The Boeing 737 MAX is an American narrow-body aircraft series designed and produced by Boeing Commercial Airplanes as the fourth generation of the Boeing 737, succeeding the Boeing 737 Next Generation (NG).
Boeing 737 MAX
A WestJet Boeing 737 MAX 8 on final approach
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 In service
Primary users Southwest Airlines
Air Canada
American Airlines
Lion Air
Produced 2014–present[3]
Number built 219 as of September 2018[4]
Program cost Airframe only: $1–1.8 billion; including engine development: $2–3B[5]
Unit cost
MAX 7: US$96.0 million
MAX 8: $117.1M
MAX 200: $120.2M
MAX 9: $124.1M
MAX 10: $129.9M as of 2018[6]
Developed from Boeing 737 Next Generation
The program was launched on August 30, 2011.[7] The first flight was on January 29, 2016.[1] It gained FAA certification on March 8, 2017.[8] The first delivery was a MAX -8 on May 6, 2017 to Malindo Air,[9]which put it into service on May 22, 2017.[2] The 737 MAX is based on earlier 737 designs. The MAX is re-engined with more efficient CFM International LEAP-1B powerplants, aerodynamic improvements (most notably split-tip winglets), and airframe modifications.
The 737 MAX series is offered in four lengths, typically offering 138 to 230 seats and a 3,215 to 3,825 nmi (5,954 to 7,084 km) range. The 737 MAX 7, MAX 8, and MAX 9 replace, respectively, the 737-700, -800, and -900. Additional length is offered with the further stretched 737 MAX 10. As of September 2018, the Boeing 737 MAX has received 4,783 firm orders.[10]
Contents
DevelopmentEdit
BackgroundEdit
In 2006, Boeing started considering the replacement of the 737 with a "clean-sheet" design that could follow the Boeing 787 Dreamliner.[11] In June 2010, a decision on this replacement was postponed into 2011.[12]
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.[13] In February 2011, Boeing’s CEO Jim McNerney maintained "We're going to do a new airplane."[14] At the March 2011 ISTAT conference, BCA President James Albaugh was not sure about a 737 re-engine, like Boeing CFO James A. Bell stated at JP Morgan Aviation, Transportation and Defence conference the same month.[15] 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.[16]
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.[17] The order broke Boeing's monopoly with the airline and forced Boeing into a re-engined 737.[18] As this sale included a Most-Favoured-Customer Clause, the European airframer has to refund any difference to American if it sells to another airline at a lower price, so Airbus can not give a competitive price to competitor United Airlines, leaving it to a Boeing-skewed fleet.[19]
Program launchEdit
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 16% lower fuel burn than the Airbus A320ceo and 4% lower than the A320neo.[7] Studies for additional drag reduction were performed during 2011, including revised tail cone, natural laminar flow nacelle, and hybrid laminar flow vertical stabilizer.[20] Boeing abandoned the development of a new design.[21] Boeing expects the 737 MAX to meet or exceed the range of the Airbus A320neo.[22] Firm configuration for the 737 MAX was scheduled for 2013.[23]
In March 2010, the estimated cost to re-engine the 737 by Mike Bair, Boeing Commercial Airplanes' vice president of business strategy & marketing, would be $2–3 billion including the CFM engine development and during Boeing 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 ($1–1.8 billion)—while Bernstein Researchon 23 January 2012 concluded this will be twice that of the Airbus A320neo.[5]
Fuel consumption is reduced by 14% from the 737NG.[24] 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.[25]
ProductionEdit
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Boeing 737 MAX roll-out in December 2015 with the first 737 MAX 8
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.[26] On December 8, 2015, the first 737 MAX–a MAX-8 named "Spirit of Renton"–was rolled out at the Boeing Renton Factory.[27][28]
Because GKN could not produce the titanium honeycombinner 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 70 percent of the 737 airframe, including the fuselage, thrust reverser, engine pylons, nacelles, and wing leading edges.[29]
A new spar-assembly line with robotic drilling machines should increase throughput by 33 percent. The Electroimpact automated panel assembly line sped up the wing lower-skin assembly by 35 percent.[30] Boeing plans to increase its 737 MAX monthly production rate from 42 planes in 2017 to 57 planes by 2019.[31]
The rate increase strains 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.[32] 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.[33]
Flight testingEdit
The first flight took place on January 29, 2016, nearly 49 years after the maiden flight of the 737, a 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.[34]
The 737 MAX gained FAA certification on March 8, 2017.[8] It was approved by the EASA on March 27, 2017.[35] 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.[36] Boeing suspended the 737 MAX flights on May 4,[9] and resumed flights on May 12.[37]
IntroductionEdit
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 Hartford International Airport in the US state of Connecticut, followed by a second rotation from Edinburgh to Stewart Airport, New York.[38]
Boeing aims to match the 99.7% dispatch reliability of the NG.[39] Southwest Airlines, the launch customer, took delivery of its first 737 MAX on August 29, 2017.[40] Boeing plans to deliver at least 50 to 75 aircraft in 2017, 10-15% of the more than 500 737s to be delivered in the year.[9]
After one year of service, 130 have 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 Argentinasservice from Buenos Aires to Punta Cana over 3,252 nmi (6,023 km).[41]
