After witnessing the re-engined narrowbody A320 neo (new engine option) aircraft offered by its arch-rival European aircraft manufacturer Airbus became the world’s most popular airplane in receiving 1,245 orders and commitments within a single year of the aircraft programme’s launch which landed the European Aeronautics, Defence & Space Co. (EADS) wholly-owned subsidiary a significant head-start, and announcing its re-engining decision at the eleventh hour, Chicago-based airframer Boeing last week unveiled the 737 MAX aircraft family which features maximum fuel efficiency, maximum reliability and capability that promises to help Boeing recover the sales momentum seen by its transatlantic rival (“Boeing 737 MAX press conference highlights“, 31st Aug, 11).

And the 496 orders and commitments from five airlines that Boeing received for the re-engined narrowbody which enabled Boeing to launch the 737 MAX straight away after securing the approval from its board of directors instead of the launch in fall that had been originally envisaged, are a testament that the 737 MAX will be a commercial success.

“The re-engined 737 will allow Boeing to continue to deliver the most fuel efficient, most capable airplane with the lowest operating costs in the single-aisle market. This, coupled with industry leading reliability and maintainability, is what customers have told us they want. As a result, we are seeing overwhelming demand for this new and improved version of the 737. We are working with our customers to finalise these and other agreements in the weeks and months ahead,” Boeing Commercial Airplanes (BCA) president and chief executive Jim Albaugh said.

“Customers tell us they want to improve profitability and fuel efficiency while reducing their environmental footprint. This solution meets all three of those needs.” Albuagh added.

The 737 MAX aircraft family consists of the 737 MAX 7, 737 MAX 8 and 737 MAX 9 variants, the re-engined versions of the 737-700, 737-800 and 737-900ER (extended range) in the existing 737 NG (Next-Generation) family, respectively.

Image Courtesy of Boeing

The Boeing 737 MAX will be equipped with CFM International Leap-1B engine and will be 10-12% more fuel efficient than the existing 737 NG, thereby enabling it to be 16% more fuel efficient than the existing A320 as well as 4% more fuel efficient than the A320 neo on a per seat basis, Boeing said.

“The 737 MAX fuel efficiency improvement over the Next-Generation will be 10-12%, we already offer winglets on the plane that we have for the past 10 years, and the fuel burn will be 4% better per seat than the competition,” Boeing Commercial Airplanes (BCA) vice president (VP) for business development and strategic integration Nicole Piasecki confirmed.

“The 737 Next-Generation today is significantly more reliable than our competition in the A320. Today 99.7% of the next-generation 737s are ready to take off within 15 minutes of their schedules. There can only be one leader and this is the MAX in terms of capability, efficiency and reliability,” Piasecki conceded.

The contentious fuel burn debate
Meanwhile, despite some sceptics have questioned with a 10-12% fuel burn improvement whether the 737 MAX will burn more fuel than the A320 neo whose advertised fuel burn saving is 15%, there is indeed some merit to Boeing’s claim in a lower fuel burn, particularly on the shorter sector, as well as having a lower operating cost than the A320 neo, with an AirInsight article putting the 737 MAX as having a 2% lower operating cost per hour than the A320 neo.

Boeing’s fuel burn comparison between the 737 MAX 8 and the A320 neo assumes a mission stage length of 500 nautical miles (nm) and the 737 MAX 8 in a 162-seat configuration against the A320 neo in a 150-seat configuration.

Interestingly, Aspire Aviation understands that the existing Airbus offerings do have a lower fuel burn than their Boeing counterparts on a longer sector but a higher fuel burn than Boeing’s on a shorter sector, with the A321 burning up to 4% less fuel than a 737-900ER in a longer segment. For instance, in the race for a 757 replacement, Boeing claims a 180-seat Boeing 737-900ER burns 11.3% less fuel than the 183-seat A321 in trip fuel and 9.5% less fuel on a seat-mile fuel basis whereas Airbus counters by saying its 185-seat A321 neo is 20% better than a 173-seat Boeing 737-900ER on a seat-mile basis and 14% better on an airplane mile basis over an 800 nm segment, an AirInsight report titled “Comparing 757 Replacements” says.

However, two of Aspire Aviation‘s sources at the Chicago-based airframer cautioned that the 10-12% fuel burn saving figure Boeing provided is “preliminary” and does not take into account any fuel burn saving brought by the aerodynamic changes and weight savings that the world’s second-largest aircraft manufacturer is currently studying or going to be featured.

These aerodynamic changes and weight saving endeavours, the same Boeing sources claim, would be sufficient to ultimately enable the 737 MAX to be 15% more fuel efficient than the 737 NG (Next-Generation).

With the 737 MAX configuration going to be finalised in late September, Boeing is expected to provide more clarity on the aircraft’s configuration in its 2011 third-quarter earnings conference call, Aspire Aviation has learned.

