Boeing 737.

SPECS

ASSEMBLY

INTERIOR

HISTORY

ORDERS

The Boeing 737 concept was first mooted in 1964 and was to be a low-cost solution derived from the Boeing 727 and Boeing 707, with the first aircraft being produced in 1967.  The original 737-100 was short and stocky, but over the following forty-odd years, eight more variants have been produced. Seating capacity has grown from 85 to 215 passengers.

The production has been so prolific that as of December 2022, 11,112 aircraft have been produced with the order book standing at around 7,000 aircraft still to be delivered. On average there are 1,250 Boeing 737s airborne at any given time with 2 landing or departing every 5 seconds.

The twelve variants of the Boeing 737 are split into four generations of aircraft as follows:

  • Original Generation - Boeing 737-100 and Boeing 737-200.

  • Classic Generation - Boeing 737-300, 737-400, and Boeing 737-500.

  • Next Generation(NG) - Boeing 737-600, 737-700, 737-800, and Boeing 737 900ER.

  • MAX Generation - 737 MAX 7, MAX 8, and MAX 9.

A Boeing 737-219 of NAC (National Airways Corporation of New Zealand) in landing configuration.

A Boeing 737-219 of NAC (National Airways Corporation of New Zealand) in landing configuration. Notice the long jet engine pipe that protrudes fore and aft of the wing, as well as the trail of smoke left behind.

Being the only narrow-body aircraft now being produced by Boeing, the 737 has replaced the Boeing 707, 727, and 757 as well as the DC9, MD80 and MD90. The main competition for the Boeing 737 today is the Airbus A320 family of aircraft. On its launch, it has to compete with the BAC 1-11, Fokker F28 and the DC9. One of the 737s' advantages over these rivals was its wider cabin allowing for a 6 abreast seating layout as compared to 5 abreast offed by its rivals.

The Boeing 737 100 and Boeing 737 200 variants were powered by Pratt and Whitney JT8D-1 engines which were wing-mounted. These engines were low bypass engines and were distinctive in the way they sat under the wing-like a long pipe extending forward and aft of the wing. The reverse thrust was provided by half-shells that extended back over the exhaust tailpipe and redirected air forward over and under the wing.

South African Airlink Boeing 737-244 Reg ZS-SIM

South African Airlink Boeing 737-244 Reg ZS-SIM.

The Boeing 737 300 was the first major rethink of the aircraft design with a longer fuselage, greater wingspan, and new engines. The CFM56-3B-1 high-bypass turbofan was chosen, and to solve the problem of low ground clearance the engine was placed forward of the wing on a wing-mounted pylon. In addition, engine accessories were placed on the sides rather than under the engine which made the nacelles slightly triangular rather than circular when viewed from the front.

The Next Generation family of variants delivered various improvements in technology: More efficient engines, improved aerodynamics, increased passenger capacity, longer range, and electronic cockpits to name but a few.

With the Boeing 787 Dreamliner now in production, Boeing, in 2011, turned their attention back to the Boeing 737. It was time to update this popular model once more to bring it into line with the new modern concepts, designs, and materials used in Boeing 787 Dreamliner. Plans were announced in July 2011 for the Boeing 737 MAX which will be powered by CFM International Leap-1B engines. American Airlines intends to order 100 of the new variant.

flydubai Boeing 737-800 Reg A6-FDV

flydubai Boeing 737-800 Registration A6-FDV.

The first 271 Boeing 737 aircraft were manufactured next to Boeing Field which is now officially known as King County International Airport. The Renton factory at this time was still in full-on production of the Boeing 707 and Boeing 727 aircraft. Production of the Boeing 737 was moved to Renton in late 1970.

Spirit Aerosystems of Wichita, Kansas, who bought some of Boeings' Witchita assets, manufacture a significant part of the fuselage today. The completed fuselages are then transported by train to Renton.

At the Renton plant the wings, fuselage, and landing gear are married together, as well as avionics and interiors being installed as it moves down the assembly line.

The aircraft is jacked up so that the deployment and retraction of the landing gear can be tested. Also, a test called the "high blow" is performed where the interior of the fuselage is pumped full of air to the equivalent pressure differential of 93,000 feet of altitude. This enables the testing for leaks.

ASSEMBLY

Boeing 737 fuselages in the Witchita assembly plant.

Boeing 737 fuselages in the Spirit Aerosystems Witchita assembly plant.

In December 2005 a second assembly line was added to increase the production output. This enabled the production of 31 aircraft per month. The current time to assemble an aircraft is eleven days with a future target of just six days. A third production line is being proposed to address the waiting time of three years for a new Boeing 737, a backlog in excess of 1,600 aircraft.

The completed aircraft is then tested fully before undertaking its maiden flight. The culmination of the maiden flight is at Boeing Field where the aircraft is painted in the customer livery, as well as other customised fit-out requirements. Depending on the customer livery, it takes around 200 litres of paint to cover a 737, some 130 Kilograms in weight. Full tests and fine-tuning take place before the aircraft is ready for delivery to the customer.

Boeing 737-800 fuselages being transported from Witchita to the final assembly plant.

