Engine OEMs diverge on technology for next generation

March 7, 2017, © Leeham Co.: Representatives of the four major commercial engine

GE9X, the final engine in a decade-long engine renewal program for GE Aviation and CFM International

manufacturers have divergent views of the next round of engine development, either for the Middle of the Market/New Mid-range Airplane (NMA) or New Small Airplanes (NSA) coming in the next decade.

Officials of CFM, GE, Pratt & Whitney and Rolls-Royce appeared at the annual ISTAT conference in San Diego yesterday.

PW’s Rick Deurloo, SVP of Sales, Marketing Commercial Engines, had the added task of dealing with the highly-publicized teething issues surrounding its new Geared Turbo Fan engine on the Airbus A320neo.

Next generation engines

GE Aviation’s Bill Brown, Commercial Engines Managing Director, said GE and CFM International, in which GE and France’s Safran are joint partners, are completing a decade-long plan to renew their entire engine lines that encompass turbo-props to the giant GE9X being developed for the Boeing 777X.

The industry is already talking about new engines for the NMA and NSA aircraft. Program launch, if it comes, for the NMA is widely believed to be next year for a 2024-25 entry-into-service. Program launch for the NSA is more nebulous, varying from as early as 2020 (for Boeing) to as late as 2023 (for Boeing and Airbus.) EIS would be about seven years later.

Both airplanes depend on new engines, a next generation design that would offer at least 15% and as much as 25% better fuel economy than the LEAP and neo engines now entering service.

Brown, who for many years was assigned to CFM, cautioned that any new design and architecture for the engines depends on the airframe architecture.

Proceeding with a new engine architecture before knowing the airframe “is an ill-conceived idea,” he said. Open rotors and GTF technologies are among those GE and CFM are known to be studying.

Simon Goodson, SVP, Lessor Customers for Rolls-Royce, said all new technologies are being considered. RR openly acknowledged development of the Advance and Ultra Fan engines and continues to look at open rotors.

PW’s Deurloo said he GTF is PW’s path to the future, including large engines.

Fixing the problems

Deurloo acknowledged PW presented its A320neo customers with “challenges,” a word he used repeatedly because of extended start-times when the GTFs first entered service; combustor and bearing issues; and fan blade problems.

Bombardier is also suffering because of fan blade issues.

Fan blades had quality problems and PW woefully underestimated the supply-side production.

Deurloo said PW is doubling production facilities which will triple the output. The start-up issues were resolved months ago. This leaves the combustor and bearing problems, fixes for which are in process and modifications ready next month.

Fifty-three A320neos and Bombardier CSeries with 13 operators are in service with the GTF, he said.

Others at the ISTAT conference with knowledge of the performance said the CSeries economics are 1%-2% better than expected. The A320neo GTF is also better than expected on fuel burn.


Gael Meheust, the new president and CEO of CFM, noted that the first LEAP engine, the 1A for the Airbus A320neo, entered service only a short time ago. It’s meeting its promise of 15% reduction in fuel burn compared with current generation engines, he said. In fact, on a delivery flight to Air India, Meheust said the flight crew reported lower than expected fuel burn, with the airplane arriving in India with more fuel left than planned.

Utilization is up to 11 flights a day with as little as 25-minute turn-times. More than 300 hours have been flow by Pegasus Airlines, another early LEAP operator.

An Airbus insider told LNC the LEAP-1A is performing well with no significant issues.

The LEAP-1B for the Boeing 737 MAX flew 1,400 hours on the MAX 8 test fleet. Entry into service is slated for the first half of this year, months ahead of schedule, Boeing said earlier in the day.

Meheust said the first flight of the LEAP-1C, for the COMAC C919, is weeks away.

CFM’s biggest challenge now is ramping up production to service the backlog of some 14,000 engines.

22 Comments on “Engine OEMs diverge on technology for next generation

  1. This is the first public announcement that the LEAP-1, in any incarnation, is meeting the 15% SFC reduction target in service. There was much speculation that it wouldn’t after the report of a 5% miss by an early prototype, speculation that was fed by vague statements from GE such as “we will meet contractual commitments”. One wonders why GE didn’t just come out a year ago and say the engine has hit the 15% reduction target.