Engine fan size decision
Owing to the limitation of the 737 NG (Next-Generation)’s ground clearance which enables a faster turnaround time yet poses a challenge on the engine fan size decision when re-engining the 737 NG, Boeing has now narrowed to two options in either a 66 inches fan or 68 inches fan.

“The engine that we are going to put on would be a Leap engine from CFM, right now we are looking at 2 different sizes: the 68 and the 66-inch fan blade. In either case we remain very confident that this is not going to require a lot of modifications to the gear; certainly with the 66 [inches fan size] no modification; and even with the 68 [inches fan size] a very low probability to have to touch the front gear,” Boeing Commercial Airplanes (BCA) chief executive Jim Albaugh reiterated.

“What we try to do with our decision on the engine is to maximise what this airplane can do, with a bigger, you get more efficiency because of the bypass ratio but what you will find with a bigger fan is you get more weight and you get more drag,” Albaugh explained.

“There are some advantages in the 66 [inches fan size] that we like and there are some advantages in the 68 [inches fan size] that we like and we are doing the final trades right now and we will make the decision in the next several weeks,” Albaugh asserted.

While the 66-inch fan size would not require a lengthening of the 737 NG’s nose landing gear, thereby minimising any modifications involved in the re-engining programme and comfortably leaving the 737 MAX 17 inches above the ground, a smaller engine fan would generally imply a 0.5% higher fuel burn for every inch in a decrease in the engine’s fan size.

However, Aspire Aviation‘s source at the world’s second-largest aircraft manufacturer says there are “plenty of options” on which the design of the CFM Leap-1B engine could be optimised and still deliver a previously reported 13%-14% fuel burn saving for a 66-inch engine fan that would deliver a 10-12% fuel burn saving after shaving a few percentage points of fuel burn saving off caused by the weight penalty involved in strengthening the centre wing box when integrating a heavier engine onto the airframe. These sources also clarify that the fuel burn calculation is not linear and hence the possibility of optimising the engine design yet delivering the same fuel burn saving cannot be discounted, after factoring in the lower weight and drag of a smaller fan size engine.

Separately, these sources confirm that the 66-inch engine fan size option remains the most preferred solution.

Image Courtesy of Boeing

Limiting work scope with significant advancements
Still reeling from the impacts brought by the perennial Boeing 787 Dreamliner and 747-8 programmes delays, which resulted in a 3-year and 2-year postponement in the aircraft’s respective entries into service (EIS) and significant cost overruns that pushed the latest refresh of the iconic 747 programme into a forward-loss position, Boeing has been conservative in not only the 10%-12% fuel burn saving figure it touted, but also the 737 MAX’s entry into service (EIS) in 2017.

Boeing intends to bring the 2017 EIS date of the 737 MAX forward, Leeham News reported.

“Given our recent track record, we are being very conservative – not conservative, we are being very prudent, I should say – and disciplined to make sure that whatever we talk to our customers about, we actually have a plan to deliver on. I think you will see improvements on the 2017 [EIS target], but again our team is very disciplined and we are going to make sure we have a plan before we make a commitment,” Boeing Commercial Airplanes (BCA) vice president (VP) in business development and strategic integration Nicole Piasecki said.

But an earlier entry into service (EIS) target would be contingent upon the success of Boeing in limiting the work scope while bringing significant advancements at the same time.

For example, the 737 MAX features a straightened vertical stabiliser, a 787-styled tail cone with a light-emitting diode (LED) auxiliary power unit (APU) light as well as a modified wing fairing and an elimination of the aft-fuselage joint in the official Boeing renderings. Other options being studied include a simplification in flap settings and a 777-styled raked wingtip, Aspire Aviation has learned.

While the 777-styled raked wingtip being studied is similar to the one featured on the US Navy’s P-8A Poseidon anti-submarine and reconnaissance aircraft, Aspire Aviation‘s source believes the raked wingtip is unlikely to find its way onto the re-engined 737 MAX aircraft, citing different mission profiles between the defence and commercial use of the aircraft.

“There are lots of things we could do with this airplane, but what we want to do is to limit the scope of work and we are going to limit the scope of work to things associated with the engines,” Boeing Commercial Airplanes (BCA) chief executive Jim Albaugh asserted.

“We are going to make this the simplest re-engine possible. We are only going to touch parts of the airplane impacted by the engine and a couple of other clean-ups,” Albaugh emphasised.

Surprisingly, Boeing Commercial Airplanes (BCA) Jim Albaugh revealed that “some fly-by-wire” elements will be featured on the 737 MAX, which Aspire Aviation‘s source says will save significant weight through alleviating loads on the outer wing and shifting parts of those loads inwards or even to the centre wing box.