Boeing 737-800 fuselages are being transported from Witchita to the final assembly plant.

As is the case with many modern aircraft, the manufacturing of the various components, some 367,000 for a 737NG, are outsourced to companies all around the world. Some of the main components are supplied as follows:

ComponentManufacturer
Fuselage, engine nacelles and pylonSpirit AeroSystems, Witchita (previously Boeing)
Slats and flapsSpirit AeroSystems, Tulsa (previously Boeing)
WingsBoeing, Renton, Washington
DoorsVought, Stuart, Florida
SpoilersGoodrich, Charlotte, North Carolina
Tail FinXi'an Aircraft Industry, China
Horizontal StabiliserKorea Aerospace Industries, South Korea
AileronsAsian Composites Manufacturing, Malaysia
RudderBombardier, Belfast, Northern Ireland
Tail SectionAlcoa / Shanghai Aircraft Manufacturing, China
Main Landing Gear DoorsAerospace Industrial Development Corp, Taiwan
Inboard FlapsMitsubishi, Japan
ElevatorFuji, Japan
WingletsKawasaki, Japan
Forward Entry DoorChengdu Aircraft, China
Over-wing ExitsChengdu Aircraft, China
Wing To Body FairingsBHA Aero Composite Parts Co. Ltd, China
Tail ConeBHA Aero Composite Parts Co. Ltd, China
The Boeing 737 assembly line at Renton.

The Boeing 737 assembly line at Renton.

Turkish Airlines 737 seats.

A Turkish Airlines Boeing 737 is ready to have seats installed. Note the rudder is already painted. These are painted prior to being attached as they need to be very finely balanced.

SPECIFICATIONS

In the more than fifty years of its existence, the Boeing 737 has evolved from a stumpy little twin-jet airliner into a family of high-performance and versatile jet transports. Check out the Boeing 737 Specs tables below to get a clear picture of how these city jets stack up.

The global climate of rising fuel costs, as well as increased competition in the form of the Airbus A320, have ensured that Boeing continues to bring out more improved versions of the type.

Boeing737 MAX 9 N7379E

This Boeing 737 MAX 9 with apt registration of N7379E was a test bed aircraft which was then delivered to Thai Lion Air with registration HS-LSJ.

Boeing 737 Specs Tables

FamilyVariant
Original737 100737 200ADV---
Classic737-300737-400737-500--
Next Generation (NG)737-600737-700737-800737-900-
MAXMAX-7MAX-9MAX-200MAX-9MAX-10

In its fifty plus years the Boeing 737 has gone through many changes to keep pace with improvements in technology and changes in economic times. There have been fourteen variants in four families which are shown below.

An Alaska Airlines Boeing 737-800 in flight.

An Alaska Airlines Boeing 737-800 registration N546AS in flight.

