Odds and Ends: Repairing the Ethiopian 787; more on A350-1000 stretch; new RR engine study

Ethiopian 787: Dominic Gates at The Seattle Times has a detailed story about how Boeing is repairing the Ethiopian Airlines 787 damaged by a fire at London Heathrow Airport earlier this year. Boeing doesn’t comment for the story–nor for any others–but Gates’ detail in his piece makes for quite interesting reading.

Stretching the A350-1000: More on this topic from Aviation Week. Aside from the technical considerations for the airframe, Rolls-Royce would need to bump up the thrust of the engine to around 104,000 lbs, we’re told. Also: there is the matter of production. Airbus is considering a second production line for the A350, but no decision has been made.

Rolls-Royce studies new engines: Rolls-Royce is studying a new line of engines, according to this Bloomberg article.

53 Comments on “Odds and Ends: Repairing the Ethiopian 787; more on A350-1000 stretch; new RR engine study

  1. I find it odd that RR is working on another new WB jet engine, the RB-3039. But what is really needed is a new NB engine, beyond the new engines offered by CFMI and P&W. Both Boeing and Airbus have said they need a new engine to build new NB airplanes to replace the current and near future B-737 and A-320 series. These new NBs will be sold in the thousands to replace the B-737NG and A-320CEO, and possibly the MAX and NEOs, too. IF RR won’t work to develop this new NB engine, perhaps GE and P&W will.

  2. The preliminairy study on a further A350 stretch was done in 2009-2010 when the A350-1000 upgraded from a “simple stretch” into a long range heavy machine, incorporating dedicated Trent-1000 engines, a bigger landing gear and wings enlargement. It became clear Boeing was going to upgrade the 777 too, after the 787. That took longer then anyone expected.

    I think Airbus is forced to show their carts earlier then they hoped, after evaluating the LH A350/777X decision. All major 777 customers have ordered A350s, except ANA, AA and Korean. To prevent them and Boeing sales people assuming the -1000 is the end of the line, they leak the -1100 studies.

    It doesn’t take rocket science to determine the OEW / CASM will be relatively low.

    • keesje, a stretch of any airplane is more than adding a few more frames and stringers to the fuselage. Will it need more engine power? Wing modification? Landing gear, maybe even taller gear? What about electrical and hydraulic systems? Avionics modifications, including software. Of course it may also need more exit doors. Airbus engineers know this, so do Boeing engineers. In short, is an A-350-1100 even doable?

      • Correct KCTB, but most will be done for the A350-1000, that one already gets more engine power, wing modification, landing gear (3 axes). The A350-1000 and -1100 would have more in common than the A350-900 and -1000.

        Like the 777-200LR and -300ER are more alike then the 777-200ER and -200LR.

      • The 767-400ER is a primo example of an unsuccessful stretch. Longer fuselage; raked wingtips, new window belt to make it look like a 777; new-look interior, also based on the 777. Uprate the engines and higher gross weight. All for naught: thirty-seven were sold to two customers, Delta and Continental [now United].

        The 767-400ER was completely outclassed by the A330-200. Besides a tide of red ink, its legacies are the new-look interior [used on subsequent 767-300ER’s and retrofit into older 767’s] and the proprietary raked wingtips [almost a Boeing trademark, used on the 747-8, the 787, and the P-8]

      • 767-400 versus A3[34]0-*

        What you see imho is the difference between “grafted on” and “designed in from the onset” ( compare Intel versus Motorola CPUs. Only in the CPU market inventive promotion had a much longer lifetime versus a well planned product. )

        • Well then, it seems to me when the A-350 was going through all those design phases, Mk.I through VI, the so-called A-3511 was not part of that. So, I guess you are right, if it happens it will be grafted on.

    • “It doesn’t take rocket science to determine the OEW / CASM will be relatively low.”

      Which would further decrease the need of the two major quad jets in production.

      • Or those 200 people can skip the hub and fly to their destination on a nice 787.

      • Or those 200 people can skip the hub and fly to their destination on a nice 787.

