Boeing considers single, twin aisle, co-development 757/767 style for next new airplane

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Boeing is looking at a number of scenarios for its New Airplane Study (NAS) that would replace the 757 and 737, have ranges from 4,000nm-5,000nm, and carry as few passengers as 130 or as many as 240.

Leeham logo with Copyright message compactTo cover this broad range of demands could require reverting back to the 1980s when Boeing simultaneously developed two airplanes serving very different missions, the 757 and 767, that shared cockpits and some other common elements.

Boeing faces some hard decisions in the coming years, as Airbus outflanks Boeing in the single-aisle sector with the A320neo family and its latest offering, the A321neoLR. Our analysis and sales figures show the 737 MAX falling further and further behind in market share as MAX 9 lags vis-à-vis the A321neo.

We spoke with Kourosh Hadi, director of product development at Boeing, during a break at a conference last week organized by the British American Business Council-Pacific Northwest, and covered this and a number of other topics.


  • Boeing is studying a New Light Twin (NLT) and New Single Aisle (NSA) to replace the 757 and 737 airplanes.
  • The tipping point between an efficient NSA and the NLT is around the passenger size of the 757-200.
  • Boeing is evaluating materials, including metals and composites, for the NAS and the manufacturing process, which will also be a determining factor in the materials for the new airplane.
  • Engine advances for the 777X’s GE9X are beyond the GEnx and CFM LEAP of today and could help drive the next new small engine technology.
  • Although having a miniscule portion of the 100-150 seat market, Boeing today plans to continue participation in at least the 130 or 150 seat sector even as airplane size moves up every year.

The battle for dominance in the single aisle airplane sector is brutal. Boeing was the leader since the launch of the jet age, but Airbus began to pull ahead in sales during the past decade. With the launch in December 2010 of the A320neo, Airbus captured around 57% of the market in the 150-220 sector. The A321neo outsells the Boeing 737-9 MAX by a margin of two or three to one, depending on how TBD 737 sub-types are allocated in assumptions.

The proposed A321neoLR, which Airbus began showing to customers last month, equipped with three auxiliary fuel tanks and improved engines, with an EIS of 2019, is intended to replace the aging Boeing 757s used on long, thin routes across the Atlantic and in similar operations. The 737-9 can’t match the performance or specifications, which will further marginalize this sub-type and should further enhance Airbus’ growing dominance of the single-aisle market.

What’s Boeing response?

Publicly, officials remain confident the MAX family protects its market position and that Boeing will regain parity. When asked to react to the A321neoLR during his presentation at the BABC-PNW conference, Hadi expressed confidence that the 737-9 and even the 737-8 are competitive with the A321neoLR.

In our interview later in the day, Hadi described Boeing’s approach toward a 737/757 replacement, under the internal name, the New Airplane Study. Two approaches Boeing is looking at are the NSA and NLT. A twin aisle carries more weight and drag but offers quicker boarding and deplaning and more passenger comfort. But it doesn’t work well the smaller the plane and shorter the routes.

What is the cross-over point between a single-aisle and twin-aisle?

“Many elements go into that cross-over point, depending on how much comfort you put into the airplane,” Hadi told us. “The number of doors, the arrangement, the level of technology drives the different cross-overs. We know that the single aisle has limitations. You can go as high as a 757-300. The cross-over is probably somewhere around the 757-200, around 180-200 seats.”

When you look at a New Light Twin, there are two choices: 2x2x2 or a 2x3x2. A 2x3x2 is the dimension of a 767. The smaller you get, the more it looks like, and flies like a fat, little airplane. What makes more sense: a 2x2x2 or a 2x3x2?

“It all depends on what aspects the airline wants, what comfort they want,” Hadi says. “Are they significantly going to be operating shorter [routes] in terms of city pairs, or more regional routes? The door arrangements affect the definition of the airplane in terms of 2-2-2 or 2-3-2. Both of those configurations take it into another dimension and drive Business Class and First Class configurations. All of this has to be taken into account. There are many, many variables. You look at all those elements and try to get consensus among the airlines.”

While an NLT might be optimal for a United, Delta or American airlines operating it on a long, thin route, the NLT may not, and probably does not, work well for Southwest Airlines on 800 mile routes typical in the US. Additionally, the true 757 replacement market it limited. Boeing’s Randy Tinseth, VP of Marketing, previously told us there is probably a market for 1,200 757 replacement aircraft, not enough to split the market with Airbus for a new, clean sheet airplane and provide a return on the investment. This suggests that any new airplane must also cover the 737-9/A321 core market (such as US domestic service), which then would leave the 737-7/8 and A320/319neo airplanes—and these are rapidly becoming just the 737-8 and A320neo sizes.