FAMILYORIGINALCLASSIC
Variant737 100737 200ADV737 300737 400737 500
Flight Crew22
Milestones
Maiden Flight09 APR 196708 AUG 196724 FEB 198419 FEB 198830 JUN 1989
Launch Delivery28 DEC 196729 DEC 196728 NOV 198415 SEP 198828 FEB 1990
Launch AirlineLufthansaUnited AirlinesUS AirPiedmontSouthwest Airlines
Final Delivery02 NOV 196902 AUG 198817 DEC 199925 FEB 200021 JUL 1999
Power Plant
ModelJT8DCFM56-3
Type715AB2C-1B1
Thrust64.4Kn 14,000lb71.2Kn 16,000lb88.9Kn 20,000lb104.5Kn 23,500lb82.3Kn 18,500lb
Dimensions
Fuselage
Aircraft Length28.65M 94Ft30.53M 100Ft 2In33.40M 109Ft 7In36.45M 119Ft 7In31.01M 101Ft 9In
Fuselage Height4.01M (13Ft 2In)4.01M (13Ft 2In)
Fuselage Width (Outside)3.76M (12Ft 4In)3.76M (12Ft 4In)
Cabin Width3.54M (11Ft 5In)3.54M (11Ft 5In)
Cargo18M3 650Ft324.8M3 875Ft330.2M3 1,068Ft338.9M3 1,373Ft323.3M3 882Ft3
Wing
Span28.35M (93Ft)28.88M (94Ft 9In)
Wing Area102M2(1,098Ft2)105.4M2(1,134Ft 6In2)
Dihedral6 Degrees6 Degrees
Sweep Back25 Degrees25 Degrees
FAMILYORIGINALCLASSIC
Variant737 100737 200ADV737 300737 400737 500
Tail Fin
Aircraft Height11.28M (37Ft)11.12M (36Ft 6In)
Tail Fin Height6.15M (20Ft 2In)6.15M (20Ft 2In)
Tail Fin Area20.81M2 (224Ft2)23.13M2 (249Ft2)
Rudder Area5.22M2 (56Ft 2In2)5.22M2 (56Ft 2In2)
Sweep Back35 Degrees35 Degrees
Under carriage
Track5.23M 17Ft 2In5.25M 17Ft 3In
Wheelbase10.46M (34Ft 4In)11.38M (37Ft 4In)12.40M (40Ft 8In)14.27M (46Ft 10In)11.07M (36Ft 4In)
Number of Nose wheels22
Number of Main wheels44
Cabin
Max. Certified Seating124136149188140
Typical Seating113119149179140
Seats Abreast6 3x36 3x3
Weights
Max. Ramp Weight44,361K (97,816lb)52,615K (116,016lb)56,700K (125,023lb)63,049K (139,023lb)63,049K (139,023lb)
Max. Takeoff Weight44,225K (97,516lb)52,390K (115,520lb)56,472K (124,521lb)62,822K (138,522lb)62,823K (138,525lb)
Maximum Landing Weight40,687K (89,715lb)46,720K (103,018lb)51,710K (114,021lb)54,885K (121,021lb)49,895K (110,018lb)
Max. Zero Fuel38,555K (85,014lb)43,091K (94,857lb)47,625K (105,013lb)51,256K (113,019lb)46,720K (103,018lb)
Fuel
Fuel Capacity17,865L (4,720UG)19,532L (5,160UG)20,105L (5,312UG)20,105L (5,312UG)20,105L (5,312UG)
Speeds
Vmo/Mmo Velocity/Mach Maximum Operating speed350Kn 0.84M340Kn 0.82M
Cruise Speed IAS/Mach0.73M250/0.745
True Airspeed (Kt)420430
Ceiling (Ft)35,00037,00037,000
Range with Max Payload(nm)1,720Nm (3,185Km)2,645Nm (4,899Km)2,950Nm (5,463Km)2,800Nm (5,186Km)2,950Nm (5,463Km)
FAMILYORIGINALCLASSIC
Variant737 100737 200ADV737 300737 400737 500
FAMILYNEXT GENERATION (NG)737 MAX
Variant600700800900Max 7Max 8Max 200Max 9Max 10
Milestones
Prices (Millions)-US$89.1US$106.1US$112.6US$99.7US$121.6US$124.8US$128.9US$134.9
Maiden Flight22 JAN 199809 FEB 199731 JUL 199703 AUG 200016 MAR 201829 JAN 201613 JAN 201913 APR 2017Late 2019
Launch Delivery18 Sep 199817 Dec 199722 Apr 199815 May 2001201922 MAY 2017201921 March 20182020
Launch AirlineSASSouthwest AirlinesHapag LloydAlaska AirlinesWestjetMalindo AirRyan AirLion AirUnited Airlines
Power Plant
ModelCFM56-7CFM
Type7B187B207B247B26Leap-1B
Thrust82.0Kn, 18,500lb89.0Kn, 20,600lb107.0Kn, 24,200lb117.3Kn, 26,300lb119–130Kn, 26,786–29,317lb
Dimensions
Fuselage
Fuselage Length31.20M (102Ft 4In)33.60M (110Ft 3In)39.50M (129Ft 7In)42.10M (138Ft 2In)35.56M (116Ft 8In)39.52M (129Ft 8In)39.52M (129Ft 8In)42.16M (138Ft 4In)43.80M (143Ft 8In)
Fuselage Height4.01M, (12Ft 2In)4.01M, (12Ft 2In)
Fuselage Width (Outside)3.76M, (12Ft 4In)3.76M, (12Ft 4In)
Cabin Width3.53M,(11Ft 7In)3.53M,(11Ft 7In)
Wing
Span34.32M (112Ft 7In)35.92M (117Ft 10In)
Wing Area124.58M2 (1,340Ft2)127M2 (1,370Ft2)
Dihedral6 Degrees6 Degrees
Sweep Back25.02 Degrees25.03 Degrees
Tail Fin
Aircraft Height12.6M (41Ft 4In)12.3M (40ft 4in)
Tail Fin Height7.16M (23F 6In)7.16M (23F 6In)
Tail Fin Area26.44M2 (285Ft2)26.44M2 (285Ft2)
Rudder Area5.22M2 (56Ft2)5.22M2 (56Ft2)
FAMILYNEXT GENERATION (NG)737 MAX
Variant600700800900Max 7Max 8Max 200Max 9Max 10
Under carriage
Track5.76M (18Ft 11In)5.72M (18Ft 9In)
Wheelbase-12.6M (41Ft 4In)15.6M (51Ft 2In)-12.6M (41Ft 4In)15.6M (51Ft 2In)17.17M (56Ft 4In)-
Number of Nose wheels22
Number of Main wheels44
Cabin
Max. Certified Seating149189215149189200220244
Typical Seating145180140175192216
Seats Abreast66
Weights
Max. Ramp Weight65,317Kg (143,999lb)70,307Kg (155,000lb)79,229Kg (174,670lb)79,229Kg (174,670lb)-82,417Kg (181,729lb)---
Max. Takeoff Weight65,090Kg (153,499lb)70,080Kg (154.500lb)79,002Kg (174,170lb)79,002Kg (174,170lb)80,286Kg (177,000lb)82,190Kg (181,229lb)82,191Kg (181,200lb)88,314Kg (194,700lb)89,800Kg (197,900lb)
Maximum Landing Weight54,657Kg (120,499lb)58,604Kg (130,000lb)66,349Kg (146,275lb)66,349Kg (146,275lb)66,043Kg (145,600lb)69,309Kg (152,800lb)69,309Kg (152,800lb)74,344Kg (163,900lb)TBA
Max. Zero Fuel51,709Kg (113,999lb)55,202Kg (121,700lb)62,721Kg (138,276lb)63,628Kg (140,276lb)62,913Kg (138,700lb)65,952Kg (145,400lb)65,952Kg (145,400lb)70,987Kg (156,500lb)TBA
Fuel
Capacity (Litres)26,035L, (6,878 US Gal)26,035L, (6,878 US Gal)
Speeds
Vmo/Mmo Velocity/Mach Maximum Operating speed340/0.82340/0.82
Cruise Speed IAS/Mach230/0.785230/0.785
True Airspeed450Kt450Kt
Ceiling (Ft)41,00041,000
Range with Max Payload NM(Km)4,500 (8,334)4,400 (8,149)4,000 (7,408)3,200 (5,926)3,850 (7,130)3,550 (6,570)3,300 (6,110)
Variant600700800900Max 7Max 8Max 200Max 9Max 10
FAMILYNEXT GENERATION (NG)737 MAX
Malaysia Airlines Boeing 737-800 Registration 9M-MXA

