44% supplier shortfall for GTF now showing impact

Sept. 6, 2016, © Leeham Co.: It was a stunning admission, one that produced the biggest headlines at the United Technologies media days in June: 44% of the suppliers on Pratt & Whitney’s Geared Turbo Fan engine weren’t performing to the UTC/PW standards.

The impact of this was seen today when Bombardier announced it will deliver only half the anticipated 15 C Series this year because of engine delivery issues by PW for the GTF powering the new airplane.

Bombardier and PW pointed the finger at its supply chain for the delays in delivering engines.

Airbus issues

Airbus continues to have slow deliveries from PW after a bowing of the engine shaft was revealed under certain conditions. The A320neo is powered by a different version of the GTF than the C Series. It’s also powered by the CFM LEAP engine, which only recently went into service. There are no known issues with the LEAP.

PW said at the media days the bowing problem has been fixed, along with some software glitches. But during the factory tour, only two engines on display were identified by PW as the first production engines to have the fix.

Given the number of airplanes beginning to line the Airbus production line, reporters on the tour were surprised there weren’t more engines apparent and ready for shipment.

Airbus still has a reported completed 20 A320neos awaiting the GTF engine.

Neither Embraer nor Mitsubishi are affected at this time. EIS for their GTF-powered EJet-E2 and MRJ90 aren’t until 2018.

Airbus, Bombardier and affected customers are reported to be seeking compensation.

 

81 Comments on “44% supplier shortfall for GTF now showing impact

  1. Kind of an unfortunate irony given that the CS series are aiming to have the smoothest ever EIS and thus steady deliveries and continuous supply. A plane is only as good as the sum of its parts. But I think this will be remedied. GTF was bound to have teething difficulties with the amount of unknown and unforseen variables in the mix.

    • There is a difference between teething problems (which it has had) and not getting your supply chain organized when you know long in advance what is going to be needed.

        • There is more to it than the supply chain, such as the quality of design and quality of manufacturing….

          • Dag nab it, I knew I was missing something.

            Imagine the part having to work to.

            Thank you for bringing that to our attention.

          • True. A part is only as good as the quality if its design and manufacturing. Sorry I was trolling a bit there. The Boeing 787 was plagued by crap parts and they had outsourced batteries to some 2nd rate company in Japan. In the case of PW it seems to be supply chain.

          • ROFL.
            Boeing was plagued by crap management and ham fisted design decisions and also apparently got quality as paid for.

            The complete batteries/charger/use concept was imu a negative tolerances design.

            The same suppliers tended to delivered rather better quality when aided by sane design decissions under an adequate oversight/liaison framework.
            Still surprising that poster bring up the “Boeing can’t do wrong and was entangled by subpar suppliers” broken record again and again.

  2. First Boeing with a supplier subcontractor problems/debacle on the 787, now P & W . Maybe the old ways are better after all. When the final blll comes in, outsourcing will be the most expensive option.

    • Funny though how it never bites someone at the top.

      The Charleston 787 contract workers debacle is another one.

      We don’t need them for 3 months, lets lay them off, as the system then melts down.

      Darn it, they aren’t very helpful, they are supposed to be nuts and bolts, disposable and throw away when done.

          • If you had been following the program you certainly would have.

            It was another startling bit of gross mis management.

          • I guess you missed it when they dropped a whole fuselage section ?

          • Are you referring to the A340 in Toloose that climbed a fence during an engine test run? The airplane had to be scrapped.

          • Andy:

            Please read what is printed.

            I specifically said they DROPPED not ran into something and said thing that was DROPPED was not an aircraft but a fuselage.

            I grew up flying, I know the difference between a Super Cub, Cessna 180, Tri Pacer not to mention the vast difference between an A340 and a 787.

            For someone who purports to have various long aircraft industry experiences and not being able to comprehend a simple statement gives one serous pause in accepting that.

          • TW, what are you talking about? The A340 in Toloose that climbed a wall during an engine test run was an AIRPLANE with wings, engines, etc. As you probably know the airplane had to be scrapped.

      • Andy:

        You are the one that brought the A340 into this. You should read the post.

        I clearly said, FUSEALGE SECTION, i.e. not an A340, not an Airbus, not in Toulouse, Not in France , Charleston SC, USA, Boeing factory.

        Obviously a waste of time trying to get through.

        • An A340 climbed a fence in Toloose during an engine test, didn’t it? The airplane was scrapped, wasn’t it?