        Sure. Like I’ll ever be able to fly ORK-LAX, PAD-SIN or similar non-stop without passing through a major hub like FRA, LHR, MUC, CDG etc.
        From a logistical point of view you have to connect to hubs from those sorts of airports as well, because you need to be able to drum up enough direct and connecting traffic to fill your plane from PAD, ORK, etc., and you need to be able to offer a sufficient amount of connections/final destinations from the destination airport then. From ORK, EI couldn’t even make LGW work (even though you have a fair amount of connections from there), it had to be LHR, which they now serve six (!) times a day. Basically, every time I leave the country I can see that hub-spoke (via AMS or LHR) is alive and well.

        The notion that an increase in direct connections from secondary airports is going to obliterate hub-spoke is so silly it’s not even funny.

      • Not if you have 200 friends who want to travel between those city pairs daily and for 365 days!!! The 787-8 makes that happen now. Are you not seeing that happen with JAL and ANA now?

  3. Trent is developed from the RB-211, only so far you can push a 36? YO core. The other day I posted the idea that pressure from Emirates to update A380 engines might “give birth” to a new engine series as it was upwards of 500 engines, and size wise in the middle of the B787/A330 replacement to A350-1000 thrust range. Sounds like RR might have the same idea?

    • Starting afair with the Trent1000 cert documents no longer show a RB211-* type string.
      I suppose there then is not much left of the basic BR211 beyond the three spool setup.

      One down:
      RR being kept out of the 777X project was imho a given.
      Too much of a symbiotic relationship between GE, Boeing and GECAS.

  4. I think the Seattle story on the 787 repair is buying into Airbus propaganda on the so called replaceable fuselage sections.

    Airbus could not make the type of fuselage Boeing can because they did not invest in the technology, so they did a look alike aluminum structure as that was the best they could do.

    The BS machine then spun (pun intended) this flaw into a “feature”. i.e. you just replace a damaged section.

    Those sections take up around 1/6 of the fuselage with thousands of fasteners. So rather than slap a patch in they think someone is going to replace that much fuselage (ok if Airbus does it under warranty but a non warnatable damage item?) Nonsense.

    Also, you would need to look at the area of the 787 damage and if it crosses two panels, then you have to replace both panels? Again that is nonsense.

    You would have to total an aircraft to make it worth that and then it would likely be a total write-off anyway.

    Only if and when an A350 sustains large damage will we actually see what they do.

    For any small damage they are going to patch in place just like Boeing would do.

    The Ethiopian 787 is someplace in between, much larger than a ramp incident, a lot smaller than a crash. There is no way to claim anything unless you do an identical cross study of that same damage to an A350 (and its a book thing as it is not going to happen even close to the same even if a ELB did do the same thing as it would be in a different location and likely propagate differently.

    • I think the Seattle story on the 787 repair is buying into Airbus propaganda on the so called replaceable fuselage sections.

      Airbus could not make the type of fuselage Boeing can because they did not invest in the technology, so they did a look alike aluminum structure as that was the best they could do.

      Are you absolutely sure that’s it’s Dominic Gates and not yourself who’s falling for one side’s propaganda here?
      Just checking…

      • On that note – having read the article, I’m willing to bet €20 that Boeing’s next all-CRFP fuselage is going to take a panel-based approach similar to the one Airbus are taking on the A350.

        Those sections take up around 1/6 of the fuselage with thousands of fasteners. So rather than slap a patch in they think someone is going to replace that much fuselage (ok if Airbus does it under warranty but a non warnatable damage item?) Nonsense.

        I suggest you read the article – Boeing actually has to do pretty much the same thing, except they can’t replace individual parts, they have to cut a hole into a structure that’s supposed to integrate most structural functions that on traditional planes were spread between different elements that could, for the most part, be replaced individually. One case in point are the stringers that stabilise the fuselage and are integrated into the carbon fibre barrel, which will be cut here and need to be mended.
        And mending carbon fibre pieces isn’t exactly easy, nor is it easy to validate a mended piece.

        Also, you would need to look at the area of the 787 damage and if it crosses two panels, then you have to replace both panels? Again that is nonsense.

        I don’t think it’s nonsense at all. Replacing parts of the more traditional aluminium frame, removing one or two panels and replacing them with new ones (straight off the production line) – i.e. replacing all parts that compromise structural integrity – sounds way easier and cheaper than having to introduce a compromise in structural integrity in order to remove a damaged structure.
        Also, spinning up a whole new barrel just to be able to cut a piece of a certain size from it (plus some extra pieces, hoping that another plane encounters an incident that will fit at least one of the pieces you’ve cut – otherwise, you get to spin up another barrel for the next incident) seems quite a costly and time-consuming effort.

