TBT – A look at the Boeing 737 MAX

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This week’ s Throwback Thursday from the April 2016 edition of Australian Aviation looks at the development of {the latest|the most recent|the newest} iteration of the Boeing 737 program.

The Boeing737 MAX 8. (Boeing)

Somewhere {across the world|around the globe|around the world} a Boeing 737 {takes off|will take off} or lands every five seconds and more than 1, 200 of their compatriots are aloft at any given time. With the {total number|count|amount} of Boeing 737s {that have been|which have been|which were} built approaching 9, 000, this twin-engined airliner has truly earned the term ‘ prolific’ to be used in its description. And while the maiden flight of the 737-100 took place in 1967, there is no sign {of the|from the|in the} 737’ s popularity abating as evidenced by the rise of its latest offspring – the 737 MAX.

The 737 design has been tried and tested for nearly {50 years|5 decades}. With each generational change, Boeing has sought {to build|to create|to develop} upon the core product and enhance it {with the|using the|with all the} newest technologies on hand, {and the|as well as the|plus the} 737 MAX is the ultimate example of this.

In the modern era, efficiency {is the key|is vital|is key} requirement for airlines. They want their aircraft to be leaner and greener and yet possess an enhanced level of performance. {As a result|Consequently|Because of this}, manufacturers look towards the age-old challenges of weight and drag and their co-existence {with the|using the|with all the} pursuit of power. Consequently, three major areas contribute to the answers – aerodynamic design, powerplant and materials.

The eye-catching feature {of the|from the|in the} 737 MAX is the new style winglets. While airlines started retro-installing split scimitar winglets on 737s in 2014, the new Advanced Technology (AT) all-composite winglets were exclusively designed as part of the 737 MAX wing. All 737 MAX aircraft will be delivered {with the|using the|with all the} AT winglets as standard and alone they contribute up to 1 . 8 {per cent|%|percent} in fuel savings.

With their greatest efficiency in the cruise, the longer the flight, the greater {the benefit|the advantage|the main benefit}. Interestingly, the ailerons and tabs found inboard {of the|from the|in the} AT winglets will be {produced by|created by|made by} Boeing Aerostructures Australia in Port Melbourne.

The 737 MAX features new split tip winglets. (Boeing)

The 737 MAX features new split tip winglets. (Boeing)

At the heart {of the|from the|in the} 737 MAX is the {new technology|new-technology} CFM LEAP-1B engine. Throughout aviation history, successful aircraft have always been characterised by a strong, well-matched combination of airframe and powerplant and the 737 {is no|is not any|is not a} exception.

Growing out of the tremendous success {of the|from the|in the} established CFM56 engine, the LEAP possess a fan diameter that is 23cm greater than its predecessor. Thrust ratings {on the|around the|within the} 737  MAX LEAP-1B engines are about 1, 000lb higher than the same ratings {on the|around the|within the} 737NG and range between 23, 000lb and 28, 000lb.

{Even so|However|Nevertheless}, while increasing the power output, the latest quiet engine technology will still result in an approximately 40 per cent {reduction in|decrease in|lowering of} community noise. The LEAP combustor also reduces NOx emissions by 50 {per cent|%|percent} compared to current CFM56 engines with identical overall pressure ratio.

{All the while|Even while|Whilst}, the LEAP-1B will provide a 15 per  cent specific fuel consumption (SFC) improvement over the CFM56 engine which, when combined with other 737  MAX enhancements, results in {an overall|a general} fuel efficiency improvement of 14 per cent compared to current production 737NGs (and {more than|a lot more than|greater than} 20  per cent over early-build NGs).

Central to the LEAP-1B’ s success are advances in engine technology including the use of new materials. The LEAP engine will be the first to introduce ceramics matrix composites (CMC) into commercial service. The engine will feature a CMC shroud in the first stage of the high-pressure turbine. Interestingly, it takes 150, 000 miles of carbon fibre to create a single LEAP fan blade, but that one blade is so strong it can support the weight {of a|of the|of any} Boeing 787.

