The Sweet Spot

Hello 68. That’s the magic number everyone has been waiting for since the day we introduced the 737 MAX back in August. Today, we announced that we’re going with a 68-inch fan for the engine on this new variant of the world’s best-selling airplane.


New image: A 737 MAX is shown in the foreground as a Next-Generation 737 flies overhead.

Our CEO Jim Albaugh calls it the sweet spot and I couldn’t agree more. That 68-inch fan size, in combination with how we mount the engine on the wing, allows us to optimize the MAX for the best fuel efficiency and lowest operating costs. It also allows us to stay well ahead of our competition’s current and future offerings.


Why 68” is just right.

While we’re keeping the design scope of the MAX program as small as possible, there will be a slight adjustment to the nose gear. While some people think that may be a big deal, think of it this way. Boeing has a long history of integrating engines and wings. All you have to do is look at our employees who just finished two development programs in the same year. We’re fully prepared to start work on the MAX.

During my trip to Southeast Asia this week and wherever I travel the world, I’ve seen and heard the interest in the 737 MAX from customers, media and shareholders. The strong demand is best seen in the latest numbers—more than 600 order commitments from eight airlines. We expect to see hundreds of more commitments in the coming months. The buzz about the 737 MAX is just beginning and I expect it to only grow as we get closer to our expected first flight in 2016.

Comments (43)

David Balton (Ft.Lauderdale, Fl. USA):

Hi Randy

Another advantage of Boeing vs "the Competition" often overlooked but important to passengers like myself who like to fly and sit by the window---Boeing aircraft have bigger windows than the competion! You should point this out more often!

Vaidya Sethuraman (Chicago):

I think, Boeing finally got it right for 37 Max /RE how ever you call it. As you point out, the inherent weight advantage over 320 neo is very much there; sure, the 78 " fan will bring the Neo back up in double digits, but the 68" will keep the relative advantage going- engine dia is not the only driver, with weight and drag et al coming into play.
Hope -9 Max will improve the range significantly - so that it will have some good share of the 57 replacement market , where 321 is clearly a big player.
is it true that the MAS will be a full fly by wire plane ( one control surface et al)- not sure.Forthe big 37 boys like South West, this is just about perfect for the next jump in overall cost efficiencies.

James Baloun (Palo Alto, California, USA):

The 737 has become an example of an airframe achieving its Max potential. It started out in 1968 as a good aircraft, and after decades of improvement and refinement, Boeing has out-done itself to again make it even better. As an aerospace engineer Boeing's work is much appreciated. I agree with Vaidya, I hope the Max can fill the 757s shoes considering that the 757 was most definitely in the sweet spot.

V V (Montréal, Québec):

If I understand well, the engines will be tailor-made for the 737MAX. The fan is smaller than the one for A320neo and the core will also be different.

If the engine is correctly made the Specific Fuel Consumption (Sfc) of your LEAPX could well be very close to Airbus' LEAPX, despite the smaller fan diameter.

I still remember when I was much younger and when I used to play with simplified COC model, I had OEW (Operating Empty Weight) in the equations. If my memory serves me well, when the OEW increases, the COC increases as well. Not sure about the exact explanation.

Ron Aryel (Reno, NV):


Boeing hass a lot of work to do to catch up to Airbus' sales. As a former stockholder of Boeing, I certainly hope the 737MAX's technical superiority is appreciated by the airlines. Airbus closed sales for 1,200 single-aisle jets, and Boeing hasn't come close to matching that yet, possibly because the company pulled the trigger very late. Former CEO Phil Condit made that same mistake years ago - I would think your organization would have learned from that experience. I certainly wish you well in your endeavors.

Chip Lewinthal (Washington, DC, USA):

The one thing that would make the 737 Max even sweeter is if you change the windows to be the same size as the 777 or, even better yet, the 787. That would be the absolute best!