Thus, Boeing, and Airbus, face the prospect of potentially developing an NSA and NLT sharing technology.
“That’s exactly one of the concepts we keep looking at to leverage more airplanes, more commonality,” Hadi says. “We want to emphasize commonality across our airplanes, even if they are not that close. We want to have some common features and applications from the 747 all the way to the 737. If that market, for the timing of the need for both airplanes, turns out that they could be close in terms of technology, then it could more advantage like with did with the five-seven and six-seven. A lot of things have to happen at the same time. The market space needs both of those airplanes [within a year or two] of each other. Even if it’s within five years, you can still apply technologies like you’re applying 787 technologies on the 777X.

“We start with harvesting existing technology,” Hadi continues. “We developed a lot of new technology for the 787 and we look at that as a starting point. If we need to develop beyond that, [we do]. The 777X is a great example. The 777X is a step beyond the 787 in some areas, just above the 787 technologies.”

Hadi said that high production rates of the 737 will make it challenging to transition to a replacement airplane, requiring “leaps of technologies” in many production areas. “
Manufacturing, that’s probably the biggest thing when you are trying to replace an airplane. When you are producing the airplane in the high 40s, 50s a month, you have to have leap improvements in manufacturing processes.”

Earlier in the BABC conference, a representative of the UK firm GKN pointed to the challenges of high production rates for composite airplanes. Jim Albaugh, former CEO of Boeing Commercial Airplanes, said at the time of the huge American Airlines order in July 2011 that one reason Boeing launched the MAX instead of a new, composite airplane was that Boeing couldn’t figure out to make a composite airplane at a rate of 60/mo. We asked Hadi if Boeing sees a path toward a composite airplane for a new, clean-sheet airplane in the 737 category at rate 55-60/mo, or does it have to be a metal airplane with composite wings?

“Is there a path? Yes, I would say there is a path,” Hadi says. “Is it practical at this point? I would say we have to develop the technology. We are looking at both concepts, metal and composites. I would say composites are young in its evolution, so as we evolve the materials and its production system around composites, things change rapidly. I think two years from now, five years from now, it could be a different story.”

This led to a deviation from the main topic at hand, the choice of materials for the 777X. Boeing elected to go with a metal fuselage rather than composite, and it appears most of the fuselage will be standard aluminum.

“We are still developing that,” Hadi says. “There are applications of those [aluminum-lithium] materials in some sub-components where it makes sense and cost effective in the production. At that point, there is a considerable trade [among materials]. The fuselage will be mainly today’s materials with some step-up to new alloys.”

Boeing chose to stick with a metal fuselage for several reasons.

“There were many elements involved. Time was one,” Hadi says. “We needed to get to the market. (Composites would have taken too long, it would have been an entirely new airplane.) There were benefits for composite and weight savings but it was small enough that it didn’t justify a brand new airplane. The cross section of the 777 was good enough that you didn’t have to throw that out and come up with a brand new cross section and delay the program. To accommodate that would have been small gain and benefit.”

Returning to the New Small Airplane, a lot of benefits will be driven by engine technology. The LEAP engine is probably as developed as that basic architecture can go. PW says the GTF can grow. RR is doing the UltraFan engines. We asked Hadi that if Boeing is looking at a new small airplane sometime in the second half of the 2020 decade, where do you see the engines from the three manufacturers being to provide the advances necessary to justify a clean-sheet airplane?

“The engine technology continues to evolve. The latest technology is now on the 777X (GE9X). That’s beyond the LEAP and even the 787 technology,” Hadi says. “We are in collaboration with all the engine manufacturers and we talk about the requirements needed to have the next new airplane. There’s a certain level of technology that’s beyond LEAP in the 777X that’s related to emissions, noise and fuel efficiency. You need to have a significant leap in efficiency for the lower end of the market, and when I say efficiency, I mean environment, fuel and noise.

Airbus has been quite public in saying it believes the Open Rotor will be the next leap in engine technology. Boeing’s “wise old men” consulting group, consisting of, among others, legendary designer Joe Sutter, doesn’t believe in the Open Rotor. Sutter declared in a press briefing a few years ago “there will never be an open rotor on a Boeing airplane.”

Hadi, however, says studies continue. “We are working with engine makers and regulators and depending on how regulations go, they will drive significantly ways of installing the engines and this could drive significant ways of designing the airplanes. This could take away the benefits of an open rotor.”

Noise and engine blade-out issues are major concerns around an open rotor. Some concepts include a shrouded open rotor. If Airbus believes this engine is needed for a new, highly efficient airplane, a new airplane by Boeing in 2025 may force Airbus’ hand early.

Boeing and Airbus have a miniscule participation in the 100-149 seat market. Airplane sizes are moving up. By 2025, a new airplane demand could be for the 175-225 seat market. Does this mean Boeing ceding that market to Bombardier and Embraer?