The 737 MAX is powered by CFM International Leap-1B engines. (Boeing)

The 737 MAX is powered by CFM International Leap-1B engines. (Boeing)

What’ s in a name?

When the 737 Next Generation (NG) first emerged from the production line, its tall, blended winglets immediately caught the eye. The new AT winglets are equally noticeable, but the development of the MAX extends well beyond these aerodynamic devices. And in {the same|exactly the same|a similar} manner that the NG built upon the original ‘ classic’ 737, many of the MAX’ s new features are seamless {for the|for that|for your} crews that operate them. Consequently, NG pilots {will only|will simply|is only going to} require minimal classroom training to be qualified on the MAX.

Some of the {changes to|becomes} be incorporated in the MAX’ s systems include fly-by-wire (FBW) spoilers, an electronic bleed air system and larger flightdeck instrument displays. The fly-by-wire spoiler actuation sends electrical signals rather than the previous mechanical system, with a corresponding {reduction in|decrease in|lowering of} weight. Similarly, the bleed air system that controls cabin pressurisation and ice protection systems was previously pneumatically controlled. The new electronic system allows for increased optimisation {which in turn|which|which often} equates to improved fuel efficiency.

Deeper {into the|in to the|to the} digital workings of the MAX exist further developments. The MAX will include an enhanced onboard network system (ONS) comprised of a network file server (NFS) and an enhanced digital flight data acquisition unit (eDFDAU).

These systems {will provide|will give you|provides} a new set of capabilities to process data in real time {and will also|and also} leverage the available connectivity for secure communications with ground‑ based systems. {This will|This can|This will likely} support airline operations {such as|like|for example} remote software part transfers from the airline back office, or analytic capabilities {with the|using the|with all the} Boeing Airplane Health Management (AHM) system and {an electronic|an electric} logbook (ELB).

The 737 MAX {will provide|will give you|provides} real-time data to the ground about its systems during flight, making it easier for airlines to make operational decisions around maintenance. On the ground, the MAX features a more centralised built-in test equipment (BITE) system that technicians can access after a flight. The MAX will have additional systems reporting BITE and maintenance data so technicians can better assess dispatch limitations and maintenance actions.

Yet {for all the|for all your|for the} new developments, there are still commonalities with the NG. Firstly, the fuel capacity of the 737 MAX is the same {on the|around the|within the} NG 737 models. {Even so|However|Nevertheless}, the MAX will extend the NG’ s range to fly more than 3, 500nm, equating to an increase of 340-570nm thanks to the improvements in efficiency.

Common ground with the NG means that a significant percentage {of the|from the|in the} 737 NG spares that airlines already possess will carry over to the 737 MAX. Similarly, while the engines and winglets draw upon new materials, a good many components elsewhere have been kept common to the NG.

For passengers, the Boeing Sky Interior that comes as {an option|a choice|an alternative} on the NG will be standard on the 737  MAX.

An aerial view of the first Boeing 737 MAX on the final assembly line in September 2015. (Boeing)

An aerial view of the first Boeing 737 MAX {on the|around the|within the} final assembly line in September 2015. (Boeing)

The business end

The 737 MAX is available in four models – the 737-7, -8 and -9 (which share {the same|exactly the same|a similar} fuselage lengths as the 737-700, -800 and -900 respectively), plus the MAX 200 , a high density, 200‑ seat version {of the|from the|in the} 737-8 aimed at low‑ cost carriers. In a single-class layout the 737-7 seats 144, the 737‑ 8 seats 184, and the 737-9 204.

The MAX order book has grown steadily and now stands at 3, 072 orders to date and spanning 62 customers worldwide. Of the four models available, the 737-8 is – like the 737-800 before it – proving the most popular {with more than|using more than|exceeding} 2, 600 aircraft on order. Locally, Virgin Australia has orders for 40 737‑ 8s , due for delivery from 2018, while Air Niugini recently signed up for four.