  3. Thanks to LNC’s good work, I now have the answer I was looking for. So it’s a supplier issue. Interestingly, after going through so many supplier issues of its own, Boeing is now producing aircraft in record numbers while Airbus is struggling. There are many ups and downs in aerospace and we sometime witness wild swings that seem to come from nowhere.

    One question remains though: how long will it take before Airbus and Bombardier can resume normal production rates? I know that Zodiac has been hiring lately and that they have replaced a number of management positions, but my understanding is that they are still far from a stabilized recovery. Unfortunately I know nothing about P&W’s problems other than what I have learned here. Now I need to know who, what, why, where and when. Perhaps LNC can enquire for us. 😉

  4. The word for the day on the C Series: “Snakebit”. And somebody’s still LYING on the PW1100G for the neo: Al Baker at Qatar, or Leduc at Pratt and Whitney. My take is that it’s Leduc/PW. His somewhat arrogant attitude is the engines are performing fine now– they’re “golden”! But there are apparently still too many “false positive” engine warnings.

    • And as I noted in another post, AB may be seeing that not only the affects of the rotor bow, but supplier issues affecting ramp up.

      that may be why he has refused (5?) A320NEO so far and may dump the buy.

      • It’s not really refusing to buy them if they’ve got no engines,maybe this puts Al Baker in a different light.
        This is one of the biggest and fastest engineering ramp ups there has ever been outside of total global war. It’s not surprising that it’s run into trouble, what is surprising is how optimistic aerospace companies are and don’t leave enough margin. Boeing, if they’re not lying again,seem to of got their act impressively together with the Max although plenty could go wrong with the Leap engine.

        • While it is, it also is long in coming, this has been years in development.

          I got suspicious when Av week reported on how hard they were working on the sup0ply chain. Hmm, note to self, if they are making a big deal out of it there is a problem.

    • So quickly some forget
      “Qatar Airways threatens to cancel B787 orders due to “continuous” delays”

      • Keep dreaming. Qatar operates a large 787 fleet and is taking delivers of more 787s.

        • Thats was because they werent getting them on time back in 2009. I wonder what the hold up was ? Anyway they began arriving halfway through 2012 so ABB had 3 years to put a flea in Boeings ear. Then they were grounded in 2013.
          As you said hes happy with the 787 …now. Like the USAF will be with the KC-46…eventually.
          The 737Max will be great too…just like the 777X… just as Boeing is promising everyone.

          • One reason I question AB is because of the 787. He certainly was justified in cancelling (both legally as well as by the wool pulling to put it kindly that was going on)

            I don’t see any issues with the MAX, engine still have to prove out both on the B version and the A version. C version is not an issue for a long time.

    • What a shame they selected the American engine rather than the half French one used on the Max!

      • Grubbie:

        You may want to check your facts, the engine is a co development of MTU and P&W, P&W has their name on it but MTU has a big part in it.

        The Gearbox is Italian .

        A big chunk of P&W is Canadian.

        I believe the Japanese partners also are making parts of it.

        And they got bit when they gave tech to (China as I recall).

        So much for Apple Pie and Mom.

        • Yeah, I did sort of know that, but I didn’t know about the certification thing.Its getting harder and harder to play the patriot card. Which nation can we pin the blame on?

          • no bother with that.
            The “patriot card” voids all facts anyway.

            You’ve just seen a perfect example further up 🙂

          • I also did not know about the IAE certification but suspected full group involvement in reality if not in name from what I was seeing as the partners sourcing.

            Sort of the risk sharing without the hula balloo.

            By that standard, CFM is 50% American, P&W 25%? (grin)

            So no matter where a CFM is assembled its half American at least!

          • “So no matter where a CFM is assembled its half American at least!”

            There are two assembly lines, one in the US and the other in France. I don’t recall any other international cooperation in aerospace that has worked so well as that of CFMI.

          • I assume half the parts come from each side, I don’t know if they have duplicate plants say for fan blades or each side splits the mfg and supplies half the parts to the other?

            Oddly, the Silvercrest Snemaca engine has been a bust, had to re-design. Not sure how you assess that in comparison to its extremely successful collaboration with GE.

  5. So what exactly does “44% supplier short fall” mean? Seems to be related to cost, quality, and timeliness. Well, all of those are inter-related. So if it’s not working out for P&W, something’ll have to give.