      • Just one flight isnt much to rely one. Maybe the winds were favourable as well
        ‘on a delivery flight to Air India, Meheust said the flight crew reported lower than expected fuel burn’
        Using the phrase ‘compared to current generation’ is a wide target, as of course theres been improvements within the current generation.
        In a way it reminds me of the way car companies manipulate the tests for fuel consumption to get the results they want, we will have to wait for 6 months use to see how it pans out- unless they have non disclosure agreements?

  2. P&W with the GTF is the future.

    I have yet to see open rotor produce a real option.

    Along with its inherent technical issues, its a one off offering for an optimized airframe. I.e. you are stuck with one engine mfg.

    Tubofan under wing or jet on top of frame in a lifting body are not limited.

    You can hang or support a turbo fan

    P&W looks not to have been in the highly competitive commercial industry with a new product and has suffered for that.

    GTF is still best current and the future and all the NASA studies for highly efficient aircraft are a GTF solution , and not open rotor.

    Probably one impediment is P&W has the only offering and no one else has that until 2025 or so.

    Puts a kink into the launch of a new aircraft. Offer P&W now and the others as they catch up.

    Boeing should have offered the scaled up P&W for the 787 as soon as they could get it to market as the third engine option.

    You can see what the mfgs is saying (GE) tell use where you are going so we can offer a product.

    • The Indian Aviation regulator seems to have identified a new – and apparently significant – issue regarding the gear box on the GTF, involving emergency shutdown and metallic chips being detected.
      More frequent borescope inspections would be required as a result of this issue.
      Is there any further details on this?

    • Seems Boeing is starting to move closer to the launch of a new “Narrow Body Twin aisle (NBT)” to replace 757’s, 767’s and accommodate growth from the single aisle market?

      The LEAP’s are “done”. The GEnx and GE9X are nearing the end of their respective development stages, so what’s next for GE? P&W is probably the best positioned for a GTF, but I put my money on a GE to be on the wing of 797 when it takes off in 2014/5. Thrust requirement/s, your guess is better than mine, but should be ~45K-Lb if it wants to be really competitive?

      United Airlines is a most likely launch customer (as is the total cancellation of their entire Airbus order without replacements?).

      • If RR can’t do a GTF before 2025, I don’t expect GE can either, maybe not that soon.

        • Just looking at realities;

          The main initial/launch customers will be from the USA, GE is American.

          Will ANA go for R&R if they have a choice, or Quatar and Indigo with P&W? These are potential 797 customers, fuel consumption is not everything.

          A “small/narrow” Twin Aisle will be a good move from Boeing. If it is a comfortable 2-3-2 the low cost carriers could squeeze it to 2-4-2, etc.

          First –>1-1-1,
          Business –> 1-2-1,
          Econo + –>2-2-2,
          Economy ->2-3-2,
          Low Cost –>2-4-2.

          Looking forward to the 797, hope it incorporates something “retro” like a 757 “look-a-like” nose-section. There is something about a 757 that excites you, the 797 maybe do the same, in its own way?

  3. I don’t think the engine manufacturers will wait for 15% or 25% improvement. 10% will be enough for a new narrowbody. Why? The next iteration of CFRP will produce an airframe with 70% CFRP. Airbus have already produced a CFRP wing box. Add the next iteration of skinny wings, thereby reducing drag, a new narrowbody with 10% engines will be 25% better than the NEOs of today.

    If Boeing launch, Airbus will follow for they gave the 787 a six year start. Airbus won’t do that again

      • Three-surface congiurations have proven to be less efficient than “kites” (tailplane aft of wing) in practice. More positive theories are based on 2D or 2,5D aerodynamic models. Real life is 3D.
        Body lift is a red herring – a very inefficient way to create lift. Think of the body as a very low aspect ratio wing.

        • Isnt the Piaggo an example in practice and has a tailplane aft of wing as well. This isnt the Beechcraft Starship. What ones were built that didnt work ? Or did you mean they dont work in the computer modelling ?