Malaysia Airlines Boeing 737-800 Registration 9M-MXA.

Boeing 737 MAX Points of Difference.

3d_blue_planeA change to the tail cone to a more tapered aerodynamic shape. This is part of the design improvement to realise an up to a 1% improvement in fuel economy.
3d_blue_planeBoeing 787 like engine nacelles with a scalloped casing which allows for a cleaner airflow and less drag.
3d_blue_planeA split winglet with fins pointing up and down which reduces weight by a less robust structure required for two smaller fins. It also ensures that the aircraft can still utilise ICAO gate reference C gates ( wingspan - 24m (78.7') - <36m (118.1') ) whilst enjoying a greater wing area for higher lift and therefore lower fuel consumption.
3d_blue_planeLeap-1B engines with a larger fan diameter of 1.76 Metres (69.4 in).
3d_blue_planeAn increase of 8 inches in length to the nose wheel strut to accommodate the larger diameter engines. This ensures a 43CM (17 IN) clearance between the bottom of the engine casing and the runway surface.
3d_blue_planeA redesigned and lengthened engine pylon to further accommodate the larger engines. The new Leap 1B engines are positioned further forward and slightly higher than their predecessors to accommodate their larger diameter.
3d_blue_planeA general strengthening of the airframe structure.
Lion Air Boeing 737 MAX 8 Reg PK-LQM with its Leap 1 engines in reverse thrust.

Lion Air Boeing 737 MAX 8 Reg PK-LQM with its Leap 1 engines in reverse thrust.

The Boeing 737 Max family of aircraft. Note the new winglets or wing fins. Weight is saved by a less robust structure required for two smaller fins.

The Boeing 737 Max family of aircraft. Note the new winglets or wing fins. Weight is saved by a less robust structure required for two smaller fins.

In 1964 the concept of a cheaper twin-engined jet transport was floated by Boeing.  Building on the designs of the Boeing 707 and Boeing 727, the concept came to fruition in 1967 in the form of the Boeing 737-100. The initial specification called for 50 - 60 seats, however, in consultation with launch customer Lufthansa, who had 21 aircraft on order, this was increased to 100 seats. Only 30 Boeing 737 100s were produced.

In April 1965 United Airlines placed an order for 40 aircraft but they required a slightly larger version.  Boeing complied by stretching the Boeing 737-100 design by 91cm (36 inches). This new variant became the Boeing 737-200 and was preferred by airlines compared to the 737-100.

A slow order book in 1970 caused Boeing to consider selling off the design. The cancellation of the Supersonic Transport project, however, freed up funds and Boeing offered a convertible version of the 737. Dubbed the Boeing 737C. This aircraft featured a 340 cm × 221 cm (130 in × 87 in) door just behind the cockpit which allowed for the loading of palletised cargo. The Boeing 737 QC (Quick Change) was also offered which enabled palletised seating and cargo. Airlines could fly passengers by day and then cargo by night. These models were offered in both Boeing 737-100 and Boeing 737-200 air-frames.

History.

US Airways Boeing 737-400

US Airways Boeing 737-400.

Toward the end of the 1970s, Boeing realised that to keep pace with the market they had to update and modernise the Boeing 737.

At the Farnborough air show of 1980, initial specifications for what would become the Boeing 737 300 were released. This aircraft was larger with a seating capacity of 149 and a lengthening of the fuselage by 2.87 metres (9ft 5in) as well as an increase to the wingspan of 53cm (1ft 9in).

