Texfly101 From United States of America, joined Jan 2006, 351 posts, RR: 0 Posted (6 years 3 weeks 2 days 6 hours ago) and read 8681 times:
Pardon me if this has been discussed in a prior post, but I searched and didn't see it in a Topic line. But this has been of so much interest to a lot of people on this site, I thought I would add it. In AvWeek, 5/01/2006, the following statement appeared in an article about the A350 redesign. I'm not making any challenges or conclusions, only passing along info.
"Meanwhile, Humbert says the company has determined that wing design changes will not have to be made on the A380, after a test specimen narrowly failed to meet the ultimate loads limit. An in-depth analysis has shown that the wing in question had been subject to loads in excess of the ultimate load targets ahead of the official test. Airbus found the structure was damaged in the earlier test so that it could not hold up a second time to the specified breaking point. Airbus also does not need to repeat the test, Humbert adds, because the manufacturer can demonstrate the premature rupture was caused by the earlier damage."
AirFrnt From United States of America, joined Jul 2004, 2748 posts, RR: 45 Reply 1, posted (6 years 3 weeks 2 days 6 hours ago) and read 8648 times:
Quoting Texfly101 (Thread starter):
"Meanwhile, Humbert says the company has determined that wing design changes will not have to be made on the A380, after a test specimen narrowly failed to meet the ultimate loads limit. An in-depth analysis has shown that the wing in question had been subject to loads in excess of the ultimate load targets ahead of the official test. Airbus found the structure was damaged in the earlier test so that it could not hold up a second time to the specified breaking point. Airbus also does not need to repeat the test, Humbert adds, because the manufacturer can demonstrate the premature rupture was caused by the earlier damage."
We will see what the EU and the FAA think of that. Last I heard the FAA wasn't buying that answer.
Ikramerica From United States of America, joined exactly 7 years ago today! , 20630 posts, RR: 62 Reply 2, posted (6 years 3 weeks 2 days 6 hours ago) and read 8612 times:
That's good news as to why it failed. It is very reasonable too. But I don't know that the regulating agencies will accept it without another test. While it isn't cheap, sacrificing one more wing to prove it's fine is better than having to make modifications to all the wings and future wings in the pipeline, right?
Hopefully the agencies will accept the calculations since it was very close.
Of all the things to worry about... the Wookie has no pants.
B777LR From United States of America, joined May 2006, 13 posts, RR: 0 Reply 4, posted (6 years 3 weeks 2 days 5 hours ago) and read 8461 times:
If Airbus is pleased with the wing and it meets their requirements that is great. Though I do have to point out that this may have some after effects for the futuer growth of the aircraft. The 900 model may need some more extensive refinements done to the wing down the road when they increase the MTOW. I just hope they are not rushing to get the airplane into service.
Artsyman From United States of America, joined Feb 2001, 4740 posts, RR: 53 Reply 8, posted (6 years 3 weeks 2 days ago) and read 8146 times:
In the day of the lawsuit hungry human, the FAA cannot just accept the word of Airbus that the wing, despite failing the test is actually fine. All it will take a wing to fail inflight, killing everyone onboard and the FAA being sued for allowing Airbus to skip the certification process...
MD88Captain From United States of America, joined Nov 2001, 1258 posts, RR: 24 Reply 10, posted (6 years 3 weeks 1 day 17 hours ago) and read 7809 times:
Sorry. Your mistake. Repeat the test. Eat the cost of your mistake. Comply with the requirements that you knew were in existance before you designed the thing.
OldAeroGuy From United States of America, joined Dec 2004, 3141 posts, RR: 66 Reply 11, posted (6 years 3 weeks 1 day 16 hours ago) and read 7654 times:
Quoting Antiuser (Reply 3): Maybe they'll be able to certify it by analysis, didn't GE do that with the GE90 after it failed a blade-out test?
No, they re-ran the test.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
RichardPrice From , joined Dec 1969, posts, RR: Reply 12, posted (6 years 3 weeks 1 day 16 hours ago) and read 7577 times:
Quoting B777LR (Reply 4): Though I do have to point out that this may have some after effects for the futuer growth of the aircraft. The 900 model may need some more extensive refinements done to the wing down the road when they increase the MTOW. I just hope they are not rushing to get the airplane into service.
The A380-900 will use the A380F wing, which has been altered for a higher MTOW iirc.
Dazeflight From Germany, joined Jun 1999, 552 posts, RR: 3 Reply 13, posted (6 years 3 weeks 1 day 15 hours ago) and read 7539 times:
Quoting MD88Captain (Reply 10): Sorry. Your mistake. Repeat the test. Eat the cost of your mistake. Comply with the requirements that you knew were in existance before you designed the thing.