  4. Anyone knows what’s happening to the TRENT 7000? Things seems to be very quiet on that front.

    • Well, they’re selling them so presumably things are going OK. Aircalin seem to the latest customer, December 2016.

      At least, they’d have to be giving their customers some pretty firm guarantees which they’ll be obliged to back up with a product that works as advertised.

      RR have been pretty good over the past decades at getting engines on wings off the ground and into service.

      I had an interesting chat with an RR engineer about the approach taken, whilst on a course about QFD. Quality Function Deployment is a systems engineering methodology intended to get the quality of a product right at the very beginning of a project, not part way through after prototyping. It involves a lot of careful thinking and de-risking prior to actually designing a prototype. The intention is that the very first unit off the production line is built to the right quality. Basically it forces you to honestly confront what it is that is important, and just how good does something have to be beyond the basic requirement?

      However, with something as large and as complex as an aero-engine, the answer to the question “when is a design’s quality good enough” is a bit vague. There’s a lot to win by going beyond certification and meeting the initial performance spec.

      In my view RR solve this vagueness to a large extent with their Total Care package. Once a design basically works and is certified, they can do a certain amount of “finishing off” in service at no risk or cost to their customers. Customers get adequate engines earlier, RR get a lot of testing and observation of engine performance, and improvements come along down the line to the benefit of all.

      • Thanks Matthew, was hoping on the quiet that RR is aiming at getting the TRENT 7000 on the wing of the A330-900 with ~75K-Lb thrust capabilities readied, that could be “worth” a few months delay? (The T7000 engine is ~1.6T heavier than the 72K-Lb thrust Trent 700, an extra 3K-Lb will improve it’s thrust/weight ratio).

        A higher MTOW 330-900 (~248T?) is required for extra fuel capacity to push range to at least 7000 Nm (currently ~6500Nm) if it wants to get anything nearer to that of the 787-9’s ~7600Nm range.

        Maybe Airbus should consider a 330-900 LR variant with higher fuel capacity but reduced freight capabilities when operating at MTOW. There are airlines out there looking for the A330-200’s range in the 330-900NEO.

    • Requires constant vigilance or better a really solid culture that endures, unlike Boeing’s 787 botch with internal processes and suppliers that cost them dearly in delays and probably put cost and weight in the design because people couldn’t trust the other department/supplier. Leadership is key.

      https://bbt.mediaroom.com/our-culture is a solid example of good culture.

  5. I’ve been told off a number of times that the 3-shaft architecture is over. I’m not sure. Most agree that the 2-shaft architecture is hitting a wall. But, I’m not convinced that the technology exists to support a 50KIb+ GTF. It will come but not in the next 10-15 years.

    I think RR will offer a 3-shaft engine for the next generation of engines. PW are committee to GTF but does their technology have the maturity. GE aren’t saying much, but we are all sure they will come up with something.

    • P&W says it can scale up the GTF to any size.

      I will believe them and their 20 years into it

  6. Can anyone tell us the absolute factual numbers? What are the TSFC data, or Airbus Blue Book values for these engines?

    The public claims of FC improvements (15-16%) presented by the sales people are relative to whatever they consider as their baselines (CFM56-X/V25XX – which btw. are not equal and vary by ratings) and are consequently misleading and open to .. bamboozling.

    In addition, function of engine+nacelle+pylon weight the actual aircraft SFC data also change with engine models…

    Also needles to say that what enthusiastic pilots report about one flight are less than objective data.

    So when can we eventually get rid of the emotionally loaded, not objective argumentation and compare apples-to-apples?

  7. Indeed, one flight is completely inadequate to judge fuel consumption by. Among factors to consider are:
    – weight (people, baggage (Grecian urns, gifts from family, etc. have been a cause on charters), cargo like spare parts)
    – did crew get planned altitudes from ATC? Can be a challenge if flying across prevailing flow, such as experienced by PW 707s running Malaga-Vancouver.
    – Winds were mentioned.
    A nice experience for delivery flight crew though.

    While there are people in Airbus and Boeing who would cheat, I doubt they could get away with it for long on SFC as airlines would be watching closely. I presume the likes of Delta still have the technical capability to measure closely.

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