Frank McAvennie (London):

Correct me if I'm wrong here but isn't it the case that the sole reason for going with a 68" fan is down to structural constraints on the aircraft, namely it cannot accommodate anything larger without major (and costly) re-design of the aircraft. I'm sure Boeing would have wanted to go with a much larger fan, had that been possible. Larger fan=higher bypass ratio=more fuel efficient and lower fuel burn, or do general principles not apply in this case?

Smaller fan sizes with lower bypass ratios will also make for a noisier aircraft. The benefits, as listed above, are only part of the equation.

Erik K. Weseman (Middlebury, VT, USA):

I congratulate Boeing on the new 737 MAX-family. Hopefully, other airlines such as Alaska Airlines, Delta Air Lines and United Airlines will consider ordering the new plane. Hopefully, the fuel burn and fuel consumption will not be higher than the current 737 NG-family. I believe the 737MAX-9 would be a good replacement for United's domestic routes such as those on all of its Hawaii routes and maybe allow new nonstop routes such as New York/Newark-Anchorage.

Russel Ahmed (Dhaka, Bangladesh):

Boeing Believes on continuous reengineering for highest customer efficiency. 737NG simply made the way to achieve lowest maintenance cost along with fuel improvement. Putting this concept into mind, Now 737MAX going to rock the sky with its 68inch concept. 737-900ER clearly made its vision quite effectively to compare with 757. I do believe 737-9MAX will give the highest customer satisfaction when competing with 321NEO. All about best innovation ideas with the best feedback from the engineering department that makes the journey towards ultimate perfection. ITS BOEING............FOREVER THE FRONTIER.....

Norman (Long Beach, CA):

The 737-9MAX would do very well as a 757 replacement for United/Continental Airlines, the 737-7MAX would do well for Southwest as a 737-300,500 and older 737-700 replacemant if they have not ordered already and the 737-8MAX would do well as an update for Ryanair's 737-800s and countless other airlines.

Gary M Joraanstad (Baton Rouge, LA):

I believe Boeing made the right decision to go with the re-engined 737, although I think they were a little late in making that decision. I also think Boeing would be smart not to talk about the 68 inch fan for the engine as the end all. It looks like they are making the same mistake they did when they were talking about building a brand new 737 vs making a re-engined 737. I have no doubts that they will find they have to go to the 71 inch fan engine to get enough cost savings to match their cost savings claim over Airbus. I don't think we will ever see a 68 inch fan 737. If I was Boeing, I would leave myself some wiggle room so it doesn't look like they got forced into the 71 inch fan engine like they were virtually forced to go with the re-engined 737.
Boeing retiree of 38 years.

tom (canada):

has southwest airlines commited yet to 737 MAX and if not what are they waiting for, the incredible fuel savings per aircraft per year, dont they have the largest number of 737 s in the world?

Stephen Higgins (Brisbane, Australia):


your article sounds like you are trying to convince yourselves that 737 MAX is better than the NEO. All things being equal would you have really chosen the 68in fan?

737MAX will be a good airplane as will the A320 NEO, but when you come to pitch it to potential customers I think your arguments stated above might convince the (often patriotic) general public, but it won't wash with experienced airline executives.

I also think the decision to keep with the exclusive engine deal with CFM is losing the company potential sales.

I guess a truer picture will emerge as to which is the best aircraft when we see selection made by existing airlines that are not constrained by their existing fleet.

Best regards

amjad al-zoubi (amman jordan):

thanks boeing and i wish you all the best but i hope the windo of the cockpit change and look like the 787 . and i hope the cabin width become like the 707 3.76 so we feel much comfortable all the best boeing and keep going on

Ronald Beck (Arvada, Colorado, USA)):

From what I have read about the 737 MAX, the customer will have a reliable and fuel efficient passenger plane. I have really liked flying on the 737-800 and 737-900's in service. The 737 provides better cabin comfort versus the A320 and A321. I did read the A320 NEO has been scooped up by LCC's and not many of the majors. I may be wrong but it could happen that the NEO market will soon be passed up by 737 MAX sales. The 737 is everywhere. I agree with the other comments about the 757 and hope the 737 MAX takes over.