      • anfromme–“replacing all parts that compromise structural integrity – sounds way easier and cheaper than having to introduce a compromise in structural integrity in order to remove a damaged structure”

        A350 “panels” might just be replaceable, but these panels are very large… the rear section consisting of four panels each about 16 meters long on a -900. Then, the tail section is a fully wound barrel (no panels). Now since the ELT is in a similar location as in the B787, a similar fire could damage the rear part of the three panels (sides and top panels) and possibly the tail section (the ELT is not far from the tail and rear section join).

        We know the panels are made into sections and these sections joined at final assembly…. nose (aluminum), front, center, rear and tail. In a similar fire, would they remove all three 16 meter long panels, the vertical and horizontal tail planes, the APU, the tail cone, then fly replacements panels and tail cone and reconstruct?

      • We know the panels are made into sections and these sections joined at final assembly…. nose (aluminum), front, center, rear and tail. In a similar fire, would they remove all three 16 meter long panels, the vertical and horizontal tail planes, the APU, the tail cone, then fly replacements panels and tail cone and reconstruct?

        Section 19 on the A350 starts a good bit behind the leading edge of the vertical stabiliser and the aft passenger door, so I dare say that – given a fire in the same spot as on the Ethiopian 787 – it would not have been affected.
        Section 19 isn’t all that large, really:
        http://de.tinypic.com/view.php?pic=2hclons&s=5#.UmcEMfk9pI4

        Here is section 16 with section 19 (wrapped in white) joined to it:
        http://www.a350xwb.com/typo3conf/ext/photo_gallery/downloadpic.php?image=fileadmin/media_gallery/photos/aircraft/miscellaneous/aircraft_details_and_structural_parts/A350/A350XWB_aft_fuselage_section.jpg&mode=save&prefix=800x600_1335354942_

        (Looking at that, there’s even a chance that only the top panel would have been affected if a fire had broken out in the same spot as on the Ethiopian 787.)

        In any case, I would really be curious to see how Airbus would approach the same extent of damage in the same area on an A350… Until the first time they need to fix a larger area that’s damaged, we won’t know for sure how much difference their panel approach makes with regard to repair jobs.

        Personally, I think the panel approach still makes a big difference even if you do decide to just patch one (instead of replacing the full panel).
        On the 787, you have the barrel as the main structural component. Cut into the barrel and you have to reinforce that again, which is tricky with CRFP. On the A350, you have a more traditional “skeleton” providing much of the structural stability, so I’d think that bonding issues with a patch wouldn’t be quite as critical.
        This is only relevant with large damaged areas, of course. For ramp accidents and the like I expect patches to be fully sufficient on both A350 and 787.

      • Guess replacing “one or two panels” isn’t all that easy after all. Of course, “we won’t know for sure…”

        From—
        “Replacing parts of the more traditional aluminium frame, removing one or two panels and replacing them with new ones (straight off the production line) – i.e. replacing all parts that compromise structural integrity – sounds way easier and cheaper than having to introduce a compromise in structural integrity in order to remove a damaged structure.”

        To—
        “Until the first time they need to fix a larger area that’s damaged, we won’t know for sure how much difference their panel approach makes with regard to repair jobs.”

        You probably know, the A350 doesn’t have a “traditional aluminium frame,” but a carbon fibre frame. Sections of each rib are attached to their respective panels with metal brackets & fasteners prior to assembly into barrels; it’s a process akin to traditional metal aircraft panel construction.

        And, of course we “won’t know for sure” how big the damaged area is on the B787’s rear crown and can’t judge the effects on its repair compared to a hypothetical similar repair on an A350-900. imho, there must be a significant amount of damage to warrant the removal of an entire 16 to 18 meter long panel in an A350 in a repair job. Each case judged on total cost.

        But, it is an interesting subject,
        See, Fig. 11
        http://www.compositesworld.com/articles/2011-international-paris-air-show
        And,
        http://www.compositesworld.com/articles/2012-jec-europe-highlights
        and,
        http://www.a350xwb.com/advanced/fuselage/

  5. Airbus should not IMHO be chasing the higher trust ratings for an A350-1100X that would be required for a straight stretch and an increased MTOW to say, some 330 metric tonnes.

