A380 fails key structural test.

source

The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft.

The airframer has been running load trials on a full scale A380 static test specimen in Toulouse since late 2004 (pictured below). After completing “limit load” tests (ie the maximum loads likely to experienced by the aircraft during normal service), progressively greater loads have been applied to the specimen towards the required 1.5 times the limit load. Engineers develop finite element models (FEM) to calculate the load requirements.

“The failure occurred last Tuesday between 1.45 and 1.5 times the limit load at a point between the inboard and outboard engines,” says Airbus executive vice president engineering Alain Garcia. “This is within 3% of the 1.5 target, which shows the accuracy of the FEM.” He adds that the ultimate load trial is an “extremely severe test during which a wing deflection of 7.4m (24.3ft) was recorded”.

That can’t be good.

Where’s Off-the-Street? I wonder if they’re celebrating this news over at Boeing?


Note the spin from Airbus.

[edit on 17-2-2006 by HowardRoark]

Didn't post the rest of it though...

The European Aviation Safety Agency (EASA) says that the maximum loading conditions are defined in the A380 certification basis. “The aircraft structure is analysed and tested to demonstrate that the structure can withstand the maximum loads, including a factor of safety of 1.5. This process is ongoing and will be completed before type certification.”

However Garcia says that the failure of the wing below the 1.5 target will require “essentially no modifications” to production aircraft: “This static test airframe has the first set of wings built, and we have refined the structural design for subsequent aircraft due to increased weights etc. We will use this calibration of the FEM to prove the adequacy of the structure on production aircraft.”

EASA says that it is aware of the structural failure but "cannot make a statement about the specific failure as it has not been officially briefed by Airbus on what the cause was, and the certification process is ongoing".

Garcia says that the FEM calculations had already established that the A380’s wing had “no margin at ultimate load. We had a weight saving programme and ‘played the game’ to achieve ultimate load.” However in earlier briefings, Airbus structural engineers had stated that it planned to carry out “a residual strength and margin research test” in 2006 after completing ultimate load trials.

The results gleaned from the static testing will be extrapolated for the future aircraft developments over the next 40 to 50 years says Garcia. “It is normal to refine and strengthen the structure of new heavier or longer range variants,” he says.

So despite the prototype wing not working, it has demonstrated the accuracy of their FE modelling for the basic structure, and since the production wing is already stronger, they can do the FE analysis on it to prove it can reach the 1.5 limit and happy days all round.


Boeing won't be singing & dancing over it, but I'm sure there will be a few grins and smirks. Airbus' real problems lie with the wing for the A350 I am led to believe.



edit: Quote tags

[edit on 17-2-2006 by kilcoo316]

Ahh airbus, build it right to the acceptable limit and leave it. Or don't build it to the acceptable limit, and just note it in the operating handbook. Garbage.

[edit on 17-2-2006 by mxboy15u]

Are you crazy Howard??!?!?!?

You know what you have done? You have posted critique of the beloved Airbus!!! Its against the TOS!!!

Thats almost as bad as saying anything against the Vulcan!!!


You may be banned for speaking ill of an Airbus aircraft....

[edit on 17-2-2006 by skippytjc]

I hope that they are going to test a production wing as well and not just take the computer's word for it. I don't know what Airbus's design criteria for this wing is but they need to have one that passes destructive testing. I do 3D design and FEA for a living. We have had a design be within 1% of our model and still fail in service. We destructive test all of our products extensively. This way we know what the computer says is correct (think Pentium floating decimal point), it is helpful in the event of a liability lawsuit and besides its fun.

Give me a 747 any day.... I don't like getting on a new production plane period... let alone a new model.... If there is ever a crash similar to the old British Comet all will point back to that 3%....

Why does Airbus underengineer their airframes? Is it to meet their projected weight goals? Every time I fly, and I see I am on some Airbus product, I get just a bit more nervous...

Well, to me it doesn't matter if it will ever reach this "dangerous" level... It hs still been prooven weak... And that is not good news...

You people jump to conclusions. Their target for overstrength was a factor of 1.5 The test reached 1.47. Id say thats pretty damn good. The 1.5 was a mathematical calc and depending on loading conditions etc, it seems like they did a pretty dam good job.

If you actually read the article, you would also know that the deflection at failure was 24 feet off horizontal!!!!!! The most ive ever seen a wing deflect when i was in a place was MAYBE a foot.

Train

Originally posted by BigTrain
You people jump to conclusions. Their target for overstrength was a factor of 1.5 The test reached 1.47. Id say thats pretty damn good. The 1.5 was a mathematical calc and depending on loading conditions etc, it seems like they did a pretty dam good job.

If you actually read the article, you would also know that the deflection at failure was 24 feet off horizontal!!!!!! The most ive ever seen a wing deflect when i was in a place was MAYBE a foot.

Train

Its worth remembering that the a380 has a much greater wingspan than anything that only deflects a foot. Having said that, 147% in actual test conditions with continuous stress is pretty damn good considering the 150% target.

The real concern should be that 20 years from now all these semi-composite planes may have developed structural deficiencies that are not easy to spot in routine inspections. We should hope they have or are developing new processes for inspecting composite aircraft. Given past failures of composite components in civilian aircraft it should be apparent current procedures are not sufficient.

Yes train, despite Skippy's cutting sarcasm (although slagging off the Vulcan should be a hanging offence) it seems more like the opposite is true and any kind of negative news about Airbus is grasped joyfully by a section on here.