They are surely lucky that you got nothing to say when it comes to certification
RichardPrice From , joined Dec 1969, posts, RR: Reply 16, posted (6 years 3 weeks 1 day 14 hours ago) and read 6971 times:
Quoting Halls120 (Reply 15): More importantly, why did they use a wing section they knew had been damaged for this all-important test?
It may have not been apparent until after all the data had been collected and analysed from the entire testing regime that the wing had exceeded the limits earlier on, it may have occured in a test where that load wasnt the primary resultset and thus wasnt looked at in much depth until after the wings failure later on.
Poitin From , joined Dec 1969, posts, RR: Reply 17, posted (6 years 3 weeks 1 day 14 hours ago) and read 6761 times:
Quoting Artsyman (Reply 8): In the day of the lawsuit hungry human, the FAA cannot just accept the word of Airbus that the wing, despite failing the test is actually fine. All it will take a wing to fail inflight, killing everyone onboard and the FAA being sued for allowing Airbus to skip the certification process...
While the FAA can't be sued (they are part of the government), the airline that bought the plane can. As can Airbus. And, of course, the FAA would have to answer to Congress. So, basically, the FAA will cover their butts and say "break it!"
Quoting Halls120 (Reply 15): Quoting Zvezda (Reply 7):
Why on earth would Airbus overstress a wing that they knew would later be used for certification testing? It makes no sense.
More importantly, why did they use a wing section they knew had been damaged for this all-important test?
Let's assume that this is actually what happened and someone goofed. Now what does that say about Airbus's management? More important, what would the wolf pack of lawyers do with that in court of law?
This is a VERY bad situation for Airbus. They need to sort this out. Their best solution is to break another wing, one that is used on the production aircraft. $50 million is cheap compared to what could happen in a law suit.
RichardPrice From , joined Dec 1969, posts, RR: Reply 18, posted (6 years 3 weeks 1 day 14 hours ago) and read 6761 times:
Quoting Poitin (Reply 17): While the FAA can't be sued (they are part of the government), the airline that bought the plane can. As can Airbus. And, of course, the FAA would have to answer to Congress. So, basically, the FAA will cover their butts and say "break it!"
The FAA can be sued, they just have to give you permission to go ahead first Same with most US governmental branches, but not all.
Poitin From , joined Dec 1969, posts, RR: Reply 19, posted (6 years 3 weeks 1 day 14 hours ago) and read 6636 times:
Quoting RichardPrice (Reply 18): The FAA can be sued, they just have to give you permission to go ahead first Smile Same with most US governmental branches, but not all.
And of course, they will give you permission, which is why I said you can't sue.
Lightsaber From United States of America, joined Jan 2005, 8531 posts, RR: 100 Reply 20, posted (6 years 3 weeks 1 day 14 hours ago) and read 6601 times:
Quoting OldAeroGuy (Reply 11): Quoting Antiuser (Reply 3):
Maybe they'll be able to certify it by analysis, didn't GE do that with the GE90 after it failed a blade-out test?
No, they re-ran the test.
And GE failed the 2nd test. But that gave them enough data to certify by analysis. I have a great photo on the 2nd blade out test where you can see matter leaving the engine radially which is forbidden. Click on the thumbnail for a better view. This was the screensaver of choice cica 1999 at Pratt.
Does anyone have a link to any FAA comments? I'd rather not guess as to which way they're going on this important issue. Its possible the FAA, after reviewing test data will accept Airbus' analysis. However, its also possible that they will go the other way... Just hope the decision isn't made by some old codger who was the intern on the Lockheed Electra when it had wing failurs! Seriously, how the FAA goes in a decision is unfortunately sometimes driven by the personality of the committee selected for review.
Halls120 From , joined Dec 1969, posts, RR: Reply 21, posted (6 years 3 weeks 1 day 14 hours ago) and read 6521 times:
Quoting RichardPrice (Reply 16): Quoting Halls120 (Reply 15):
More importantly, why did they use a wing section they knew had been damaged for this all-important test?
It may have not been apparent until after all the data had been collected and analysed from the entire testing regime that the wing had exceeded the limits earlier on, it may have occured in a test where that load wasnt the primary resultset and thus wasnt looked at in much depth until after the wings failure later on.
Why didn't they use a "fresh" wing for this critical test?
RichardPrice From , joined Dec 1969, posts, RR: Reply 22, posted (6 years 3 weeks 1 day 14 hours ago) and read 6467 times:
Quoting Halls120 (Reply 21): Why didn't they use a "fresh" wing for this critical test?
Because wings cost a lot, Airbus is a for profit company, wings arent available on demand and the wing wasnt supposed to have exceeded the limit before.
