But what of the runway performance?

Dominic Gates of The Seattle Times has this story in which he has the following observation:

Wyse revealed that Boeing, through structural efficiencies, has also beefed up the allowed maximum take-off weights for the three MAX variants.

Each is 5,000 to 7,000 lbs heavier than the maximum take-off weights of the current 737s.

That means each 737 MAX model, even though heavier than the corresponding current model of the 737NG, can either carry a heavier payload or carry more fuel and so fly farther.

This is good. But we’re hearing from airlines that runway performance may be worse than the 737NG. The airplane is heavier but the wing is the same and the engine thrust is still somewhat of a mystery. CFM International, maker of the LEAP-1B that will power the MAX, lists thrust on its website of 20,000-28,000 lbs without identifying the sub-types and thrust to which the engines will be applied.

These thrust ratings are similar to those now on the NG, rather than being increased to compensate for the increased weight.

One airline tells us that runway performance for the -8 MAX and -9 MAX is longer than the -800 and -900. (The airline is not considering the -7 MAX and doesn’t have the -700.) This, the airline tells us, makes the airplanes problematic at some airports it serves.

This illustrates the dilemma Boeing and CFM have with the physically-constrained 737. CFM could build any engine it wants that would get the job done. It has, after all, two LEAP engines in development for the COMAC C919 and the Airbus A320neo. But the 737 presents special challenges and CFM is constrained unless Boeing lifts the entire airplane with new main gear. But this would mean a new wing box and associated structural changes, adding significantly to the cost. And Boeing won’t to this.

There’s still a lot about MAX we don’t know. And many customers are also waiting for the information.

39 Comments on “But what of the runway performance?

  1. Scott: Re: “There’s still a lot about MAX we don’t know. And many customers are
    also waiting for the information.”

    We are now almost exactly a full year after the MAX was given a chance to prove
    itself, when AA gave Boeing a “commitment” for 100 units, based on the condition
    that Boeing would provide AA with the necessary Spec./operating cots etc. by Nov.
    LAST year! No word from AA or Boeing on that commitment!

    No wander your quote above, is the reason for the lack of many orders at the FAS
    this year and hopefully not a sign for the future of the MAX!
    But, I am holding my breath! Inaptitude, inexperience and bad Management?

    The appointment of Ray Conner, as CEO of Boeing Commercial Airplanes, clearly
    didn’t come a day to soon!

  2. The GECAS announcement was an MoU, not a formal order. Is that significant?

    • NOT even sure it rose to the level of an MOU; Boeing used “commitment” in the press release. GECAS was one of the Unidentifieds in the +1,000 commitments talked about since last year. So GECAS isn’t a new customer and this isn’t an order. It’s just a public announcement of what the industry has known for eight or nine months.

  3. Just now, only the faith in Boeing and CFM/GE may save the impulse of the MAX customers …. since the facts are not all together today !
    And with all the discounts included, it’s a very big, 20 billion + $ act of faith …
    Going to duplicate at the end of this year !
    May be it works, Boeing and GE have the strength and the money to make it true !
    May be not so sure in … 2017 … but like the B787, at the end, they will make it !

    And … NSA speaking …
    I just think , than with the same type of engines, the NSA case was lost for 2020-22 !
    15% improvements for the plane were necessary to launch the project …
    A new Boeing NSA, may get a 6-8% bonus in the best cases for his hull and his wings … Airbus may contest with Al-Li and / or CFRP wings, the CS-100 way, reducing the advantage to the Half !

    Open Rotors Engines may give à 25 % advantage in 2025, over the current NG engines, they are projects with a lot of constraints, and unknown’s, while the best new engines (GTF type) may well be above the 20% gains for the same time slot !
    I understand perfectly Boeing think it twice, before venturing in the NSA project !