    I can’t believe after all this time that there’s major quality issues with supplied parts. There’s been plenty of time to get the parts build processes sorted out. If suppliers (internal and external) have spent all this time making development parts and then gone “oh, we can’t mass produce them to quality” then one wonders how it is they were still in business in the first place to pick up the development contracts.

    Is this P&W trying to clamp down on costs now, at the very beginning of the program, before it’s really getting into its stride? If so, well I’m no expert, but surely it’s best to be less worried about cost at the moment and just get the program running smoothly, now, without anymore delay, without haggling about how much supplier’s have to sell their parts for. I mean, if P&W are screwing their suppliers now, guess how motivated they’re going to be to do things to timescale. Not very. Never, ever, beggar one’s suppliers.

  6. What we see today might be related to the unprecedented number of narrowbody aircraft on order. The Leap does not appear to have any problems at the moment and the pressure is somewhat less for them because the MAX is not in service yet. This should give CFMI enough time to sort things out with suppliers who will have to deliver the parts for this engine in exceptionally high numbers for a new engine.

    However, the situation is entirely different for Airbus and Bombardier, both of whom having already started to deliver their respective new aircraft at a time when the suppliers are simply not ready to face such a high demand for engine parts coming from so many OEMs all at once.

    The situation is crazy when we stop to think about it. Perhaps we have not discussed enough in this forum the implications for suppliers of this gigantic surge in aircraft orders and the corresponding ramping up in aircraft production. Just look at Boeing’s numbers for aircraft deliveries this year, it’s mind boggling.

    If there is one bubble about to burst it is this one: the suppliers bubble. The expectations from the suppliers, in terms of output capacity, are perhaps unrealistic. I don’t really know, I am just asking the question.

    • My definition of a bubble: inflated expectations, based on unrealistic assumptions.

  7. “… PW pointed the finger at its supply chain for the delays in delivering engines.”

    who will produce fulll tilt for stuff that may very well need changing out in the near future?

    • It was pointed out in the Av week article that one was fired, they seem to be working at getting two sources for everything .

      Of course once you fire one, you are down to one!

  8. Some excerpts from a Reuters article about Pratt & Whitney’s problems:

    Three industry sources said the U.S. engine maker also faces challenges in bedding down the manufacturing techniques for the engines’ novel “hybrid-metallic” fan blades, the world’s first to be made mainly from aluminium alloy.

    While the sources said there is nothing technically wrong with the lightweight blades, one said the problem was linked to perfecting advanced new industrial methods, leading to some quality problems and slowing down deliveries.

    “The process is not yet automated enough; it remains too much of an artisan process,” the source said.

    The reported fan-blade manufacturing problem is at least partly responsible for delays that prompted Bombardier to more than halve its forecast for deliveries, two of the sources said.

    http://www.reuters.com/article/pratt-whitney-engines-idUSL8N1BI51X

      • Shades of Yuasa hammering out battery grids for the 787 by hand (aka Artisan and quality control highly variable in an unforgiving battery type) .

  9. Some of the supply issues may well stem from the teething troubles. If new components had to be designed, tested and then put into series production, it would take some time to bed down.
    The few engines now in operation may be using hand built components?

    • Probably. As GE saw with its move to industrialization on the GENx, it sometimes really bites you.

      As a mechanic my take is an engine should be certified with the parts its in service with, not a pre industrialization engine system that then changes parts and or processes.

      RR probably had the same thing on the A380 engines with that bad part.

  10. LNC had a story about the new materials used in the GTF back in 2015
    leehamnews.com/2015/04/01/pratt-whitney-material-considerations-in-next-generation-of-engines/

    Its not only the materials, the GTF is the first ultra high bypass ratio engine (12.2:1)

    • True, but their parts are not as advanced as GE, they are advanced for P&W and its IAE group.

      The architecture is more advanced, but P&W has not kept up with the pushing materials to the MAX (pun intended)

      Not a bad thing but any advance into a new area has its problems even if someone else is doing something more advanced successfully, its not you and you have to get to a different level.

      That said, that also is a major upside to the GTF as one with the same advanced materials GE is using has even more fuel burn improvement. Its why RR is desperately (grin) trying to catch up to GTF.

      • “Its why RR is desperately (grin) trying to catch up to GTF.”

        It will be interesting to se what the combination of RR’s three-spool technology does when combined with P&W’s GTF technology.