    In short, an A350-1100X — or A350-1200X if a shorter A350-1100X version would be the ULR-version à la the 777-8X – could get a modified wing à la the A346-wing that would have a 1.27m long chord-wise tapered wing insert corresponding to 2 fuselage frames; and in addition, two 4m foldable wingtips à la the 777-9X that would ensure that the A350-1200X would be about as optimised as the A350-900 (i.e. runway, climb and cruise performance etc.) if the MTOW of the A350-1100X/-1200X would be around 330 metric tonnes.

    Hence, a larger wing would allow for a lower thrust rating. With a thrust level requirement as low as 93,000 lbs, any new engine developments à la the RB3039 conceptual engine for a stretched A350-1100/-1200, would therefore allow the A350-series to use the same basic engine for a new A350-1100X/-1200X family and a re-engined A350-900 and A350-1000 (i.e. with the dash 1000 having its MTOW reduced by say, 15 tonnes thanks tothe lower weight of fuel carried due to the more efficient engine etc.).

    The main problem though for an A350-1200X — again, assuming that an A350-1100X would be the ULR Version, could possibly be the landing gear footprint. The distance between the centre line of the nose gear and the MLG would be around 36m for a 10 frame stretched A350-1200X (i.e. over that of the A350-1000), while it should be around 33m for the 777-9X.

  6. Hard to believe that ET-AOP could get away with purely bonded repairs. The repair manual shows supplemental bolted splices for much smaller patches.

  7. I have modeled an -1100 at A.net that would make sense. Y type winglets would keep the engines at 100klbf and still have the V2 speed within kts of the -1000. With a natural TSFC evolution of -3% a 320t MTOW variant would fly 400 pax 8300nm.

    • Only 11 tonnes of MTOW growth over that of the A350-1000?

      Anyway, what about modeling an A350-1200X incorporating a larger wing with increased area and span (folding wingtips)? 🙂

      I’m thinking about a 2 frame increase in the centre wing box: From 8 frames to 10 frames; or 5.08m to 6.35m. In contrast, the A340-600 incorporated a three frame stretch in its centre wing box in comparison to the baseline centre wing box of the A340-300; or 5.35m to 6.96m.

      Then, 4 frames added ahead of the wing and 4 frames added aft of the wing, for a total of 10 frames, or 6.35m.

      The wing should retain the leading and trailing edges of the A350-1000, while incorporating 2 folding wing tips (i.e. 3.5-4m). MTOW around 330 metric tonnes.

      Rgds.

      • Yes, since then I have tuned a little bit. I kept the engines the same as for the -1000, just a natural tuned variant spinning a little faster for 100klbf (up 3% which is doable) and put the OEW at 160t, which is not being conservative. The wing needs a good wingtip (Y model) and a re-stress, then it should be fine also for 320t, wingloading is then still below the -9X (which is a fresh design on the wing side). Fuel is fine, max fuel break is at 8800nm and as said start OEI performance is still in the -1000 bracket, Evrard also said MLG is fine for another 10-20 tonnes or so, so not drama there as well.

        Re -1200X, why go to all this hazzle when it would not be needed? The strategic move is to block the -9X if sales shows there is a market, not surpass it.

      • It still looks a bit marginal to me if you want to preserve payload/range compared to the A350-1000. You’re increasing OEW seemingly by only some 6-7 tonnes over that of the A350-1000, yet MTOW is increased by only 11 tonnes?

        For example, the 777-300 has about the same MTOW as the 777-200ER, yet the OEW of the latter is 22.4 tonnes heavier than the former. The 777-300 is stretched by 19 frames over that of the 777-200ER; or 10.17m (19 * 0.535m). If an A350-1100 is stretched by 9 frames over that of the A350-1000; or 5.72m (9 * 0.635m); then in a zeroth-order approximation if the 777-300 had only been stretched by the same increase in length as that of an A350-1100 over that of the A350-1000; namely 5.72m; the OEW increase would have been 14,6 tonnes and not 22.4 tonnes for the “shorter” 777-300 (or 777-250X). Of course, the wetted area is less on the A350 and it uses CFRP, etc, but is that enough to provide for an OEW increase of only 6-7 tonnes, when you also increase MTOW?