  4. This take is interesting ; South west has ordered Max – and are one of the biggest operators at Midway , Chicago , a small airport ,with constrained runways . I would not start a A v B discussion here , but I remember reading that Southwest specifically saying, they decided on Max esp considering Midway’s runways.
    We may say a lot about Boeing’s decision making on NSA vs Max, delay now acknowledged Jim M et al ; unless we know more about the engine thrust details, let us not run ahead of ourselves ; not that it is not a valid point.
    737 is known for short take offs and landing ; I cannot believe that they will give that product capability up in upgrading the engines. for Max .

  5. It is not only engine performance, it is L/D ie drag vs thrust. The new split winglet will buy the MAX some runway performance as induced drag is some 80% of the start drag. Question is if the reduced drag and Leap thrust can keep the performance where it should be.

  6. Didn’t they say several times that the firm configuration will only be achieved in late 2013?

    They are not in hurry.

  7. Rensim
    “Maybe it works, Boeing and GE have the strength and the money to make it true!
    May be not so sure in … 2017 … but like the B787, at the end, they will make it!”
    That appears to be a contradiction in terms, because they DO NOT “have the
    money to make it true” and especially NOT LIKE THE 787, which IN THE END
    chalk up $35 Billion in development costs, which they may never earn back!
    That IS clearly NOT the way “they will (or should) make it” with the MAX in the end.

  8. With a combination of thrust, carbon brakes, new winglet, revised spoilers and efficiency improvements to the high-lift devices, the 737 MAX has equal or better field performance than the NG. It’s a valid technical consideration of the added operating weights, but it is something which has already been solved.

    • How do carbon brakes and revised spoilers help take-off performance? Is there some new innovation here that I’m unaware of?

  9. If a -800 and a MAX 8 lift an equal load, which will have better field performance?

    • That depends on the changes made to the -8MAX. Could be better, could be worse. Heavier weights, with no other changes, would naturally give worse performance. This can be mitigated by changes in the wings, brakes, Thrust Reversers, etc.

  10. Comment is here as it concerns the overall performance figures for the MAX, even though it touches on the MAX sales campaign.

    The fact that GECAS has still not signed a firm order for the MAX has got to be very damaging to the MAX program. That they were not amongst the first to do so, certainly did not help and even were they to sign it before the end of the airshow, much of this damage has already been done.
    The question is, how much of the damage can and will be undone when they finally do sign?

  11. vaidya sethuraman :
    This take is interesting ; South west has ordered Max – and are one of the biggest operators at Midway , Chicago , a small airport ,with constrained runways . I would not start a A v B discussion here , but I remember reading that Southwest specifically saying, they decided on Max esp considering Midway’s runways.

    Depends. The runway perf is an issue when close to MTOW, implying flying the full capable distance. Otherwise, it has a limited impact.

    To confirm if Midway is an issue, you should look at the routes from there, and they aren’t that long.

  12. keesje :
    The real question behind this all is if the 737-9 MAX is the best 757 replacement as this gentleman is pressing.
    And if UA and DL agree.

    UA and DL have already spoken with their pocketbooks. DL just bought 100 737-900ER & United already operates many 737-900ERs with another 40 or so on order. It appears we will learn tomorrow if UA has bought MAX version for 757 replacement, but all rumors would indicate this is the case. Neither DL or UA operate or have ordered any version of the A321, primarily because it cannot do US transcon, which is a critical mission for both operators. Are you really still wondering if Delta and United believe in the 737-900ER / 737-9???

    • Yes, based on their network requirements and 737-900ER and -9 runway performance.

      AA also ordered 100 737 MAX aircraft. But not to replace 757s and 762s into the Caribbean.

      Check my reply at #7 to see what pilots think about it, and
      http://www.airlinepilotforums.com/archive/index.php/t-59113.html

      The 739ER having no issues transcon is a feel good story. West bound in the winter is an issue. Flights have scheduled fuel stops.

      IMO opinion DL and UA need / want A321NEO, however those are far away and Leahy is probably stiff on discounts because he knows his position.

