|Modifying the current model||Specs for the Boeing 737 Max||737 Max Features|
|Timeline of the Boeing 737 MAX||Specs for the Boeing 737 Max||Have we seen the last of the Boeing 737 Max problems?|
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.
Modifying the current model.
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.
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.
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.
With an eye on cost savings for airlines, Boeing tried as much as possible to keep cockpit configuration the same as previous models. This way pilots can rotate from previous 737 models to the new Max with minimal retraining required.
The new design has some obvious visual differences which include:Top
737 Max Features
|A 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.
|Boeing 787 like engine nacelles with a scalloped casing which allows for a cleaner airflow and less drag.
|A 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.
|Leap-1B engines with a larger fan diameter of 1.76 Metres (69.4 in).|
|An 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.
|A 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.
|A general strengthening of the airframe structure.|
A timeline of the Boeing 737 MAX
|30 AUG 2011||Launch of the Boeing 737 MAX Project.|
|23 JUL 2013||Firm configuration of the 737 MAX8 confirmed by Boeing.|
|SEP 2014||Boeing launches a high-density version of the 737 MAX8, the 737 MAX8 200, which stands for 200 passengers.|
|13 AUG 2015||The first 737 MAX fuselage was completed at Spirit AeroSystems, Wichita, Kansas.|
|08 DEC 2015||First 737 MAX8 rolled out at the Boeing Renton Factory.|
|29 JAN 2016||Maiden flight of the Boeing 737 MAX|
|08 MAR 2017||The Boeing 737 MAX is awarded F.A.A. Certification.|
|27 MAR 2017||The Boeing 737 MAX is awarded E.A.S.A. Certification.|
|06 MAY 2017||The first Boeing 737 MAX is delivered to Malindo Air (Malaysia).|
|22 MAY 2017||Malindo Air places the first 737 MAX into service as flight OD803 from Kuala Lumpur to Singapore.|
|19 JUN 2017||Boeing launches the 737 MAX10.|
|15 JUL 2017||First Trans-Atlantic flight of the 737 MAX by Norwegian Air International. The aircraft was named Sir Freddie Laker.|
|29 AUG 2017||Launch customer Southwest Airlines takes delivery of their first 737 MAX.|
|22 NOV 2017||Assembly begins of the first 737 MAX7 test aircraft.|
|05 FEB 2018||The first 737 MAX7 aircraft rolls out of the Renton factory.|
|16 MAR 2018||Maiden flight of the Boeing 737 MAX7.|
|FEB 2018||The configuration of the 737 MAX10 is firmed up.|
|29 OCT 2018||A 737 MAX8 of Lion Air, flight 610, Reg. PK-LQP, crashed into the Java Sea off Jakarta after a flight of only 13 minutes.|
|NOV 2018||The first 737 MAX8 200 rolled out of the factory door for Ryan Air. They ordered 135.|
|13 JAN 2019||Ryan Air’s first 737 MAX8 200 departs Renton.|
|10 MAR 2019||A 737 MAX8 of Ethiopian Airlines, flight 302, Reg. ET-AVJ, crashed only 6 minutes after departing Addis Ababa.|
|13 MAR 2019||After 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 NOV 2020||FAA 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 DEC 2020||American Airlines resumes sevices with a flight from Miami to New York, La Guardia.|
|11 FEB 2021||United Airlines resumes 737 Max services.|
Specs for the Boeing 737 Max
|Maiden Flight||16 March 2018||29 January 2016
||13 April 2017||18 June 2021|
|Launch Delivery||Expect 2022||May 2017||21 March 2018
|Launch Airline||Southwest Airlines(deferred). Westjet expected 2022.||Malindo Air (Sub. Lion Air)||Lion Air||tba|
|First Delivery||Expect Jan 2019||16 May 2017
|In Current Service|
|Passenger Capacity||172 (Maximum seating)
150 (1-class, average)
138 (2-class, average)
|210 (1-class, high volume)
174 (1-class, average)
178 (2-class, average)
|220 (1-class, high volume)
177 (1-class, average)
178 (2-class, average)
|204 (2 Class average) 230 1-class average)|
|Power Plant||CFM International|
|Fan Tip Diameter||1.76 m (69.4in)|
|Thrust||26,786–29,317 lbf (119–130 kN)|
|Fuselage Length||35.56 M (116 ft 8 in)||39.47 M (129 ft 6 in)||42.16 M (138 ft 4 in)||43.80 M (143 ft 8 in)|
|Overall Height||12.3 M (40ft 4in)|
|Wing Span||35.92 M (117 ft 10 in)|
|Wing Area||127 m2 (1,370ft2)|
|Overall Height||12.3 M (40ft 4in)|
|Max. Zero Fuel Weight||62,913kg(138,700lb)||65,952kg(145,400lb)||70,987kg(156,500lb)||TBA|
|Max. Takeoff Weight||80,286kg (177,000lb)||82,191kg (181,200lb)||88,314Kg (194,700lb)||89,765Kg (197,900lb)|
|Maximum Landing Weight||66,043kg(145,600lb)||69,309kg(152,800lb)||74,344kg(163,900lb)||TBA|
|Capacity (Litres)||25,816L(6,820 US Gal), excluding Auxiliary Centre Tank|
|Cruise Speed IAS/Mach||Mach 0.79 (453 kn / 839 km/h)|
|Ceiling (Ft)||41,000 ft (12,000 m)|
|Range with Max Payload(nm)||7,130 Km (3,850 Nm)||6,570 Km (3,550 Nm)||6,570 Km (3,550 Nm)||6,110 Km (3,300 Nm)|
|Takeoff (MTOW, ISA)||2,100 m (7,000 ft)||2,500 m (8,300 ft)||2,600 m (8,500 ft)||TBA|
|Landing (MLW, dry)||1,500 m (5,000 ft)||1,500 m (5,000 ft)||1,700 m (5,500 ft)||TBA|
|Cargo Capacity||32.3 m3 1,139 ft3||43.6 m3 1,540 ft3||51.3 m3 1,811 ft3||55.5 m3 1,961 ft3|
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. It 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 fight 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.
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 off them each time it happened.
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 in the air. Namely:
- Software updates to avoid a theoretically possible runaway stabiliser condition.
- Modify wiring in the horzontal 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 dicovered in stored aircraft.
- Updates to software to avoid the remote possibility of auto pilot 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 how you felt about it.Top
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