        • My impression up to now was that we will not see 3 spool _geared_ engines ?

          with the rpm transformation via the gear reduction the turbine sections can all turn faster ( with fewer airfoils in a smaller
          diameter arrangement).
          With the gearbox you can match LP (fan) rpm to IP (2. spool) rpm and a common turbine section.

          • My understanding is that RR is hard at work incorporating the two technologies. The idea behind a three-spool system is similar to the GTF’s: to optimize the rotational speeds.

            With a three-spool system you can separately optimize the rotational speeds of the Fan, Intermediate Pressure Compressor (IPC) and High Pressure Compressor (HPC), and their associated turbine assemblies (LPT/IPT/HPT).

            The GTF concept achieves more or less the same thing via the decoupling of the Fan from the LPC (equivalent to the IPC). So in both systems (tree-spool and GTF) each of the three groups (Low/Intermediate/High) turn at a more optimized speed, which increases the overall efficiency of the engine.

            By adding a decoupling gearbox to a three-spool the latter essentially becomes a four-spool in the cold section, like the GTF has essentially become itself a three-spool in the cold section. In the former we would find four different rotational speeds (Fan, LP, IP and HP), while in the latter we already find three (Fan, LP and HP); but only in their respective cold sections, that is upstream of the combustion chamber. In the hot section, where the turbines are located, the number of groups remain the same in both cases (three-spool and GTF), that is, three and two respectively.

          • My understanding is that hey are calling it 3 spool when in fact its two spool.

            Harley had to keep its engine noisy as they hung their hat on it. RR is stuck with two spool they mader such a big deal out of it.

            Years back Cat dissed Detroit Diesel (and Cummins) for the unit injector. Their system was so much better (and complicated and took a l0ot of special tools)

            Lo and behold, they quietly went to those as they were far more effective emissions wise. DD made the first ones for them.

            RR to will quietly sidle it through.

          • “My understanding is that hey are calling it 3 spool when in fact its two spool.”

            RR engines use three concentric shafts to drive each of the three spools: one shaft drives the HP Compressor, a second one drives the IP Compressor and a third one drives the Fan. Whereas in any two-spool engine we find only two concentric shafts to drive only two spools: One drives the HP Compressor and the other drives the LP Compressor, to which the fan remains attached.

            The GTF ressembles the three-spool in a way, but still retains the two-spool architecture. The similarity between the two stems from the fact that in both systems the Fan is decoupled from the LP Compressor. The GTF accomplishes this via a reduction gearbox whereas the RR three-spool does the same by providing a third shaft for the Fan. I am a big Fan of both systems.

          • While I think the GTF is the future, I am not a 3 spool fan (pun)

            It adds complexity and does not give a significant advantage though its touted to (supposedly over longer range flights).

            Its also more costly and maint is a major issue.

            So while RR does use 3 spools now, what they are calling 3 spools in their GTF from what I understand is actually two and the aspects of the GTF itself.

            So its a slice a hair thing to prove you are still 3 spool.

            I don’t blame them but I don’t buy it either.

          • Three shafts = three spools.
            Two shafts = two spools.

            I agree that the three-spool doesn’t bring that much more in terms of performance and economics, but it led the way for the GTF, which is everything the three-spool concept was aspiring to be. It will be interesting to watch what the combination of the two technologies will yield. I expect the GTF to help RR better exploit the three-spool potential.

          • Three shafts = three spools.
            Two shafts = two spools.

            Three shaft := 2 spool + one “detached” shaft via the gearbox.

            with the gear reduction for the fan you can have both IP and LP _turbine_ on the same higher rpm level that gives good efficiency and lower number of airfoils.

  11. I might be barking up the wrong tree here but it occurs to me that Boeing suppliers have been under a lot of pricing pressure lately. Are engine makers pushing supplier prices in the same way that Boeing is? Engine makers are pretty much under the radar but I assume they could be, I honestly don’t know, so I am asking here? That would mean that suppliers might be having trouble financing production of new parts and ramping up.

    • Quick Googling does show PW as having the lowest net profit margins for it under its UTC parent’s various lines of business/subsidiary entities. There’s every incentive, from the UTC parent’s management’s perspective, to squeeze PW suppliers, and hard. Margins need to come up to 15%, minimum, from 12 to 13% to be “in line”. It’s very similiar to Boeing wanting to get to the mid-teens, though Boeing’s still sub 10%, as I recall.