DesignEdit
In summer of 2011, the objective was to match the A320neo 15% fuel burn advantage, but the initial reduction was 10–12%; it was later enhanced to 14.5%: the fan was widened from 61 inches to 69.4 inches by raising the nose gear and placing the engine higher and forward, the split winglet added 1–1.5%, a relofted tail cone 1% more and electronically controlling the bleed air system improves efficiency.[42]
EnginesEdit
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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.[43] 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.[24]The CFM56 bypass ranges from 5.1:1 to 5.5:1.[44] 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.[24]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).[24]
In August 2011, Boeing had to choose between 66 in (168 cm) or 68 in (173 cm) fan diameters necessitating few landing gear changes to maintain a 17 in (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.[45] 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 (15–20 cm) longer nose landing gear.[46][47] 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.[48]
The nacelle features chevrons for noise reduction like the 787.[49] A new bleed air digital regulator will improve its reliability.[50] 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.[30]
Aerodynamic improvementsEdit
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.[51] It should deliver at least 1.5% improvements in fuel economy or even more if the proposed laminar flow surface treatment meets expectations. A MAX 8 with 162 passengers on a 3,000 nmi (5,600 km) mission will have up to a 1.8% better fuel burn than a blended-winglet-equipped aircraft and even 1% over 500 nmi (930 km) at Mach 0.79.[51]
The new winglet is 9 ft 6 in (2.90 m) high.[30] 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.[24] Aviation Partnersoffers a similar "Split-Tip Scimitar" winglet for previous 737NGs.[52] It resembles a three-way hybrid between a blended winglet, wingtip fence, and raked wingtip.
Structural changes and other improvementsEdit
The 8 in (20 cm) taller nose-gear strut keeps the same 17 in (43 cm) ground clearance of the engine nacelles.[24] 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.[24] To preserve fuel and payload capacity, its maximum takeoff weight is 7,000 lb (3,200 kg) heavier.[24]
Rockwell Collins will supply four 15.1-inch (380 mm) landscape liquid crystal displays (LCD), as used on the 787 Dreamliner, to improve pilots' situational awareness and efficiency.[53]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".[54] Most of the systems are carried from the 737NG for a short differences-training course to upgrade flight crews.[24]
The 737 MAX extended spoilers are fly-by-wire controlled.[30] 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.[55]
VariantsEdit
The 737-700, -800 and -900ER, the most widespread versions of the previous 737NG,[10]are replaced by the 737 MAX 7, MAX 8 and MAX 9, respectively[56] (FAA type certificate: 737-7, -8, and -9[8]). The 737 MAX 8 entered service in May 2017,[2] and the MAX 9 entered service in March 2018.[57] The MAX 7 is expected to enter service in January 2019, followed by the MAX 200 later in 2019, and the MAX 10 in 2020.[58]
Boeing forecasts that 60–65% of demand for the airliner will be for the 737 MAX 8 variant, 20–25% for the MAX 9 and MAX 10, and 10% for the MAX 7.[59]
737 MAX 7Edit
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737 MAX 7 at 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.[60][61] The redesign uses the 737-8 wing and landing gear; a pair of overwing 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.[62] 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.[63] 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.[64]
Production on the first 65 ft (19.8 m) long wing spar for the 737-7 began in October 2017.[58]Assembly of the first flight-test aircraft began on November 22, 2017[65] and was rolled out of the factory on February 5, 2018.[66] 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.[67] 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.[68]
Entry into service with launch operator Southwest Airlines is expected in January 2019.[58]Entry into service with WestJet will follow shortly, with 5 deliveries expected in 2019.[69]Customers for the aircraft include Southwest Airlines (30), WestJet (23), Canada Jetlines (5) and ILFC Aviation (5).[10] The -7 seems to have fewer than 100 orders among over 4,300 MAX sales.[63]
737 MAX 8Edit
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A top view of the MAX 8 showing double overwing exits
The first variant developed in the 737 MAX series, the MAX 8 will replace 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.[64] On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8.[70]The MAX 8 has a lighter empty weight and higher maximum takeoff weight than the A320neo and in cruise at 140,500 lb (63,700 kg), it burns 4,460 lb (2,020 kg) per hour at Mach 0.78 (450 kn; 833 km/h) and FL350, at a suboptimal flight level and forward center of mass.[24]
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.[71]
737 MAX 200Edit
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 exit door is required because of the higher passenger capacity. Boeing states that this version will be 20% more cost efficient per seat than current 737 models, and will be the most efficient narrow-body on the market when delivered, including 5% lower operating costs than the 737 MAX 8.[72][73] Three of eight galley trolleys are removed to accommodate more passenger space.[74] A 100 aircraft order with Ryanair was completed on December 1, 2014.[75] It is to enter service in the second quarter of 2019.[76]