“There are a couple of things more fly-by-wire, but very minimal things, very minimal,” Albaugh stressed.

Initial indications point to the use of fly-by-wire technology on the 737 MAX’s ailerons and spoilers, which would achieve the aforementioned benefits of alleviating and shifting loads. Given this would be similar to the 747-8’s partial fly-by-wire system, coupled with the naming of Michael Teal as the 737 MAX’s vice president (VP), chief project engineer and deputy programme manager who has just worked as the new jumbo’s chief project engineer, significant insights and invaluable experience could be shared on the fly-by-wire system introduction on the 737 MAX.

“What we are trying to do is to optimise the design of the airplane and integrate the design of the airplane,” Albaugh elaborated.

Image Courtesy of Boeing

Notwithstanding these aerodynamic changes and the introduction of a partial fly-by-wire system would undoubtedly make the 737 MAX considerably more competitive, these modifications would also necessitate a US Federal Aviation Administration (FAA) recertification and could swell the re-engining programme’s research and development (R&D) costs. Aspire Aviation also questions whether the scope of the FAA recertification would be limited to the engine alone as Boeing Commercial Airplanes (BCA) chief executive Jim Albaugh conceded.

“Recertification, obviously, those are some questions we have to work with the FAA our expectation is there will be a certification issue that has to do with the re-engine [but] nothing more,” Albaugh commented.

Analysts have put the cost of re-certifying the 737 MAX at as high as US$1 billion and the overall programme cost at US$1-2 billion in average. With these modifications which Aspire Aviation thinks constitute significant advancements, the programme cost could potentially top US$3 billion.

Make no mistake, Aspire Aviation is generally positive on these aerodynamic changes and the introduction of fly-by-wire system on the 737 MAX, as they improve fuel burn and reduce weight beyond the 10%-12% fuel burn saving touted by Boeing which makes the 737 MAX much more competitive and improves its sales prospect in the future when it faces a stiff competition with Airbus’ A320 neo (new engine option).

Coupled with the anticipated steady decline in research and development (R&D) expense over the course of the next few years in light of the 787 and 747-8’s entries into service (EIS), Aspire Aviation does not think expected R&D holiday to be substantially impacted by the 737 MAX, even with a 787-10X launch in 2012, as the double-stretch 787 variant would require minimal engineering resources whose foundations of the stretching work have already been laid by the 787-9 variant.

Furthermore, Boeing seems to be deliberately conservative in light of the recent troubles plaguing its aircraft development programmes.

“One of the things we’ve learned on the 747-8 and the 787 programmes is you want to make sure that any date we quote is a date we can meet,” Boeing Commercial Airplanes (BCA) president and chief executive Jim Albaugh acknowledged.

“And I’d rather under-promise than over-promise and we think we have the right amount of contingency in this programme and so I’m very comfortable with the commitment we’ve made, to deliver this airplane by 2017.

“Managing this programme can be a task in itself, and while this is a very low-risk approach to what we’re going to do with this airplane, this has to be managed very, very well and has to take into account all the lessons learned from all the programmes we have done before,” Albaugh admitted.

In the meantime, Boeing has decided not to put a 787-styled cockpit which the company once considered on the 737 MAX in order to preserve the commonality with the existing 737 NG (Next-Generation), which could also simplify the FAA recertification efforts.

“On the cockpit, some people might say the cockpit is an old one to us a state-of-the-art from a navigation standpoint and from a flight control standpoint, we think it is what the customers want,” Boeing Commercial Airplanes (BCA) chief executive Jim Albaugh commented.

“One of the things that we do want to make sure we have with this airplane is compatibility with NG, compatibility with airplanes we’ve already delivered and what our customers have told us is don’t touch the cockpit and our plan is not to do that,” Albaugh said.

Conclusion
The business case of the 737 MAX remains exceptionally strong despite Boeing’s comparatively late decision to go down the re-engining route, with a significant Southwest Airlines order in the making along with numerous negotiations with other carriers. Aspire Aviation understands that Canada’s WestJet and the Irish low-cost carrier (LCC) Ryanair have been in contact with Boeing though the state of their negotiations or the timing of any aircraft orders are not immediately clear as of this writing.

Moreover, the aerodynamic changes and the introduction of partial fly-by-wire system as well as a laminar flow system on its vertical stabilisers are going to make the 737 MAX even more competitive with its fuel burn potentially being 15% lower than the existing 737 NG, matching Airbus A320 neo’s advertised 15% fuel burn reduction and exceeding the latter’s fuel burn when considering the fuel burn advantage that the 737 NG retains today.

Image Courtesy of Boeing

What is more, the partial fly-by-wire system not only alleviates and shifts loads inwards thereby saving a significant amount of weight, the redistribution of loads could also enable Boeing to increase the maximum take-off weight (MTOW) of each 737 MAX variant, which would enable the 737 MAX to carry more payload when compared to the existing 737 NG with the same range.