The wing didn't fail short of its max load, which is what seems to be assumed, but at nearly 1.5 times is overload, that is why this is not a safety issue. If it were dangerous Airbus would not risk its future existance on just ignoring the problem.

It’s not going to be as easy for Airbust to overcome this issue as some may think. The A380 is already overweight and behind schedule. This won’t help sales.

No comment from Boeing about the A380 wing test, but they seem more interested in pushing thier 747-8, a dreamliner influenced 747.

Both the passenger and freighter versions of the 747-8 will allow operators to maximize their profitability. Seat-mile costs for the 747-8 Intercontinental are 8 percent lower than the 747-400, with comparable trip costs. The 747-8 Intercontinental is more than 13 percent lighter per seat than the A380, and as consumes 14 percent less fuel per passenger. That translates into a trip-cost reduction of 22 percent and a seat-mile cost reduction of more than 6 percent compared to the A380.

Frequent mentions towards the end of the article of the A380, with the apparent aim of grabbing more of the market share.

It's my understanding that Boeing has a tradition of over-engineering thier wings, which if true, could mean we might see Boing do some destructive testing of the 747-8 wings purely for publicity reasons. (but only if they're confident they can make the wingtips touch )

[edit on 17-2-2006 by Travellar]

Let me see which one would I rather fly in...untested technology that was really close to meeting expectations...or an overengineered proven design.

Originally posted by mxboy15u
Let me see which one would I rather fly in...untested technology that was really close to meeting expectations...or an overengineered proven design.

The normal 747 is a lovely aircraft and can certainly be considered a proven design but the 747-8 is certainly not a proven design. Its as experiemental as any other aircraft made from some of the newer, lighter materials.

Originally posted by mxboy15u
Let me see which one would I rather fly in...untested technology that was really close to meeting expectations...or an overengineered proven design.

Well what do thing they are doing the test part now? The test part , perhaps. Just like boeing will Have to do etc.

Over engineered, the actual phrase, does not mean, stronger it refers to "over complicate".
example for doing basic math(+,-,X division) a pencil and paper is is fine. using a computer to multiply 2 x8 is over engineering it.

Lets put that load test in perspective. THe 100% test was full passengers, full baggage and cargo, full fuel, all the bags of peanuts and pop, tiolet fluid etc. and then they added 47% more weigth and hung that weight from the wing tips. For a proof of concept wing it was a good show.

It will not carry paying customers before they (any airplane) has satisfied all the tests kiddo, do not woorry.

Mind you so did the comet


Dead steve

[edit on 17-2-2006 by dead steve]

did any of you ever hear about the Gimli Glider?

Six miles out Pearson began his final approach onto what was formerly RCAFB Gimli. Pearson says his attention was totally concentrated on the airspeed indicator from this point on. Approaching runway 32L he realized he was too high and too fast, and slowed to 180 knots. Lacking divebrakes, he did what any sailplane pilot would do: He crossed the controls and threw the 767 into a vicious sideslip. Slips are normally avoided on commercial flights because of the the tremendous buffeting it creates, unnerving passengers. As he put the plane into a slip some of Flight 143's passengers ended up looking at nothing but blue sky, the others straight down at a golf course. Says Quintal, "It was an odd feeling. The left wing was down, so I was up compared to Bob. I sort of looked down at him, not sideways anymore."

The Gimli Glider

The only problem was that the slip further slowed the RAT, costing Pearson precious hydraulic pressure. Would he be able to wrestle the 767's dipped wing up before the plane struck the ground? Trees and golfers were visible out the starboard side passengers' windows as the 767 hurtled toward the threshold at 180 knots, 30-50 knots faster than normal. The RAT didn't supply "juice" to the 767's flaps or slats so the landing was going to be hot. Pearson didn't recover from the slip until the very last moment. A passenger reportedly said "Christ, I can almost see what clubs they are using." Copilot Quintal suspected Pearson hadn't seen the guardrail and the multitude of people and cars down the runway. But at this point it was too late to say anything. A glider only gets one chance at a landing,and they were committed. Quintal bit his lip and remained silent.

I read the book that was written about this event Freefall (Paperback) and when Boeing was asked about this, they even said that the forces that were put on the plane in this severe of a side slip were never considered as it was never expected to perform this maneuver.


here's a video of the news worthy event

'Gimli Glider' lands without fuel


an interesting fact is that an avreage plane touches down about 1000 feet from the threshold. This pilot touched down just 800 feet from the threshold

Pearson had touched down 800 feet from the threshold and used a mere 3000 feet of runway to stop. A general aviation pilot who viewed the landing from a Cessna on the apron of 32R described it as "Impeccable." The 767 was relatively undamaged.

so I'll fly a Boeing any day. when it comes to expecting more from a plane than you thought it would do they come through

[edit on 17-2-2006 by bigx01]

Well as a passenger it makes no difference at all whether I fly on a Boeing or an Airbus, they are both well proven and popular makes of Airliner.

Now if I saw a DC-10 waiting for me I might go and look up the train timetable pretty sharpish

If you're refering to the Chicago crash of a DC10 then you should be aware that it was not a design flaw but airline negligence in using a fork lift to replace the engine that caused the engine to break loose and come off.

and you should remember that the St. Louis crash was the result of a catastrophic engine failure that severed all hydraulic lines, including the 2 redundant systems, not a design flaw in the plane.

Ah yes, but that doesn't stop you having a go at Airbus where there is also not a design flaw, see the double standard here? You see I knew someone would leap to the defence of the DC-10 and lo and behold if it isn't one of the very members thats having a go at Airbus and with far less reason. But hey, I'm just a sneaky European