Chris (Netherlands):

The A320 Neo has 1000 plus orders, maybe it has some good things too..
Personally I like the wider cabin of the A320, and the nose section of the 737 is so 1967..

Christopher Irizarry (San Juan, PR):

I wish the program the best, but I was really hoping to see a 757 replacement. I believe that 757 has what no other narrowbody has, range, power and capacity...!!!

Charles Janeke (Los Angeles, CA):

I recall the original 737 concept was servicing 2nd and 3rd tier hubs with low pressure tires and sod field capability a definitive feature. Therefore the truncated landing gear to augment ground effect, ground access and reduce landing/takeoff speed. Although the tertiary function never materialized the unique low-slung 737 features spawned the regional hub-and-spoke market in the seventies that drove the explosive demand and icon identity of the 737 and made SW a brand name. The advent of high-bypass fan engines subsequently elevated the 737 into a high capacity transcontinental workhorse in par with but substantially more thrifty than the 757. Tweaking the fan diameter (the MAXX) is therefore a natural evolutionary adaptation to the 737 platform.

aaron (norway):

As a frequent flyer i always smile when i board a boeing - not sure what it is but somehow i feel at home/safe. I think this new 737 will be great and can't wait to fly one

Courtland (Salt Lake City, UT):

Question... are the "new" MAX going to be quieter for the customer in the cabin than "the competition" every time I've flown on Competitors aircraft they've been quieter than the 737 2nd gen and nextgen... and not just somewhat it's extremely noticeable... what is the cause for this and what improvements are being considered for passenger comfort in this area?


Dave Slaten (Las Cruces NM):

@ V

The max will only be a partial fly by wire in order to keep type ratings managable.

@J Nothin can replace the mighty "57"! The 37 just does not have the wing. You can go coast to coast with an 800 but you need a big runway on departure to do it. The Max will have more thrust and range so the 9 Max may just get into the very bottom end of the 57's range and will be close on the talking baggage, but you'll still need a couple of miles of slab to get it up.

I sure do miss those SNA-JFK runs on Americans 752's That departure is what a low sweep super critical wing and tons of horsepower is all about!

Alberto Talgi (Guatemala):

The 737 max is amazing but I would like to see what type of aircraft will come after the 737 max and a320neo.

eric (chicago, il):

can we get a bigger flight deck? how about 68 inches of legroom up there?

Chris Campbell (South Africa):

I really liked the 757, your new 737 max sounds great, what is the anticipated seating and range?
I hope it all goes smoothly for 2016. Good Luck.

TC (Mount Vernon, WA):

If the nose gear gets raised 8", that should bring the plane to level as I believe it is currently nose down.

Can't argue the facts, efficiency goes up as fan area increases, aerodynamic efficiency goes down with weight and drag as fan area increases. Where do those two lines cross?

Airbus is putting a 78" fan on a 27K engine. That's 225 square inches per thousand. The A350-1000 has a 118" fan at 97K, which is only 143 square inches per thousand. What's the explanation for that?

MARIO (queretaro. mx):

great airplane. all 737s i've been in are smooth ride and low noise cabin. i'm really looking fwd to travel in this new plane. great american planes with great american engines. is it anything better?

Paulo M (Johannesburg, RSA):

All the best -- hopefully, the lessons of the just completed/certified programs remain fresh and are called upon, and hopefully all goes according to plan. It's substance over style..

Astonishing and noteworthy the 737 MAX and 747-8 are in product development, especially from a point of view of environmental costs. Two lines carrying a tremendous library on aviation history...

Khalil (Michigan):

You guys should make a Next Gen 757 Now that will get HUGE orders.

Varun G (Chicago Illinois):

Congratulations to the Boeing team, although I would have preferred a replacement plane for the 57. I believe that there is a bigger market for that currently. I congratulate the Boeing team and wish them well on this journey.