        For sure, 100,000 lbs of thrust should be doable, but what about TSFC?

        Now, why should Airbus go through all the hassle of developing an A350-1100 and only use an engine derived from the TXWB-97 and not the new RB3039 coming online in the early 2020s? 😉

        By developing a larger wing that’s based on the one on the A350-1000 and one that’s having about the same span as that of the 777-9X, MTO levels should be able to be reduced down to the original level set for the TXWB-93 on the initial version of the A350-1000. Hence, this new engine, based on e.g. the RB3039, could be used on a re-engined A350-900 as well and in a de-rated version. That’s IMO a smart strategic move.

        As for going through the hassle of developing a new larger wing based on the the one on the A350-1000, please do note that although the method would be similar to how the A340-500/-600 wing was derived from the one on the A340-300, there are many things that would not be similar. For example, the MTOWs of the A345/A346 were around 100 tonnes higher than what was the case on the A340-300; while for the A350-1200 as described above, the MTOW would only be some 20-25 tonnes higher. The weight of the Trent-500 engines was much higher than the “hair dryers” on the A343; while a new engine developed based on the RB3039 concept would weigh less than than the TXWB-97 engine ( etc., etc.). Hence, the new wing would be much lighter, relatively speaking, than the one on the A345/A346.

        When developing an all new wing, AFAIK the movable surfaces accounts for around 70 percent of the development costs. On an A350-1200, the movable surfaces would be retained from the A350-1000. Only the wing box would be “new”; that’s everything located between the front and the aft spars including new larger one-piece wing covers combined with new folding wing tips.

        There’s a good description of the changes required for the A345/A346 in the following link:

        http://www.flightglobal.com/blogs/flightblogger/2012/01/a_closer_look_transitioning_to/

        An A350-1100 (or -1200 depending on whether or not a direct 777-8X rival aircraft would be developed), would have some 50 LD3 positions.

      • Why use the 20 year old 777-200 to -300 stretch for understanding the OEW increase of my -1000 to -1100, there is a perfectly analogous CFRP stretch who flew first flight one month ago, the 787-9, It is a straight 6m stretch with no changes to wing, engines and minor to MLG increasing pax count with 40, OEW goes from 119t to 126t = 7t. Given that the -1000 most likely comes in under 153t an assumed 160t is conservative.

        Re TSFC I have modeled 0.50 which is a 4% improvement over the 93k version by 2022 which is more then reasonable, you gain a bit less then a % per year on a derivative. RB 3039 is not EIS ready in 2022, a demonstrator is what might have.

        Re the -1200 you seem to propose change for the sake of it, the aim of the -1100 study is to block the -9X at it’s sales period ie 2020 or close thereafter. The modeled -1100 would consume 90t fuel over a 7000nm trip where the -9X would require 99t, what do you need more? And it would be a simpler project then the -900 to -1000, no wing, engine or MLG change, only the fuselage + wingtip and a natural evolution of the 97k engine? It is a no brainer and will out-cuckoo the -800 project.

      • As you increase the fuselage fineness ratio, you increase fuselage bending moment and thereby increasing weight; and that function is not linear. Hence, the increased longitudinal tension and compression loads on an A350-1100 over that of the 787-9 vs. the 787-8 would not be the same. At the fuselage lengths we’re talking about, the 777 cross-section is better than the A350 if you want to minimise structural weight-gain for a stretch. CFRP works very well in tension, less so in compression.

        As for TSFC, the “one-percent-improvement per year” back-of-the-envelope rule is for an all new engine, not derivatives. For example, how much has the TSFC of the Trent-700 improved since its EIS in 1995?

        As for an A350-1200X; no, I’m proposing changes for the sake of it. Far from it. I just don’t subscribe to the assertion that a 5.72m stretch of the A350-1000, using the same diameter engines, would only have a MTOW increase of 11 tonnes while maintaining payload/range from that of the A350-1000. Interestingly enough, Scott is also talking about 104,000 lbs. That sounds more reasonable to me, and which would imply a MTOW hike to around 330,000 metric tonnes. For reasons already explained, IMHO the right course should be to pursue lower thrust levels by using a wing at least as large as that of the 777-9X. Then, by using a RR engine derived from the one originally proposed for the 777X, the A350-900/-1000 could be re-engined as well with a lighter and significantly more capable engine a decade or so after EIS of the A359.