      Not to say DL/ NWAC didn’t fix another smart fleet move with the 737-900ER order, very efficient aircraft, probably at a moment Boeing was very willing to give discounts and early slots. It will replace 757 and offer efficient growth on almost all US routes. I respect DL (NWAC) fleet strategy. Unconventional, value based, opportunistic.

      • The A321 has the same size wing as the 737. Neither will provide optimum efficiency at greater payloads. A bigger wing on a new aircraft is needed. When it is built, it will create its own market. Who will seize the opportunity, Boeing or Airbus?

  13. “They are not in a hurry.”

    Problem is, they need to be. There seems to be a decided lack of urgency from Boeing lately regarding specificity on new models. Firming up the MAX configuration is just one element of a list that also prominently includes beating around the bush with the 787-10X and 777X launches. Boeing needs to realize that in every segment except the currently-launched 787 variants, they are lagging behind Airbus on the timeline for development and EIS. This means the burden is on them to firm up and develop their new models as quickly as possible, so customers have a chance to make full comparisons and order before they get tired of waiting and just go with what’s already available.

    Boeing needs to get the MAX firmed fast so they can start getting more orders instead of committments. They need to launch the 787-10 before Airbus can eliminate any question marks with the A359-900. And they REALLY need to get moving and launch the 777x before anyone else follows Cathay’s example.

    • Brian,

      Neither Boeing nor Airbus is well served by racing forward with… with what? That is the problem. When you rush out with a “firm” specification before you are ready, you get the debacle of the A350-1000, which Airbus has been living with for the past 4 years. To be honest, Boeing was probably ahead of themselves a year ago announcing the MAX. Firm configuration is next year, which will satisfy most of the operators who are waiting for more concrete details about the airplane. Simply fabricating those details which don’t exist today in order to make sales is not the right way to do business. The same is true for the 787-10X and the 777X. There’s a process to be followed, and Boeing is working through the requisite developmental gates in a systematic manner for all three PD models.

      As for “lagging behind” on orders, it’s not really the case at all. If you take a look at the delivery skyline for the A320neo, 737 MAX, 787 and A350, all of these models are essentially sold out to the same point in the future (around 2019). Operators are very reluctant to place orders for aircraft further out than this due to uncertainties about the economy that far out, as well as the effect on price escalations they will incur on their aircraft over the next 7 years. The panic/rejoicing (depending on your bias) over “lagging” 737 MAX orders is fun for bloggers and fanboys, but is entirely misguided. Both aircraft will sell at virtual parity for the next decade. Whatever differences exist in performance and economics between the two will be addressed in pricing, as has been the case for the past 15 years. Nothing will change, except that the CSeries seems poised to steal some bottom end of the market from both OEMs.

      CM

  14. CM’s comments somewhat reflect industry reality, I fail to see the media panic or rejoicing he describes.

    It is interesting to look at hard & fast numbers, the MAX in almost at the point now when the NEO entered it’s order frenzy. In terms of engineering the 320 appears a more effective reworking project, meanwhile the apparent sales lag of the MAX is perhaps caused because the industry see’s it as mutton dressed as lamb.

  15. CM Of course you have to inform yourself before you take decisions. But that doesn’t justify beeing one step behind all the time.

    Albaugh did just that a year ago. Sticking to the strategy, looking at all options, talking to all the customers and being mercely bypassed at the same time. A month later was AA order signing.

    http://www.youtube.com/watch?v=rJzRsodeYes

  16. CM, you are misquoting me. I did not say Boeing was lagging behind in orders, I said they are lagging behind on the TIMELINE. This is undeniably true in every segment except the 787-8/9 (2017 EIS for the MAX vs. 2015 for the neo, ~2019 for the 787-10 and 777x vs. 2014-5 for the A350-900 and 2017-8 for the -1000). While one can argue that an extra couple of years to get the better product will win out in the long run, I still think it’s important to at least get the designs to an offerable/orderable state in a timely manner. This is especially true for the narrowbody market, where operators are far more likely to stick exclusively with one manufacturer/aircraft family on each generation of aircraft, and where the aircraft offerings are far more similar. So here, early orders are key, and it’s the early bird that gets them.