LE LEUNG (Wuhan, PRC):


I think 737'S fuselage and aisle can be more wider that makes passenger feel more comfortable, and the landing gear feeling can be more smooth.

hopefully 757NG looks like a small sized, single aisle 787 Dreamliner.

Unimeride Group

David Colleman (Denver, Colorado):

Well great plane, hope that this model changes really the old 737 NG, Airbus with the newest model gain orders from airlines like American that only operates Boeing, I wish to the Boeing team the best with this project.

Thomas V. Horstmann, Jr. (Portland, Oregon):

While Boeing seems to be on the right direction in regard to the MAX, it remains to be seen if they can extend the range and load capacity enough that it can serve as a narrow bodied replacement to the 757.

Further, hopefully they engineer in Dreamliner sized windows, optimize cabin comfort at the 6000 foot elevation level, and increase the cabin humidity. In short, creating a mini Dreamliner.

If they can do that, and get the aircraft to market in 2016, Boeing will regain control of the narrow-body segment of the market.



Saidu Chanchangi (kaduna. Nigeria.):

Well Done Boeing We really appreciate your effort for making it easy with the New generation Aircrafts to suit our business over here in Africa. I will surely patronise your Aircraft when starting my own Airline.
Good Luck.

Capt Eric Cheong (Singapore):

Hello Randy,
I have been flying Boeing Airliners since 1969 and am presently flying the Boeing 747-400, which incidentally I have been on since 1989, with Singapore Airlines.
My comment : I have never been disappointed with any of the Boeing Airliners, Boeing builds not only great planes but safe ones.

Richard Campbell (Nassau,Np,Bahamas.):

Am a big fan of boeing and the 737max,
must offer more than the competion.Not only in fuel but in its design over all.A new front would be an excellent advantage giving the 737 a bold new look and feel.And a brand new paint job,good luck on your new 737 max.Just remember max means a hold lot more,
can't wait to see what you guys come up with GOOD LUCK.

Kristian (Slovakia):

Hi Randy. I have a question about the size of the cockpit compared to the A320. Many people say that the A320 has a larger and more comfortable cockpit. I've never flown at the A320. What do you think about comfort and space in 737 cockpit compared to A320? Thank you.

Monaldi Nasir (Bali, Indonesia):

Hello Randy,

Nice information about 737 max! as a passenger i like to fly with 737 ER belongs to LION air, and lion air already purchased additional 737 max aircraft couple days ago become 408 units!

Nice to fly with 737 ER and next 737 Max!

Victor Corona (Mexico City, DF.):

Hi Randy, Do you know any new designs besides engines and APU?, i mean, the doors in the 737 MAX will be open and close the same way as it is with the 737 NG?, will be bad or good that the new 737 MAX be built with sliding doors as the 777/787 and A320 family? and what advantages or disadvantages could have this modification. tnx

Mauricio Baptiste (Bogota, Colombia):

I am please to see new developments of the 737 which is the best sigle aisle jet in the market. I hope to see many 747-8i with airlines. It is a petty that AV turn to Airbus, I hope Boeing will recapture them

chltbob (Charlotte,NC):

Don't think Airbus will give up 320 and Neo sales easily. Need to take a big step and make the max into a smaller 787. Once Airbus gets their foot in the door they will more of the airlines business.The 787 technology is there. Use it!!!Glad to see the unions are on board. Their workers are going to make big bucks.

Airbus is real government sponsored competition.

Anderson Akoto (Nairobi, Kenya):

I am very exited and can't wait for the 737 MAX debut.
I just wanted to know if the 737MAX will have partial or complete fly-by-wire like the A320NEO? Also if there are going to be any changes in the cockpit layout or if its going to remain the same?
All in all I like the outside design and I hope that the 737MAX will carry on the 737's legacy of being the the most successful single-aisle twin and most popular plane.

Best of luck!

Dan Davis (Dallas, Texas):


Great job. I have one request. I've worked on 737's since 1988, PLEASE change the FWD Entry Door Torque tube design. The 50's called they want their design back. Update the door it would be a leap forward.


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