Thursday, April 06, 2006

Certification Snag for Airbus Wingset

An interesting article today in the Telegraph. It's ostensibly a discussion of a couple of Airbus stockholders thinking about selling off their shares. Not altogether a bad deal, as Lagardiere and Daimler Chrysler stand to make some money on the sale.

But wait.

The article makes the connection with the test wing failure below the 1.50 ultimate load figure mandated by regulatory authorities. You remember how the wing failed at 1.45 of ultimate load and the Airbus PR machine told us not to worry, alles in ordnung and all that, it's be taken care of.

Well, according to this report it wasn't. That's bad.

What's worse is the fact that this wingset was a pair that were heavier prototype assemblies that were around before Airbus, knowing what we here at The Dougloid Papers have previously figured out on paper using published sources about the weight problems facing the A380, decided it was time to cut some weight out of the production wings-one per cent, to be exact.

Whether this affects the outcome of the ultimate load tests yet to be accomplished is unknown but it certainly cannot be classified as unalloyed good news. Airbus has responded by saying that the wingset was a test article that had already been through a lot. That could well be. If so, all the more reason to retest with a production wingset.

Airbus has three choices here.

Bite the bullet, beef up the wingset, and retest, with all the heartache and delay that will bring.

Show by substantiation that the production article will meet the requirement.

Reduce the allowable weights on the wingsets that are through build, and by a combination of substantiation and service bulletins, bring the earlier aircraft into compliance.

Anyway it is sliced, it's a piece of bad news of the kind that Airbus doesn't need more of just now with the A380 program.

McDonnell Douglas had to try it twice before they got the C17 Globemaster wings through the test-it isn't the end of the world for Airbus, but the risk is that the customers may think it is. The problem with the C17 wingset was not, however, in the design, but in the execution. The test items were just not well built enough to meet the design objectives, and there were a lot of fastener holes that were not straight and normal to the material. That was cured and things went along swimmingly after that.

I saw the C17 test rig, and it was a ferocious setup that took up all of a large building. I was informed that when the first set let go, it was with the sound of a moderately sized field gun going off-it shook windows in nearby offices. One can only speculate what the ultimate load test sounded like on the A380 wingset was like.


At 4:43 AM, Blogger G. F. McDowell said...

Man, if it's like you say, this thing is going to flop like the tristar, only without a DC-10 to compete it out of existence.


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