    Of course no company wants to rush out a design that isn’t ready, and then have to keep changing it during development. My point is Boeing needs to be working harder to get the designs ready. They already got themselves in a hole by being late to the re-engining party; they can’t afford to fall any further behind. I agree the narrowbody market should balance out near parity, but Boeing’s actions now will determine how close to parity it gets.

    • Lagging on the 777x??? LOL, you seem to forget the A350 was a slapdash response to the 787, which had to be replaced with the A350XWB, which is still a response to 787 and success of the 777-300ER.

      I always find it amusing that half a dozen years can make people forget the facts of history.

  17. Brian :
    CM, you are misquoting me. I did not say Boeing was lagging behind in orders, I said they are lagging behind on the TIMELINE.

    But you are talking about orders, Brian. You went on to say…

    Brian :
    This means the burden is on them to firm up and develop their new models as quickly as possible, so customers have a chance to make full comparisons and order before they get tired of waiting and just go with what’s already available.

    and…

    Brian :
    Boeing needs to get the MAX firmed fast so they can start getting more orders instead of committments.

    …but that’s OK. At the end of the day, orders (market share) are one of the key measures of success in this business, so it’s definitely something to worry about. My only points were this:

    1. You cannot short circuit the product development process without bringing avoidable grief upon yourself.

    and

    2. The skyline for all of the products you mention are very full, out to the point where it is very difficult to get additional firm orders.

    • CM,
      I am a bit confused.

      Airbus has 1520 firm orders for the NEO and plans to start delivering in 2015 Q3 (October).

      Boeing has 549 firm orders for the MAX and plans to start delivering in 2017, possibly earlier.

      You state that both NEO and MAX are sold out until about 2019.

      Does this mean that Boeing has a slower delivery rate planned for the MAX than Airbus has for the NEO?

      • Hi A.N.

        Both 737 MAX and A320neo production are essentially sold out through 2019.

        Both companies will manufacture roughly the same number of 737 and A320 frames (all minor models) between now and 2019. However, the ramp up is not linear for the A320neo nor the MAX. As a result, the earlier start for the A320neo skews the in-service fleet numbers at 2019 heavily in favor of the A230neo. That difference basically accounts for the current order disparity between the neo and the MAX.

        People are wondering why operators are not firming orders for the MAX to the same numbers they did for the neo and wondering if its because there is something wrong with the 737 MAX. There’s not. The reason for the reluctance to firm orders is in part due to Boeing only now firming up the performance specification of the MAX. The other major reason has to do with how far out the availability of MAX frames is.

        I think Boeing may be able to get MAX orders up to around 800 or 1000, after which I will not be surprised to see orders stall to something close to the production rate, much as we have seen over the past few years for the 787 and A350. Neither OEM has much luck signing new customers for aircraft which do not deliver for nearly a decade. The price escalation clauses become too large of a factor and the airlines are essentially forced to speculate on a market so far out they cannot predict it.

        Sorry if that’s not a very well written explanation. Let me know if I’m still not being clear.

      • Your NEO count is a bit off. Airbus has, per Bregier today, 1454 orders and commitments.

      • 2years is about 1000 narrowbodies with raised production rates. Under the assumption that airllines don’t order beyond
        a 7 year horizon MAX firm orders will now only slowly rise further.

  18. CM :
    With a combination of thrust, carbon brakes, new winglet, revised spoilers and efficiency improvements to the high-lift devices, the 737 MAX has equal or better field performance than the NG. It’s a valid technical consideration of the added operating weights, but it is something which has already been solved.

    And this should be taken at a face value but we should dismiss the A3510 fuel burn because you say so. Talk about double standards.

    • I assume you are talking about comments on airliners.net? Like my comments about the 737 MAX field performance, my comments on why the A350-1000 will struggle to meet Airbus public fuel burn numbers were provided with the technical reasons which lead me to feel that way. I wouldn’t expect you to take my word for anything. Consider the reasons I offered and make your own informed decision.