The original Pratt and Whitney JT8D-1 low bypass engines which sat under the wing protruding fore and aft were replaced by CFM56-3B-1 high bypass engines. Due to the low ground clearance of the aircraft the engines were hung on pylons from the wings to sit ahead of the wings. The air intakes were also not circular but rather flattened at the bottom to aid with ground clearance. Wing aerodynamics were improved as well as the offering of IFIS (Electronic Flight Instrumentation Systems) cockpits.

October of 1988 saw a further stretch to the Boeing 737 in the form of the Boeing 737 400, a variant that added an additional 3 metres (10 feet) to the fuselage length thus enabling a 170-seat capacity.

Alaska Airlines 737-900 with The Spirit of Disneyland II colours registration N318AS

Alaska Airlines 737-900 with The Spirit of Disneyland II colours. Registration N318AS.

AeroMexico Boeing 737-800 registration N520AM landing at Miami FL(MIA) 17OCT2011

AeroMexico Boeing 737-800 registration N520AM landing at Miami FL(MIA) 17OCT2011.

Not all airline customers required the extra capacity offered by the newer versions of the Boeing 737. The Boeing 737 500 was launched in 1987 as a replacement for the Boeing 737 200. Being 48cm (1ft 7in) longer than the Boeing 737 200 and powered by the newer CFM56-3 high bypass engines the Boeing 737 500 showed a 25% fuel saving over the older variant.

The late eighties and early nineties saw serious competition offered by Airbus with their Airbus A320 model.  In 1991 Boeing began development on a new generation of aircraft. The Boeing 737 NG (Next Generation) group of aircraft includes the Boeing 737 600, Boeing 737 700, Boeing 737 800 and Boeing 737 900. This was the most significant update to the Boeing 737 so far, resulting in an all-new aircraft performance-wise, but still retaining important commonality with previous versions.

The wing was redesigned with greater chord and updated airfoil sections. The wingspan was increased by 4.9 metres (16 feet) giving a wing area increase of 25%. Coupled with the new CFM56-7B engines and increased fuel capacity, the range was increased by 900NM to 3,000NM. Winglets were also offered.

Modern avionics were offered as well as a modern cabin which was taken from the Boeing 777.

Boeing 737 MAX

As far back as 2005, Boeing initiated Project Yellowstone 1 (Y-1) to come up with an updated design building on the Boeing 737 Next Generation family. Incorporating technology from the Boeing 787 Dreamliner, the aim was to achieve fuel savings in the order of 20-25%. However, tests came back with results closer to 10%. It was found that you can't build a smaller Boeing 787 which is designed for different uses such as lower cycles(take-offs and landings) and carrying different systems for longer flights.

The project was shelved but not abandoned. New technologies had to be developed to enable the concept to become an actuality.

On 11 August 2011, the Boeing board approved the 737 Max development project. The new family of Boeing 737s would adopt the same variant numbering system as the 787, namely Boeing 737 Max 7, Boeing 737 Max 8, Boeing 737 Max 9, and Boeing 737 Max 10. The main driver, of course, was the need to come up with a newer more economical version of the iconic 737 city jet and remain competitive.

Airbus Industrie was well on the way to producing their new A320, the A320 NEO (New Engine Option) which would deliver a more economical version of the popular Airbus that is a direct competitor to the 737. After much research and analysis, it was determined that applying updates, improvements, and modifications to the current Boeing 737 model was by far the best option cost-wise and also speed-to-market-wise.

Boeing 737 MAX 8

Boeing 737 MAX 8 in Boeing house colours.

The first Boeing 737 Max -8 fuselage completed assembly on 13 August 2015 at the Spirit AeroSystems plant in Wichita, Kansas.

This was a test aircraft and was eventually delivered to launch customer Southwest Airlines.  The completed aircraft, named "Spirit of Renton" rolled out of the Boeing Renton Factory on 08 December 2015. Nearly 49 years after the first Boeing 737 took to the air on 09 April 1967. The 737 MAX -8 took to the air on its first flight on 29 January 2016.

Boeing 737-9 MAX CFM LEAP-1B engine. The chevroned rear of the nacelle, like the Boeing 787, ensures a smooth laminar airflow over the engine casing. This is all part of the 737 MAXs fuel-saving economy.

Instrumental to delivering a more economical and powerful 737 is the CFM Leap 1B engine. This new generation engine uses the latest technology to deliver the cost savings that will take the 737 into the 21st Century. However, as has been the problem in the past with the low ground clearance 737, adding a larger engine has its own challenges. If you look at current 737s, like the 737-800 for example, you will notice that the engine nacelle is flattened at the bottom. This is to enable enough ground clearance. The Leap 1B is larger again. To enable it to be fitted to the 737 Max, the engine has been fitted to a pylon that holds the engine further forward from the wing and therefore can be set higher off the ground. 

In addition, the nose wheel strut has been extended by 8 inches to lift the engines higher.  The engines being further forward has caused a change to the aircraft dynamics in certain phases of flight. In those flight phases, it was found that the nose of the aircraft might pitch up, bringing about the possibility of a stall. To guard against this, Boeing installed a new system called the Manoeuvring Characteristics Argumentation System (MCAS). This system is designed to prevent the possibility of the aircraft entering a stall in the above-mentioned flight phases. The MCAS uses the horizontal stabilizer trim to push the nose of the aircraft down in cases where it senses a high angle of attack that may lead to a stall.