Its all well and good people here on a forum saying 'Why didnt they do this ... why didnt they do that ...' but when people talk about millions of dollars, it really is a lot of money even for a large company that routinely deals with these sorts of figures. If they can avoid spending more than they have to, they will.
JayinKitsap From United States of America, joined Nov 2005, 761 posts, RR: 1 Reply 24, posted (6 years 3 weeks 1 day 14 hours ago) and read 6422 times:
I must assume that Airbusses test stand uses computer controlled equipment to properly load each of the many hydraulic cylinders (or actuators) at the various points out on the wing to simulate the distributed pressures on a wing for each test. The wing test is supposed to be at 150% of the maximum wing design load. However, I can imagine there are other tests that are unusual cases that may be at 125% or 133% of design load.
I would expect that each cylinder has pressure limits and each test has specific procedures and programming to test various conditions. Also, there would be a boatload of strain gauges installed that the stress levels would be recorded. In the much more mundane (and much more budget limited) building world, we would know right then in a test that were were up at the strength limits of the structure.
If it was my program and it came to my attention that we have made an excursion over the test limit stresses, I would have logged it, identified this to the agency representative (or independant lab representative) that is witnessing the test what had occurred. When the later test came up, yes it would be performed, but it would have been documented beforehand that the performance would have been degraded somewhat because this portion had failure level loads.
With all of the sophisticated computers that they have, this response sounds like they have been leafing thru reams of trifold computer paper printed by dot matrix printers.
25 Poitin: It looks like it had been "enhanced" by Photoshop. The flames coming out of the rear are fairly real, streaming vigorously, and there is glow reflect
26 RichardPrice: The pictures of the RR Trent 900 testing for the A380 are similiar, with flame and cloud coming out the front. When I get home I shall take a screen
27 787engineer: This may well be true, and the test engineers of course were pressured to re-use the wing that they've been testing all along to save costs. But now
28 Poitin: Are they using an explosive device and how large if so? That could be it, if large enough.
29 A319XFW: See above - cost and availability. But there are a few plausible explanations for the early test specimen failure, but as before - an aviation forum
30 RichardPrice: An explosive bolt iirc, but unless they have a pyromaniac on the team, it should in no way produce the above result. In the RR test you can see the g
31 Widebodyphotog: It's fake, there was no airframe cowling on the engine during the test. Test engines have the large velocity horn mounted. There is no need for anti-
32 RichardPrice: Poitin, here is a quick capture of the Trent 900s bladeoff test.
33 Molykote: The following is by no means perfect or complete but it may get some of you started in realizing how the above photo scenario can happen. I have no k
34 RichardPrice: My comment that you quoted was meant to convey that the blade seperation charge wouldnt have produced the result shown, not that the result shown is
35 Molykote: Understood now. Thanks for the clarification!
36 Lightsaber: I have done nothing to the photo, I've had the file for years and many a Pratt engineer pointed out details on how it was a blade out test. I can't p
37 Lightsaber: Thanks for the photos... First, thanks for the photos. And didn't RR prove by simularity that their nacelles were ok and thus why its tested with the
38 RichardPrice: Out of interest, where can you see a man in the Trent image? Its definately real, it was taken from the 'A380: Worlds Largest Airliner' video from Ch
39 RichardPrice: During the footage you see the side of the engine during the test, it bulges but not even significantly and nothing seperates from the main shroud, s
40 Lightsaber: First, RichardPrice, I owe you an appology. Please read the following to understand why my opinion has changed on your photo... except I would like to
41 Dougloid: It doesn't make any sense ot me either. And if it was my problem to fix, the people who overstressed it before the Trophy Run would be out looking fo
42 RichardPrice: No apologies necessary, really I see what you mean, but if you look to the right you can see something on the stairs which is almost exactly the same.
43 Poitin: I am not saying you did anything, but since it was a popular screen saver at PW, I am still suspicious that someone "made it look better." To wit, th
44 OldAeroGuy: I was referring to the GE90-115B blade out test. The first one failed, the second one passed. I didn't know about the earlier GE90 blade out failure.