      MAX operating weight increase impact on field performance is mitigated by…

      -A winglet which increases L/D of the wing
      -Performance credit being taken for carbon brakes
      -New scheduling of the spoilers via FBW
      -High-lift device efficiency improvements

      A350-1000 fuel burn will be degraded relative to the original A350-1000 specification because airbus has been forced to…

      -Increase the operating weight of the airplane
      -Increase the thrust of the engine via a larger core while constraining fan diameter. In other words, they have reduced the bypass ratio of the engine.
      -Increase the area of the wing via a trailing edge extension. This increases wetted area and drag disproportionately for the lift gained It reduces aspect ratio of the wing and degrades L/D. In other words, the wing has become less efficient.

      The general consensus is these changes resulted in a 3% penalty to A350-1000 fuel burn. You don’t have to take my word for it. There are numerous comments from TIm Clark, Al Bakar and Steve Hazy lamenting these changes and the loss of efficiency relative to the original A350-1000 spec.

      • -“Increase the thrust of the engine via a larger core while constraining fan diameter. In other words, they have reduced the bypass ratio of the engine.”

        But bypass ratio is not the only metric of importance, is it?

        According to RR, the Trent XWB-97 will be incorporating some “clever” modifications inside the engine; thus RR expect to see no increase in TSFC in the XWB-97 relative to the XWB-84. For example, the angular speed of the LP spool will increase by 6 percent while the core will be slightly larger in size.

        In comparison, GE reduced the bypass ratio of the GE90-115B to just over 7, from around 8.5 on the GE90-94B while increasing the fan diameter by 5 percent. The maximum angular speed of the low-pressure spool was increased by 5.5 percent over the base engine, and the maximum generated torque of the LPT was increased by 31 percent. Overall pressure ratio at maximum power is 40 for the -94B and 42 for the -115B. Interestingly, it doesn’t look like the TSFC of the -115B suffered notably because of these enhancements in comparison to the TSFC on the -94B.

        -“Increase the area of the wing via a trailing edge extension. This increases wetted area and drag disproportionately for the lift gained It reduces aspect ratio of the wing and degrades L/D. In other words, the wing has become less efficient”

        Are you sure about that?

        The trailing edge extension allows for an increase in lift-over-drag in take-off thus enabling steeper climb and reducing noise footprint. Hence increased climb performance offsets increased drag.

        http://www.flightglobal.com/news/articles/airbus-opts-for-larger-wing-on-a350-1000-through-trailing-edge-341004/

        Airbus’s operational requirement targets for the -1000 include keeping the approach speed to 150kt (277km/h) at maximum landing weight, compliance with London’s QC1 noise requirements for arrival and QC2 for departures, and the capability to reach an initial cruise altitude of 33,000ft (10,000m) in less than 30min.

        “With these parameters we were able to do the work to design the wing, and we found that with some changes to the trailing edge we can meet all these requirements,” says McConnell.

        The wing will feature a trailing-edge extension increasing its area by 4%, which McConnell describes as “quite a big change because it extends the high-lift devices and the ailerons, making the chord bigger by around 400mm. We’ve been able to optimise the flap lift performance as well as gain more performance in the cruise.”

      • Addendum:

        In comparison, GE reduced the bypass ratio of the GE90-115B to just over 7, from around 8.5 on the GE90-94B while increasing the fan diameter by 5 inches. 🙂

  19. That’s perfectly true, Howard: it did take Airbus a long time and multiple tries before they settled on an A350 that customers wanted. So that did leave Airbus lagging behind. The old Boeing timeline (787 EIS in 2008) would have been fabulous for them, keeping them ahead of the comparable Airbus projects with the 787-10, NSA, and 777 upgrade/replacement. But all the 787 delays negated Airbus’ issues getting the A350 desin together, and pushed back Boeing’s timeline, so now they’re a couple steps behind.

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