This view shows the distinctive Boeing 737 MAX winglet. Two smaller winglets mean that there is less weight required than for a more robust single longer span. In addition, it means that a significant amount of wing surface is added whilst still being able to fit into Gate size C at airport terminals.

Have we seen the last of the Boeing 737 Max problems?

The loss of two 737 Max aircraft with the tragic loss of hundreds of lives sent a clear signal to Boeing and regulators that all was not as well as it should be. The travelling public puts their utter faith in aircraft manufacturers as they strap themselves into their seats. When things go wrong, it destroys that faith, so not only do the problems need to be rectified, but they have to be done so in a very public and transparent way to restore that faith.

So what has Boeing been doing?

The problem as we recall is to do with the MCAS (Maneuvering Characteristics Augmentation System) which is a system that kicks in to stop the aircraft from getting into a stall situation in some very specific sets of unusual flight conditions. The need for MCAS was mainly brought about by the larger Leap 1B engines having to be placed on a longer pylon further forward of the wing to enable the required ground clearance below the engine when taxying. This created a slight change to the aircraft's aerodynamics which Boeing recognised and created a system to protect against a possible stall with a higher-than-usual angle of attack.

Boeing 737-347 Atlant-Soyuz Airlines Reg VP-BBM

Boeing 737-347 Atlant-Soyuz Airlines registration VP-BBM

MCAS was designed to work in a situation where:

  • The pilot is hand-flying the aircraft.

  • The nose of the aircraft approaches a higher-than-normal angle of attack.

  • The wing flaps are not deployed.

What Boeing has done is build more fail-safes into the system so that it doesn't activate until several cross-checks have taken place. The updated features are:

  • Two Angel Of Attack sensors will have their data compared.

  • Each sensor will send its data to the flight control computer.

  • The computer will only activate MCAS if the data from both sensors agree.

  • The MCAS will only be activated once so that pilots can then handle the situation instead of repeatedly having to fly against the MCAS.

  • MCAS will never override the pilot's ability to fly the aircraft using the control column.

Boeing 737-33V EasyJet registration G-EZYO

Boeing 737-33V EasyJet registration G-EZYO.

How does this differ from the original configuration?

The original MCAS based its activation on the data of a single Angle Of Attack sensor reporting on the attitude of the aircraft. In the case of Lion Air and Ethiopian Airlines, the single Angle Of Attack sensor fed back incorrect data to the MCAS. The data was repeatedly sent back which caused the MCAS to keep re-engaging on the receipt of each incorrect signal. This of course completely confused the pilots as they could see no reason for the Angle Of Attack readings nor the aircraft taking control of them each time it happened.

KLM Royal Dutch Airlines Boeing 737-900A registration PH-BXO.

KLM Royal Dutch Airlines Boeing 737-900A registration PH-BXO.

You can see that both of those issues have now been addressed by Boeing. It is tragic, but often the way that lives have to be lost to move forward with technology.

As you can imagine, the Boeing 737 Max has now been scrutinised and rescrutinised to within an inch of its life. During that process, several other modifications have been mandated before an aircraft can go back into the air. Namely:

  • Software updates to avoid a theoretically possible runaway stabiliser condition.

  • Modify wiring in the horizontal stabiliser control system to be further apart to avoid the possibility of rubbing together.

  • Checking all stored aircraft for FOD (Foreign Object Debris). Some instances of FOD were discovered in stored aircraft.

  • Updates to software to avoid the remote possibility of autopilot disengagement.

The Boeing 737 Max is now in full production with orders looking healthy. If you have flown on a MAX be sure to let us know your thoughts below.

Air Europa Boeing 737-85P Registration EC-JBJ

Air Europa Boeing 737-85P Registration EC-JBJ.

A Boeing 737 History Timeline.