      • Boeing asked Goodyear (UTC) to lower their price for the 777X landing gear, but UTC could not satisfy Boeing’s request and they lost the contract to Héroux-Devtek.

        • We will see how that works out!

          I would also say UTC would not, not could not.

          And what in the world is wrong with 12%. If I had a 12% left over at the end of each month I would have retired now.

          Bunch of winey butts

          • You are right, I should have used “would” instead of “could”. My mistake.

          • You’re not thinking clearly here as a conglomerate ceo manager. It’s been pretty clearly established–since at least the days when Jack Welch was in his prime at GE–that divisions/subsidiaries/lines of business “hit their numbers” (barring some very unusual, very short term circumstances), or were “gone” (sold, or divested). Welch was upheld as an “el Supremo”/and the standard in his prime. GE did hit their numbers (pre 2008) and the stock market rewarded him and GE very handsomely. (Many of his employees, managers, and others didn’t particularly like him–“Neutron Jack”–or his management style.) But, in general, you’ve got to have consistent profitability, some growth and, possibly, some leverage, to survive much below a 15% net return. (Basically you’re then like an old school, “safe for grandma”utility company and stock.) The issue of adequate net returns gets into things like market allocation of capital and finance theory that there are textbooks and textbooks written on. And, to sum up (pun only slightly intended), I’ve seen fairly recent speculation that UTC should package up PW and Aerospace and divest them to improve UTC’s financial returns. Lastly, what you think is an adequate return at 12% personally, is sadly not particularly relevant when you’re playing “in the big leagues”– requiring public or hedge fund equity. Hope this helps!

          • Well my head hurts, so maybe there is something wrong with the system and not my take?

      • When there are several engine offerings airlines negotiate the airframe and engine separately. In those cases, engines can end up with extremely heavy discounts. That does not mean that the engine manufacturer loses money on the contract since later sales of engine proprietary parts are extremely profitable. It is sort of like the razorblade business. You get the razor for almost nothing but pay thru the nose for razor blades.

        • I think you might have put your finger on something here, if you sell the engine for nothing (profit wise) you are deferring the profit. That makes finding capital to start up production of a new line hard as instead of a return in the first few years you might be deferring the profit for a decade of more. It puts a lot of pressure on managers to keep investment down from the start.

          • “It puts a lot of pressure on managers to keep investment down from the start.”

            Make the model as simple as possible but not simpler ( Einstein).

            What you see is a major deficiency in process understanding in “run of the mill” managers and the shareholder ecology in general. If you think in 3 month segments your intellectual grip on a process spanning many years if not decades is tenuous.
            People still appear blinded by the leveraged “earnings” in the financial transfer sectors. But those markets are not really productive but work as a “highwaymen toll taking” endeavor.

  12. @MontanaOsprey

    “I’ve seen fairly recent speculation that UTC should package up PW and Aerospace and divest them to improve UTC’s financial returns.”

    PW and Aerospace have already been “packaged up” before. This was accomplished by none other than Alain Bellemare, the present CEO of Bombardier, then working under Louis Chênevert, the previous CEO of UTC. Chênevert was ousted and Bellemare was left in charge of the new Aerospace division that now included P&W and Aerospace Systems, and which was managed as a single business unit. But in the meantime the board had decided to bring their own man in and got rid of Chênevert. So the new division was led by Bellemare under a new CEO who promptly fired him. So they both lost their jobs in quick succession. Today P&W and Aerospace Systems are again managed separately and directly from the UTC headquarters in Connecticut instead of North Carolina.

    That being said, if P&W and Aerospace were divested UTC would become a much smaller company. In my opinion the reverse should be done, that is P&W and Aerospace Systems should again become a single company and the rest divested.

    • Per your last paragraph, the divested company, while much smaller, would be considerably more profitable. The market could easily reward it with an expanded multiple and higher stock price–as long as it still had reasonable growth prospects. The management of the combined “UTC Aerospace” (including PW) would still face market demands for higher returns–probably 15% or greater. You don’t get to escape these demands, given your voracious need for capital in a cyclical industry, and on this global playing field. I think this thinking is also validated by Muilenberg at Boeing trying to get it to the mid-teens in net profitability. The only “escape” I can possibly think of at this moment is an Airbus acquisition of it–for some reason, they seem–so far–to be able to live on three to five percent net margins. (A lingering result of their government ownership?) And that possible acquisition might very well not make political and expanded capital need sense.

