]

Following the groundings in March 2019, Boeing suspended all deliveries of 737 MAX aircraft,[169] reduced production from 52 to 42 aircraft per month,[68] and on December 16, 2019, announced that production would be suspended from January 2020 to conserve cash and prioritize delivery of the 387 aircraft in storage once recertified.[70] At the time of the grounding, the 737 MAX had 4,636 unfilled orders[170] valued at an estimated $600 billion[171] but had a net negative 183 orders in 2019 from cancellations.[172] By May 31, 2020, orders had declined to 4,283.[5]

Boeing 737 MAX orders and deliveries
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 Total
Orders 150 908 668 861 409 530 759 720 −93 −353 4559
Deliveries 74 256 57 0 387

As of June 30, 2020[173]

Cumulative Boeing 737 MAX orders and deliveries



As of June 30, 2020[173]

Accidents and incidents

Grounded 737 MAX aircraft at Boeing Field in Seattle

The global fleet of nearly 400 737 MAXs flew 500,000 flights from March 2017 to March 2019, and experienced two fatal accidents for an accident rate of four per million flights when it was grounded. The previous generations of the Boeing 737 averaged 0.2 accidents per million flights.[174]

Lion Air Flight 610

On October 29, 2018, Lion Air Flight 610, 737 MAX 8 registration PK-LQP, plunged into the Java Sea 13 minutes after takeoff from Soekarno–Hatta International Airport, Jakarta, Indonesia. The flight was a scheduled domestic flight to Depati Amir Airport, Pangkal Pinang, Indonesia. All 189 people on board died. This was the first fatal aviation accident and first hull loss of a 737 MAX. The aircraft had been delivered to Lion Air two months earlier.[175][176] 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 Maneuvering Characteristics Augmentation System (MCAS) flight-control system.[177] Indonesia's Komite Nasional Keselamatan Transportasi released its final report into the accident on October 25, 2019,[178] attributing the crash to the MCAS pushing the aircraft into a dive 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.[179]

Ethiopian Airlines Flight 302

On March 10, 2019, Ethiopian Airlines Flight 302, 737 MAX 8 registration ET-AVJ, crashed approximately six minutes after takeoff from Addis Ababa, Ethiopia,[180] on a scheduled flight to Nairobi, Kenya,[181] killing all 149 passengers and 8 crew members on board. The aircraft was four months old at the time.[182] The cause of the crash was initially unclear, though the aircraft's vertical speed after takeoff was reported to be unstable.[183] 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.[184] On April 4, Ethiopian transport minister Dagmawit Moges stated that the crew "performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft".[185]

The subsequent findings in the Ethiopian Airlines crash and the Lion Air crash led to the Boeing 737 MAX groundings across the world. On August 19, 2019, Forbes estimated that the 737 MAX would not resume service before 2020.[186]


737 MAX Characteristics [187]
Variant 737 MAX 7 737 MAX 8 / MAX 200 737 MAX 9 737 MAX 10
Seating 153 (8J + 145Y) to 172 max 178 (12J + 166Y) to 200 max 193 (16J + 177Y) to 220 max 204 (16J + 188Y) to 230 max
Seat pitch 28–29 in (71–74 cm) in high density, 29–30 in (74–76 cm) in economy, 36 in (91 cm) in business
Cargo capacity 1,139 cu.ft / 32.3 m3 1,540 cu.ft / 43.6 m3 1,811 cu.ft / 51.3 m3 1,961 cu.ft / 55.5 m3
Length 116 ft 8 in / 35.56 m 129 ft 6 in / 39.47 m 138 ft 4 in / 42.16 m 143 ft 8 in / 43.8 m
Wing 117 ft 10 in / 35.92 m span, 1,370 sq ft (127 m2) area[11]
Overall height[188] 40 ft 4 in / 12.3 m
MTOW 177,000 lb / 80,286 kg 181,200 lb / 82,191 kg 194,700 lb / 88,314 kg 197,900 lb / 89,765 kg
Maximum Payload 46,040 lb / 20,882 kg
OEW[189] 99,360 lb / 45,070 kg
Fuel capacity 6,820 USgal / 25,816 L – 45,694 lb / 20,730 kg (no ACT)[b]
Engine (× 2) CFM International LEAP-1B, 69.4 in (176 cm) Fan diameter,[190] 26,786–29,317 lbf (119–130 kN)[11]
Cruising speed Mach 0.79 (453 kn; 839 km/h)[191]
Range[192] 3,850 nmi / 7,130 km 3,550 nmi / 6,570 km[c] 3,550 nmi / 6,570 km[d] 3,300 nmi / 6,110 km[d]
Ceiling 41,000 ft (12,000 m)[11]
Takeoff (ISA, SL, MTOW) 7,000 ft (2,100 m) 8,300 ft (2,500 m) 8,500 ft (2,600 m)
Landing (SL, MLW, dry) 5,000 ft (1,500 m) 5,000 ft (1,500 m) 5,500 ft (1,700 m)
ICAO Type[194] B37M B38M B39M B3XM

See also

Related development

Aircraft of comparable role, configuration and era