DateEvent
11 May 1964Original design work of Boeing 737 begins.
19 February 1965Lufthansa orders 21 aircraft becoming the launch customer.
05 April 1965United Airlines orders 40 Boeing 737s but wanting a longer version, the Boeing 737 200 is developed which is 193 centimetres longer than the original aircraft which is re-designated the Boeing 737 100.
December 1966Six Boeing 737 100 prototypes roll off the production line.
17 January 1967The first production Boeing 737 100 rolls off the production line.
09 April 1967The Boeing 737 100 makes its maiden flight.
29 June 1967The first Boeing 737 200 rolls off the production line.
08 August 1967The Boeing 737 200 makes its maiden flight.
15 December 1967The Boeing 737 100 receives certificate A16WE from the FAA (Federal Aviation Administration) for commercial flight.
21 December 1967The Boeing 737 200 received FAA certification.
28 December 1967The first Boeing 737 100 was delivered to Lufthansa. Only 30 Boeing 737 100s were ever produced.
28 April 1968United Airlines makes its inaugural flight of the Boeing 737 200 from Chicago to Grand Rapids.
May 1971The Boeing 737 200 Advanced was introduced, giving higher engine thrust and higher fuel capacity. This increased the payload and range over the original Boeing 737 200 by some 15 per cent.
20 May 1971The first Boeing 737 200 Advanced was put into service by All Nippon Airways.
June 1971The Boeing 737 200 Advanced became the standard for the production of the Boeing 737 200
31 July 1973The first military variant of the Boeing 737 200, designated T-43 was produced.
May 1982The Indonesian Air Force received the first of three Boeing 737 200 derivatives designated 737-2x9 Surveillers to be used for maritime surveillance. The type featured SLAMMAR (Side-looking Multi-mission Airborne Radar).
October 1983The Indonesian Air Force 737-2x9 order is completed.
24 February 1984The prototype of the Boeing 737 300, the 1,001st 737 built, makes its maiden flight.
19 February 1988The Boeing Boeing 737 400 makes its maiden flight.
08 August 1988The last Boeing 737 200 is delivered to Xiamen Airlines, 1,114 of the type having been produced.
30 June 1989The Boeing 737 500 makes its maiden flight.
28 February 1990Launch customer, Southwest Airlines took delivery of their first Boeing 737 500.
17 November 1993In response to competition from the Airbus A320, Boeing announced the Boeing 737 NG (Next Generation) aircraft.
08 December 1996The Boeing 737 700, first of the 737NG family rolls off the production line.
09 February 1997The Boeing 737 700, the 2,843rd 737 built, makes its maiden flight.
30 June 1997The Boeing Boeing 737 800 rolls off the production line.
31 July 1997The Boeing 737 800 makes its maiden flight.
December 1997The Boeing 737 600 rolls off the production line.
22 January 1998The Boeing 737 600 makes its maiden flight.
11 August 1998The business jet derivative of the Boeing 737 700 with modifications rolls off the assembly line designated BBJ (Boeing Business Jet) (later BBJ1).
18 September 1998The first production Boeing 737 600 is delivered to launch customer, Scandinavian Airlines
26 July 1999The final Boeing 737 500, the 389th aircraft of the type produced, was delivered to All Nippon Airways.
17 December 1999The Final Boeing 737 300, the 1,113th aircraft of the type, is delivered to Air New Zealand.
25 February 2000The final Boeing 737 400, the 486th aircraft of the type, was delivered to CSA Czech Airlines.
28 February 2001The first Boeing business jet designated BBJ2 and based on the Boeing 737 800 is delivered.
15 May 2001Alaska Airlines takes delivery of the first Boeing 737 900, so far the most powerful Boeing 737 built.
14 June 2004Boeing wins the tender to replace the P3-Orion maritime patrol aircraft with the Boeing 737 800ERX (Extended Range). It is designated P8- Poseidon.
30 January 2006Boeing launches the Boeing 737 700ER.
13 February 2006Boeing delivers the 5,000th Boeing 737 to Southwest Airlines.
08 August 2006The first Boeing 737 900ER rolls of the Renton, Washington assembly line.
16 February 2007Launch customer All Nippon Airways receives its first Boeing 737 700ER
27 April 2007Lion Air of Indonesia take delivery of the first Boeing 737 900ER
31 March 2008The final Boeing 737 200 services are phased out after 40 years of service.
July 2008From now on all Boeing 737s are fitted with carbon brakes manufactured by Messier-Bugatti. Weighing 250-320Kg (550-700lb) less than the previously used steel brakes they represent a 0.5% reduction in fuel burn on a Boeing 737 800.
August 2008The first Boeing business jet designated BBJ3 based on the Boeing 737 900ER is produced.
April 2009Boeing delivers the 6,000th Boeing 737 to Norwegian Air Shuttle.
20 July 2011Boeing announces plans for a new Boeing 737 variant to be powered by CFM International Leap X engines.
30 August 2011Boeing confirms the plans to produce the Boeing 737 MAX powered by CFM International Leap 1B engines.
13 December 2011Southwest places an order for the Boeing 737 MAX thus becoming the launch customer.
23 July 2013Boeing confirms the firm configuration of the 737 MAX8.
September 2014Boeing the launches a high-density seating version of the 737 MAX8, the 737 MAX8 200. The 200 represents the 200 seat configuration.
13 August 2015The first 737 MAX fuselage was completed at Spirit AeroSystems, Wichita, Kansas.
08 December 2015First 737 MAX8 rolled out at the Boeing Renton Factory.
29 January 2015Maiden flight of the Boeing 737 MAX8.
08 March 2017The Boeing 737 MAX is awarded F.A.A. Certification.
27 March 2017The Boeing 737 MAX is awarded E.A.S.A. Certification.
06 May 2017The first Boeing 737 MAX is delivered to Malindo Air (Malaysia).
22 May 2017Malindo Air places the first 737 MAX into service as flight OD803 from Kuala Lumpur to Singapore.
19 June 2017Boeing launches the 737 MAX10.
15 July 2017First Trans-Atlantic flight of the 737 MAX by Norwegian Air International. The aircraft was named Sir Freddie Laker.
29 August 2017Launch customer Southwest Airlines takes delivery of their first 737 MAX.
22 November 2017Assembly begins of the first 737 MAX7 test aircraft.
05 February 2018The first 737 MAX7 aircraft rolls out of the Renton factory.
February 2018The configuration of the 737 MAX10 is firmed up.
16 March 2018Maiden flight of the Boeing 737 MAX7.
29 October 2018A 737 MAX8 of Lion Air, flight 610, Reg. PK-LQP, crashed into the Java Sea off Jakarta after a flight of only 13 minutes.
November 2018The first 737 MAX8 200 rolled out of the factory door for Ryan Air. They ordered 135.
13 January 2019Ryan Air's first 737 MAX8 200 departs Renton.
10 March 2019A 737 MAX8 of Ethiopian Airlines, flight 302, Reg. ET-AVJ, crashed only 6 minutes after departing Addis Ababa.
13 March 2019After several other countries had already banned them, the F.A.A. grounded all 737 MAX aircraft flown by U.S. airlines or from being flown in U.S. and territories airspace. The F.A.A. cited new information being the reason, not pressure.
18 November 2020FAA Administrator Steve Dickson signs the order that will begin the Boeing 737 MAX's journey back to service. This follows a 20 month review process conducted by staff of the FAA. The return to service is subject to instructions in a new Air Directive being carried out. Furthermore a Continued Airworthiness Notification to the International Community has been issued along with new Training Requirements. This is not an automatic return to service. The FAA will review the updated training curriculum of each airline operating the MAX.
29 December 2020American Airlines resumes sevices with a flight from Miami to New York, La Guardia.
11 February 2021United Airlines resumes 737 Max services.