45 Widebodyphotog: Sorry I don't have a way of posting it right now but in the video of the GE90 FBO test I have the engine does not have the full flight nacelle mounte
46 RichardPrice: I know, read my clarification in reply 34.
47 Tockeyhockey: it's reasonable that airbus went into the most important wing test in the company's history without knowing that the wing had been damaged in a previ
48 Poitin: While I have no idea about the triple spool engine, there is clearly evidence of oil being burned in both the flame coming out of the back of your po
49 Halls120: LOL, good response. I recognize that people think it might be a silly question, but if I was trying to get my brand new aircraft certified, I would h
50 Okie: That was part of the "Friut of the Loom" containment test. Okie
51 Ken777: I saw the "man" also, but thought it was just distortion from a long lens. then I looked at his "feet", which appear to be a cement block - something
52 Ikramerica: Nice way to divert this thread toward the GE90. Bravo people. Bravo! That's not what I said. I said it's a reasonable explanation for why it doesn't n
53 777WT: Looks like an high speed camera mounted there to watch the fan and the cowling. Look on the opposite side of the photo, there's another one there. In
54 Lightsaber: FYI, blade out is at 103% RPM per FAA requirement. The engine runs at much more than full power. The fuel limiting orifices have to be oversized to a
55 Lumberton: "a while" as in having the potential to delay EIS to SQ?
56 Texfly101: I agree. And maybe its just being the older I am, the more conservative I get as an engineer, but I would want to know that my calcs were proven by a
57 7FTwinOtter: Don’t take my word for it but I think the “man” may be some kind of lighting rig as they use a very high speed film camera to photograph the te
58 Lightsaber: I don't know. All I know is the more you pressure the FAA to go fast, the less you're going to like their answer. I apologize for "hyjacking" this th
59 Ikramerica: Me too. I'll be having lunch at In N Out that day!!!!!
60 Lightsaber: Then I'll be behind you ordering my burger protein style. Lightsaber
61 Atmx2000: I don't think you should feel too bad. I noticed the "man" as well when I looked at the picture and thought to myself I wouldn't want to be where he
62 Jacobin777: oh yah.......you guys can wait..they need to bring the big beast here to SFO first. .......we're already "A380 ready"...
63 Slarty: IIRC, this latest explanation is different than the last one which appeared shortly after the fail ... which attempted to blame the stress failure on
64 Lightsaber: Yea... but all the explanations are coming from managers. Let's get the chief engineer on camera. Then I'll listen more seriously to what's being sai
65 Joni: I think Humbert knows the standards the agencies have for certifying by analysis and he would hardly be saying that they can certify by analysis if i
66 Lumberton: There is firm, final guidance from the certification agencies that they do NOT have to re-do the test? I thought that was still a point of contention
67 Kangar: Pretty impressive if they managed to hit 145% with a damaged set of wings.
68 Joni: I don't recall hearing of any contention on the issue.
69 Lumberton: What then is the point of this thread? Humbert comes out and says they don't have to re-do the test; the certification agencies remain mum. Doesn't s
70 Joni: Many threads on A.net are quite pointless. After the test, Airbus' reps said they likely won't have to redo the test since analysis and if necessary
71 Halls120: So is having to re-test, or redesign, if that is what happens.
72 Lumberton: I think we keep talking past each other here. Until the certification agencies, i.e., EASA and FAA, agree then there is a possibility that the wing t
73 Joni: Well if you want to put it specifically that way. On a similar vein, we could equally state that it's entirely up to the certification agencies if th
74 Lumberton: I don't remember reading where the all-composite fuselage failed a test. Could you please point this out? IIRC, there are aircraft flying with compos
75 Poitin: I thought my point was clear. If they screwed up so badly with this test, what else did they screw up? That is not the question they want to hear in
76 Dougloid: That is what we here in the states call whistling past the graveyard. I'm sure they would like it to be so but the decision isn't up to Airbus what l
77 Dougloid: Well, there IS the FTCA..... http://www.lectlaw.com/def/f071.htm
78 Dougloid: they had a pretty good set of test movies at GE when I went to Lynn for CF34 school, including a blade out....helluva film. Plus some bird strike mov
79 Joni: Your profile claims you reside in Denmark. I didn't claim that the 787 fuselage had failed a test - in fact no 787 fuselages have even been built yet
80 Zvezda: Not true. There are several business jets with composite fuselages already flying. There are also lots of private aircraft with composite fuselages.
82 Poitin: " target=_blank>http://www.lectlaw.com/def/f071.htm Yes, there is the possibility, for, The FTCA provides a limited waiver of the federal government's
83 Areopagus: Where on their website are you looking? I have understood their statements to mean that 50% of the OEW is composites. Non-composite portions include
84 NorCal: Nope they have been built and tests have been conducted http://boeing.com/commercial/787family/gallery/k63374.html http://boeing.com/commercial/787fa
85 Zvezda: Yes, the primary structure of the B787 is overwhelmingly composite. Also, some parts of the engines, brakes, etc. are also composite. Composites have
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But that gave them enough data to certify by analysis. I have a great photo on the 2nd blade out test where you can see matter leaving the engine radially which is forbidden. 
Seriously, how the FAA goes in a decision is unfortunately sometimes driven by the personality of the committee selected for review. 
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