Proposed 737-8 ERXEdit
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.[77]
737 MAX 9Edit
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737 MAX 9 first flight
The 737 MAX 9 will replace the 737-900 with 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.[64] Lion Air is the launch customer with an order for 201 in February 2012.[30] It made its roll-out on March 7 and first flight on April 13, 2017;[78] it took off from Renton Municipal Airport and landed at Boeing Field after a 2 hr 42 min flight.[79] It was presented at the 2017 Paris Air Show.[80]
Boeing 737-9 flight tests were scheduled to run through 2017, with 30% of the -8 tests repeated; aircraft 1D001 was used for autoland, avionics, flutter, and mostly stability-and-control trials, while 1D002 was used for environment control system testing.[34] It was certified by February 2018.[81] Asian low-cost carrier Lion Air Group took delivery of the first on March 21, 2018 before entering service with Thai Lion Air.[57]
737 MAX 10Edit
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 which Boeing revealed studies of in early 2016.[82] 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.[83] 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 dual class or 226-232 in 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 simple landing gear modification to move the rotation point slightly aft.[84]
In October 2016, Boeing's board 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.[82] 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.[85] Boeing 737 MAX Vice President and General Manager Keith Leverkuhn says the design has to be frozen in 2018 for a 2020 introduction.[82]
Boeing prospects 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.[86] Boeing predicts a 5% lower trip cost and seat cost compared to the A321neo.[87] 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".[88] AerCap CEO Aengus Kelly is cautious and said the -9 and -10 "will cannibalize each other".[82]
As it progressed towards a telescopic semi-levered main landing gear design like the 777 and 787-10, Boeing anticipated a launch at the June 2017 Paris Airshow for a total market of 1,000 airplanes.[89] Lion Air is a possible launch customer at this Air Show with United Airlines, Norwegian or Spicejet are cited as interested, but commitments could be conversions of existing orders rather than new sales.[90] Ryanair is expected to hold out for the best possible price before placing an order.[91]
The MAX 10 was launched on June 19, 2017 with 240 orders and commitments from more than 10 customers.[92][93] 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.[94] Boeing ended the 2017 Paris Air Show with 361 orders and commitments, including 214 conversions, from 16 customers,[95] including 50 orders from Lion air.[96]
Its configuration was firmed up by February 2018.[97] Its modified landing gear will require additional flight-testing.[34] To fit the 9 in (23 cm) taller main landing gear in the same wheel well, at the lower end the semi-levered gear includes an additional shock absorber strut to keep the wheels on the ground as the aircraft rotates and move the pivot point aft, and at the upper end a shrinking, translating mechanical linkage enables it to be drawn in and shortened while being retracted, inspired from carrier aircraft designs. It weighs 5,500 lb (2,500 kg) less than the A321neo, which needs 7,000 lb (3,200 kg) more takeoff weight and 5,000 lb (2,300 kg) more thrust to fly the same mission.[98]
By Summer 2018, the variant critical design review was done as it passed 70% of the detailed design. Assembly was underway for a first flight targeted for late 2019 and entry into service for 2020. The landing gear design was disclosed: a telescoping oleo-pneumatic strut with a down-swinging lever permit a 9.5 in. (24 cm) taller gear. Driven by the existing retraction system, a shrink link mechanism at the top of the leg allow to keep the existing wheel well to preserve development costs.[99]
Boeing Business JetEdit
The BBJ MAX 8 and BBJ MAX 9 are proposed business jets 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.[100] The BBJ MAX 7 was unveiled in October 2016 with a 7,000 nautical miles (12,960 km) range and 10% lower operating costs than the original BBJ while being larger.[101] The MAX BBJ 8 first flew on April 16, 2018, before delivery later the same year, and will reach 6,640 nmi (12,300 km) with an auxiliary fuel tank.[102]
Orders and deliveriesEdit
Initially, the customers for the 737 MAX were not disclosed, except for American Airlines. On November 17, 2011, Boeing released the names of two other customers – Lion Air and SMBC Aviation Capital. At that time, Boeing reported 700 commitments from 9 customers for the 737 MAX.[103][104] On December 13, 2011, Southwest Airlines ordered 150 737 MAX aircraft with 150 options.[105]
By December 2011, Boeing had 948 commitments and firm orders from 13 customers for the 737 MAX.[106] On September 8, 2014, Ryanair signed an agreement with Boeing to purchase up to 200 new Boeing 737 MAX 200 "gamechanger" aircraft - comprising 100 firm orders and 100 options.[107] In January 2017, aircraft leasing company GECAS ordered 75 more 737 MAX 8 airliners.[108]
As of September 2018, Boeing had 4,783 firm orders from 98 identified customers for the 737 MAX.[4] The top three identified airline customers for the 737 MAX are Southwest Airlines with 280 orders, flydubai with 251 orders, and Lion Air with 251 orders.[10] The first new series aircraft, a MAX 8, was delivered to Malindo Air on May 16, 2017.[9]
Boeing 737 MAX orders and deliveries
9.25% 
19.06% 