        Also, the new wing would allow for growth. Not on an A350-derivative, but on a intermediate ranged, A380-derived twin. Should be doable. As a starter, the A350 and the A380 share the same fuselage frame spacing of 25 inches, or 0.635m. 🙂

      • We don’t know how much Airbus have allowed for an extra stretch in the A3500-1000 re-design, I have always thought that, given the amount of redesign that went into the “1000” a double stretch was always planned, if the market was right.

    • Thank ferpe and OV-099 – this has made for very interesting reading.

      Why I think I tend more toward the ‘ferpe’ line is because I don’t think that Airbus need the ‘best’ solution just something ‘better’ than its competitor (ie. 777-9x).

      ROI is key: how much extra return will a larger wing, new engine etc. actually bring to justify the extra investment?

  8. Re: 787 repair,

    The authorities do not accept bonded repairs absorbing loads as far as I know, because the resulting strenght of those repairs proved far to unpredictable during continuing extensive testing and research.

    So whatever Boeing does w’ll probably see lots of bolts, titanium, plates. From the photo’s I saw at least two sections and their interfaces are deeply damaged.

  9. If Boeing used a similar fuselage from the 731 to the 753, and Airbus went from the A310 to the A346, the A350 fuse has a lot of potential, that is for sure.

  10. Looks like the 787 will top out at the -10. On the other side, they could make a 52m long model with a new 52m code D wing. New engines and all would be a 5 billion dollar program, not cheap but in the realm of possibility.

  11. Recall Airbus Marketing chief, John Leahy said this about the 777X earlier this month at ISTAT– “We don’t respond to paper aircraft.”

    How would he respond to the A350 chief’s, Didier Evrard, comments on a stretched A350-1000 as a possible counter to the 777X? Would he say, “Didier, you don’t have a story here. Keep quite! We don’t respond to paper aircraft. Or, do we? Oh, but we might stretch it, we are not sure how big the market is. We are studying it. But, you don’t have a story here.”

    Pretty slick marketing ploys.

    • Dubai airshow is ahead that will potentially firm a 777x offer.
      Maybe expect an Airbus reaction soon after ( to a less papery proposition ) ?

    • Recall Airbus Marketing chief, John Leahy said this about the 777X earlier this month at ISTAT– “We don’t respond to paper aircraft.”

      Seems he picked up a rhetoric cue from Boeing there 😉
      “During the 2Q10 earnings call today, Jim McNerney, corporate CEO, said, “I wouldn’t characterize [the A350] as a paper airplane, but it’s pretty close to that. I think we will have clarity in a year or so.”
      This was late July 2010, i.e. less than two years before first flight. Not a few weeks before the A350 was even formally launched.
      http://leehamnews.wordpress.com/2010/07/27/boeing-wide-open-on-777-future-albaugh/

  12. I think the A350 is probably easier to repair then a 787. On the former I expect you would remove the relevant panels, then cut away all damaged structure under it, restoring the load carrying frames and put new panels over it. Just like on a metal aircraft.

    On the 787 everything is baked together. So they’ll cut away the plating and attached structure at ones. Then there’s the heavy interface in between the two damaged sections. I hope this isn’t overheated / burned..
    http://jto.s3.amazonaws.com/wp-content/uploads/2013/07/nb20130714a2a.jpg
    Then they’ll probably produce 2 sections identical to the ones cut away on the two sections. And place it in the holes. Producing these two 1 off fuselage assemblies will take a large amount of hands, unique tooling and time.

    The most complicated part is probably fixing it too and making them integral parts of the sections again. Lots of bolts and small titanium plates I guess. You can’t glue them. Gluing is only for filling the holes, making it airtight. If you glue, you are basically fixing the outer laminate layer to something & delamination is around the corner. The authorities will never approve. They have been balking on composites bonded repairs for over 25 yrs for a reason. Test results show enormous variations in strength of bonded repairs. And the FAA hasn’t become more ambitious after the delegated 787 Li-Ion certification, that others are now evaluating.

    Last month there was a Boeing workshop on the repairs topic in Europe. That seems to have raised as least as many question marks as answers.

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