The Boeing 737 is configured in a six-abreast seating arrangement, with three on either side of the aisle.

In its inception, the Boeing 737 was competing with many airliners which had five abreast seating configurations with two on one side and three on the other of the aisle. This made it feel more like the intercontinental airliners of the day, the Douglas DC8 and the Boeing 707.

The cabin can be accessed by four doors. One on each side immediately behind the cockpit, and one on either side at the very rear of the cabin. Two overwing emergency exits on each side of the cabin consist of removable hatches slightly larger than the windows they encompass which can be removed and thrown out of the cabin.

Cabin Interior.

A Boeing 737 standard interior.

A Boeing 737 standard economy interior.

Food preparation areas exist at the front and rear of the cabin along with lavatories.

Depending on the airline and the routes for which the aircraft has been intended, the interior can be spartan with no in-flight entertainment system for short shuttle type routes.

In response to customer surveys, Boeing has come up with the most dramatic improvement to the cabin of a single-aisle airliner.

A Fly Dubai 737 800 with a Sky Interior.

A Fly Dubai 737 800 with a Sky Interior.

A Fly Dubai 737 800 with a Sky Interior.

The Sky interior comprises design improvements that give a much greater impression of space than the standard offering.  New larger stowage bins allow for more carry-on baggage whilst at the same time being less obtrusive as they sweep up to the ceiling.

Not only are the luggage bins less obtrusive but they are actually larger inside than the previous versions.  Space Bins as Boeing calls them, which are manufactured by Boeing and not an outside manufacturer, are capable of stowing a carry-on wheelie bag "end on".  This means that instead of the four-bag limit offered by the old-style bins, the new Space Bins can store six such bags.

Boeing 737 Sky Interior cutaway.

Boeing 737 Sky Interior cutaway.

Lighting is now provided by LED (Light Emitting Diodes) lights which are brighter but can also vary in brightness to change the cabin mood from white to soft sunset colours. These lights have a life of around 40,000 hours instead of the 4,000 offered by traditional bulbs.

The side walls have also been changed to give the impression of space, along with improvements to the layout and location of the PSU (Passenger Service Unit) for air, sound, and cabin attendant call buttons.

Fly Dubai was the launch customer for the Sky Interior and is one of 45 airlines that have ordered some 1,180 aircraft with these interiors which account for around half of Boeings’ unfulfilled 737 orders. Other airlines which have opted for the Sky Interior are Malaysia Airlines, Jetairfly, Continental Airlines, and Norwegian Air Shuttle.

Orders and Deliveries.

As you can see, the order book for the 737 Max is filling very rapidly and looks to be a very successful product for Boeing. We are also noticing that the orders for the 737-800 have reduced which leads us to believe that many 737-800 orders have converted to 737 MAX orders.  All this as we pass 11,000 737s being produced overall.

VariantOrdersDeliveries
Boeing 737-1003838
Boeing 737-2001,1601,114
Boeing 737-3001,3391,113
Boeing 737-400532486
Boeing 737-500514389
Boeing 737-6006969
Boeing 737-7001,4081,128
Boeing 737-700C2222
Boeing 737-700W1614
Boeing 737-8005,4414,989
Boeing 737-800A191168
Boeing 737-9005252
Boeing 737-900ER577505
Boeing 737-MAX6,8161,033
Totals18,17511,112

Correct as at 31 December 2022

A Westjet Boeing 737 MAX 8 under a forbidding sky.

A Westjet Boeing 737 MAX 8 under a forbidding sky.