“No, not by any means,” Hadi says. “The market continues to evolve and go a little bit higher every year, but we will continue to stay engaged. Not at 100 seats, but maybe at 130 seats, 150 seats, we’ll definitely be involved.”

This clearly begs another new airplane to go that small in the 130-160 seat sector. That means a 757-767 development scenario all over again, doesn’t it?

“That’s correct,” Hadi says.

14 Comments on “Boeing considers single, twin aisle, co-development 757/767 style for next new airplane

  1. My first thought without having read the article (so with the that it might be covered in there): Won’t two airframes with as widely diverging specifications and applications as a 130-seater versus a 240-seater end up needing different wings anyway, aside from one of the airplanes having a single-aisle fuselage and the other being a twin-aisle jet?

    • I would say you would. I think you can make a new small airplane with a common base (and therefore wing) that covers a 170-230 seats segment but if you want to be competitive on the 130 seat segment your are talking a wing of around 110-120m2. The wings we looked at for 170-230 seats were around 140-150m2.

    • Ok how about a 1x1x1 Abreast in a v-shaped business class twin aisles and 1x1x1 Abreast in premium economy and a 2x2x2 Abreast in economy class for the smaller variants with 48 windows to replace the Boeing 757. And A 2x3x2 Abreast in economy class and the larger variants with 49 windows to replace the Boeing 767
      And it is closer to Boeing 787-8 Dreamliner and remember this is the opportunity for the 757/767 replacement.

  2. Hello Scott,
    Hello Bjorn

    One question, can an A321NEO LR @97 t pave the way for a “simple” re-stretch A322NEO with decent range (a little more thant current A321CEO range ?)

    • The problem for the normal A321neo is not a weight issue, it is a tank issue. You are severely fuel limited. If I enter 0 extra tanks in our model the A321neo is fuel limited from 2600nm, at that range you have used only 83t of your 93.5t of TOW with a full passenger cabin of 185 pax. So the normal 321 is fine just that the wings are too thin (read a bit old in the profile) and therefore does not hold enough fuel for longer haul. The A321neoLR does nothing to fix that.

      • Hello Bjorn,
        An A321NEO LR implies that airbus as define a landing gear able to cope with this weight, wing and fuselage structure reinforced for this weight, and so on.
        An A321 option is a 35 000 lbs engine for hot and high

        It looks like piece of a puzzle that can lead to a stretch.
        I’ve been told ( that Airbus has studied in 1990-92 a 8 and 12 frames stretch of the A321.
        Problems where : thrust (Neo got +2 000 lbs) and aerodynamic surface (flight control or flaps ? I don’t know).

        I was just saying that an A322NEO with a range equal or little more than an A321CEO can be interesting ?

        Except going with a wet tail, Airbus is stuck with ACT in the cargo hold… but it as been widely used for long on this birds (at least one or two).


      • With the A321neoLR, 2 ACTs seem to give the most benefits. 185 pax and a true 31oonm range (ESAD of 3300-3500nm) plus reserves seems doable.
        The third ACT eats into payload, for a limited range addition.

        • It all depends on your cabin’s weight, it decides if you get a fuel limited or weight limited aircraft close to max range. Two or three ACTs will vary from airline to airline, you get the most planning freedom with three if your cabin is reasonably modest in weight.

  3. Eventually Boeing has to replace the 737 with a single aisle six abreast 36m wing. Either two models 120′ and 140′ long, or three at 120′, 135′, and 150′.

    The main question is producing 50 carbon fuselage per month. How much progress has been made in answering that question since early 2011 when it was at the forefront?

  4. Hi @Scott, @Bjorn,

    It’s interesting now & again to go back & look at historical articles.

    With Airbus product line in it’s current state & Boeing in a bit of a mess, trying to work out where it should be headed, it’s informative to look at some of their past statements.

    “Hadi expressed confidence that the 737-9 and even the 737-8 are competitive with the A321neoLR”.

    @Bjorn, with what we now know about the A321NeoLR & XLR, 737-10 are you of the same opinion as you were in your comments above?

    The big question, ignoring 787 production issues, 777X delay, certification etc. What exactly should Boeing be looking at producing in the future to counter the apparent strength of the Airbus product line?

    Airbus it seems could continue to improve the A220 & introduce a -500 model, drop the A319Neo, further modify the upper end of the A320 line (A320+) & just continue with incremental improvements to all of the current range from A320 on up. Wait for newer technologies (or actually produce some kind of useful Hydrogen powered aircraft).

    Boeing looks to have a much bigger issue, is this the case? Should Boeing just wait for Airbus to move & then leap frog them?

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