This could be particularly attractive on the 737 MAX 9 which will position Boeing well against the competing Airbus A321 neo (new engine option) in vying for 757 replacement orders.

In doing so, the increased MTOW of the 737 MAX 9 would potentially make it more of a true 757 replacement than the A321 neo is, should Boeing opt to go forward with the concept of an increased MTOW.

“The 737 MAX 9 [has] about 5% better operating economics for its seat-mile economics and its trip costs will be about 6% better [than the A321 neo]. Its operating economics are significantly better,” Boeing Commercial Airplanes (BCA) vice president (VP) in business development and strategic integration Nicole Piasecki told Commercial Aviation Online.

“We are currently working on its range capabilities with customers right now. We have a lot of range in the 737NG and we have to make sure are there missions out there that our customers want more range capability so we can be sure to capture the 757 market,” Piasecki added.

Last but not least, as the detailed configuration of the 737 MAX is still being finalised, a point that is sure is Boeing 737 MAX will unquestionably be a commercial success, with Boeing very likely to maintain its existing market share on the 737 NG (Next-Generation). But given its recent track record on the 787 and 747-8 programmes, Boeing can ill-afford to fail to deliver on its promises on the 737 MAX. For the time being, black eyes will continue to monitor on Boeing’s progress on the 787 production ramp-up, the 787-9 development and the 737 MAX and that execution will remain as the biggest challenge facing the world’s largest aerospace company.

Read the excerpt of key quotes Boeing executives made on the 737 MAX press conference >>

11 Comments

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  • le bon vivant 2011 Sep 06 / 14:59

    I think the top management and the board of directors at Boeing are smoking something that inhibit their thinking abilities. Not long ago they said that there was no business case for a 737 NEO and that their customers were pushing for a new aircraft. That is the very thinking that took them to the Paris airshow with NOTHING

  • le bon vivant 2011 Sep 06 / 15:26

    I think the top management and the board of directors at Boeing are smoking something that inhibit their thinking abilities. Not long ago they said that there was no business case for a 737 NEO and that their customers were pushing for a new aircraft. That is the very thinking that took them to the Paris airshow with NOTHING to offer. They sat and watched airbus making them look stupid.
    The EIS date seem to bee too far, if they launch the MAX now and EIS is only in 2017, that means 6 years later and 2 years later than the A32 neo. They have to take a closer look and do better than that.
    However, given that only 5 airlines have ordered 490 aircrafts, it looks like the number will go up even higher than the airbus neo as more customers are coming on boards. Until they rack up the orders, boing still looks silly for letting airbus take the lead.

  • keesje 2011 Sep 06 / 19:29

    “a smaller engine fan would generally imply a 0.5% higher fuel burn for every inch in a decrease in the engine’s fan size.

    If we translate this rule of thumb comparing a LEAP powered 737-9 with a LEAP powered A321NEO that would assume the NEO has a 5% better sfc. (assuming a 68 inch fan for the MAX and an 78 inch for the NEO.

    Furthermore it is sensible to assume Airbus didn’t put back the A321 NEO 2 yrs without a reason, while keeping the A320 NEO schedule as is. Most likely their will be enhancements focussed on payload range.
    .

  • Daniel Tsang 2011 Sep 06 / 23:31

    keesje,

    Your calculation is inaccurate.

    As I wrote, “These sources also clarify that the fuel burn calculation is not linear and hence the possibility of optimising the engine design yet delivering the same fuel burn saving cannot be discounted, after factoring in the lower weight and drag of a smaller fan size engine.”

    The 737-900ER is 5% lighter per seat than the A321 Classic & the 737 MAX 9 will also be lighter than the A321 neo due to the smaller & lighter LEAP engine, therefore Boeing could claim the 737 MAX 9 being more fuel efficient than the A321 neo on a per seat basis.

    Payload/range improvements on the A321 neo? At least that is not on Airbus’ card for now, keesje.

    Airbus would want to limit changes to bring as much fuel efficiency as fast as possible from October 2015. If Airbus intends to introduce payload/range improvement on the A321 neo, a 2015 EIS schedule would be demanding from an engineering resource perspective, owing to the A350-900, -1000 & -800, whose official EIS target is 2nd half of 2013, 2017 & 2016, respectively.

    But Boeing will have to rely on challenging significant advancements – partial FBW & aerodynamic changes to increase MTOW of the 737 MAX 9 in addition to possibly matching a 15% fuel burn reduction on the A321 neo.

  • keesje 2011 Sep 11 / 23:10

    “If Airbus intends to introduce payload/range improvement on the A321 neo, a 2015 EIS schedule would be demanding from an engineering resource perspective”

    Indeed Daniel, but the A321 NEO will EIS in 2017.

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