On January 29, the first Boeing 737 MAX, with its new LEAP-1B engines and its distinctive winglets, and proudly bearing the Spirit of Renton name, took to the skies for the first time . {It was|It had been|It absolutely was} an event that was beamed live across the internet and caused quite a stir on {social media|social networking|social media marketing}. With 737 MAX chief pilot Ed Wilson and Boeing chief test pilot and vice president of flight operations Craig Bomben {on board|aboard|on side}, the MAX undertook {an initial|a preliminary|a basic} flight lasting nearly three hours.

{During the|Throughout the|Through the} flight, the 737 MAX reached a maximum altitude of 25, 000ft and an airspeed of 250kt, which is typical of a first flight sequence. The crew tested the aeroplane’ s systems and structures while onboard equipment transmitted real-time data to a flight test team on the ground in Seattle.

N8701Q takes off from Renton Field. (Boeing)

N8701Q takes off from Renton Field. (Boeing)

Boeing Commercial Airplanes senior vice president and general manager for airplane development Scott Fancher subsequently detailed how the 737 MAX program was progressing {ahead of|in front of|before} schedule and described {the first|the very first|the initial} test flight as “ flawless”.

“ The pilots reported the airplane behaved exactly as we expected, no drama. That’ s what I call {a successful|an effective|an excellent} first flight, ” Fancher told reporters during a media briefing at the Singapore Airshow in late February.
{With the|Using the|With all the} other three members {of the|from the|in the} 737 MAX 8 flight test fleet currently {in different|in various|in several} stages of final assembly {and the|as well as the|plus the} second MAX making its maiden flight on March  4, the 737 MAX remains on track for first delivery to Southwest Airlines in  2017.

The {start of the|start of} flight testing and the commentary about the good progress of the MAX certification program has raised speculation the manufacturer may be in a position to {deliver the|provide the|offer the} first aircraft to launch customer Southwest Airlines {before the|prior to the|ahead of the} publicly stated third quarter of 2017.

However , Boeing’ s Fancher did decline to offer any guidance when asked {how far|how long|what lengths} ahead Boeing was {on the|around the|within the} MAX flight test program or if the company had any discussions with airlines about potential early deliveries.
“ {I am|We are|I will be} not going to comment on discussions {we may|we might|organic beef} or may not have had with customers, ” he said at Singapore.

{For now|For the time being|For the moment}, Boeing will methodically expand the flight envelope {in order to|to be able to|so as to} prepare the rest of the flight test fleet to progress through different test conditions including takeoff performance, NAMS (nautical air mileage), ground effects, community noise and different environmental conditions including high altitudes, hot and cold temperatures and cross‑ winds.

Furthermore, in the flight test program, Boeing has built {into its|into their} testing plans a phase where it will “ operate like an airline” to simulate airline operations in revenue service to validate the aircraft design, maintenance manuals and on-board products prior to entry into service. The program {consists of|includes|contains} common airline practices and use of customer manuals, equipment and tools. In service, the 737NG has achieved an enviable schedule reliability record of 99. 7 {per cent|%|percent} and this is a record the MAX is working hard {to build|to create|to develop} upon as delays and cancellations equate to loss of both revenue and the goodwill of passengers.

Boeing 737 MAX 8 N8701Q landing at Boeing Field. (Boeing)

Boeing 737 MAX 8 N8701Q landing at Boeing Field. (Boeing)


The original 737 has been described as a ‘ classic’, while its wingleted offspring heralded in the Next Generation. Now, the 737 MAX {will be|is going to be|will probably be} 14 per cent more fuel-efficient than today’ s 737 NGs, flying farther, quieter and with less impact on {the environment|the surroundings|environmental surroundings}.

The newest breed has now arrived and is {set to|started|going} not only carry with it {all that is|everything is|everything that is} good about the 737 {but to|but for} go even further and {take it|get it|bring it} to the MAX.

[embedded content]
VIDEO: A look at the first flight {of the|from the|in the} Boeing 737 MAX 8, from the manufacturer’ s YouTube channel .

This story first appeared {in the|within the|inside the} April 2016 edition of Australian Aviation. To read more stories like this, {become a member|are a member} here .