  13. @MontanaOsprey

    That’s fine if you look at it strictly from a financial perspective. But for me money is only a tool to accomplish various things, not a goal in itself.

    That being said, when Bellemare was let go by UTC he was snatched by Bombardier who were going through a major restructuring of their own at that time. The irony is that they were doing exactly the opposite of what the duo Bellemare/Chênevert had attempted to do and which was eventually rejected by the board. What these two had decided to do was to regroup all the aerospace activities under one umbrella after the acquisition of Goodyear Aerospace had been completed. Goodyear was chosen as the headquarters of this new division which would comprise P&W, Sunstrand and Goodyear. Bellemare was to head this division from Charlotte and report to Chênevert in Hartford. Bellemare had been CEO of Sunstrand until that time and had been CEO of P&WC before that.

    But the board saw it differently and got rid of these two guys and did what BBD had done only a few months earlier when they dismantled Bombardier Aerospace and made it into three separate business units: Business Aircraft, Commercial Aircraft and Aerostructures. And instead of reporting to Aerospace in Dorval they now reported directly to BBD in Montréal. UTC did the same when they dismantled the short-lived UTC Aerospace and made it into two separate business units that reported directly to UTC in Hartford instead of Aerospace in Charlotte.

    UTC and BBD are two very different companies and what is good for one is not necessarily good for the other. Personally I was against the dismantling of Bombardier Aerospace when it was initiated. But today I better understand the value of the move and now consider it Beaudoin’s best decision since his appointment as CEO in 2008. However, for UTC I hold a different view and liked the idea of regrouping the aerospace activities under one umbrella because this would facilitate the integration of Goodyear into the UTC organization.

    The main difference between BBD and UTC is the size. I think UTC as a whole is too big to run two aerospace business units on one side and an array of extremely diversified business units on the other. I find the level of complexity mind boggling compared to BBD’s two division (Transport and Aerospace) and would get rid of all non-aerospace activities and manage UTC as three separate business units: P&W, Sunstrand and Goodyear. I like the way BBD is structured today; we have Transport on one side and Aerospace on the other. These two activities are more compatible than say Otis and Sunstrand within UTC.

    Before I conclude I need to clarify one thing. The scenario I have reconstructed for UTC is based on personal observations and may differ somewhat from what really happened behind closed doors.

  14. If there was such an event, it was due to oversight by someone at the assembly line, and not by factory management.

  15. @TarnsWorld

    I think I better understand now your objections about the Rolls-Royce three-spool adaptation of the GTF. I said in a previous post that “we would find four different rotational speeds (Fan, LP, IP and HP).” But that is not the way Rolls-Royce intends to do it. At least not with the project they are currently working on: the UltraFan. In fact the three-spool architecture, as currently applied to the Trent, will be retained without any significant changes other than the addition of a reduction gearbox. This means they do not intend at this point to add an LP compressor. What this implies is that the LPT will continue to drive the Fan instead of an LP Compressor. Although it would be more accurate to say that the LPT will now drive a gearbox, which itself will drive the Fan. This “simple” operation will save Rolls-Royce a great deal of money by allowing them to retain the current engine architecture, which, need I remind you, is a three-spool through and through. But is now implemented in a different way than you and I would have expected.

  16. @Uwe

    “Three shaft := 2 spool + one “detached” shaft via the gearbox.”

    In the UltraFan the LPT drives the Fan via the gearbox, the IPT drives the IPC, and the HPT drives the HPC, each with its own shaft. That entails three sets of turbines. In a two-spool you only have two sets of turbines. That is if you look at it from the hot section perspective. But if you want to look at it from the cold section perspective then yo have two compressors and one fan. And from that perspective the three-spool and two-spool engines are identical since they both have the same combination of LPC, HPC and Fan, except that RR calls the LPC the IPC.

    Which begs the following question: From which perspective is the type of engine defined, the hot section or the cold section? Answer: None of the above. It is defined by the number of shafts it uses. RR is the only manufacturer that uses three shafts in the architecture of its engines. Comparing the Trent to the UltraFan is exactly like comparing the GTF to the CFM-56, the latter being both two-spool engines while the former are both three-spool. So the UltraFan it’s not “2 spool + one detached” anymore than the GTF is 1 spool + one detached. The UltraFan is a three-spool, period.

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