noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Feb 24, 2013 17:24:41 GMT 1
Hi
In my ignorance, I am surprised that the testing performed on the 'fatigue test frame' didn't find the wing crack problem. The information I have is that the frame and test environment were meant to simulate a significant life cycle of a 'real' plane. Were the wings different? Were the tests inadequate? Did the cracks appear but were not spotted? I am surprised that there (appears to be) no reference to the fatigue testing, which ideally would have pre-empted the issue. Raises the question - what is the point of fatigue testing if it doesn't flag issues?
As I say, a question based on my interest, but clouded by my ignorance
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Feb 24, 2013 17:47:56 GMT 1
I suppose that no testing programme is fail-proof (see 787)!
I read that recent simulation software could have predicted the issue, but this software did not exist back when the aircrat was introduced. I cannot guarantee that this is true, though.
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Post by FabienA380 on Feb 25, 2013 0:01:21 GMT 1
I think most likely what happened is that, required tests for new planes would go up to a certain point or time-long, but could not of course equal/exceed the life time of a plane, and the cracks would then have appeared way farther than the legal required test cycles,....... Fabien
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Feb 25, 2013 1:41:07 GMT 1
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Feb 25, 2013 19:51:23 GMT 1
I think most likely what happened is that, required tests for new planes would go up to a certain point or time-long, but could not of course equal/exceed the life time of a plane, and the cracks would then have appeared way farther than the legal required test cycles,....... Fabien The fatigue testing lasted 26 months and accumulated a total of 47,500 flight cycles: 2.5 times the number of flights that an A380 would make in 25 years of operations. Like philidor said: testing is not fail-safe, their are so many variables.
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Post by airboche on Feb 26, 2013 15:56:10 GMT 1
I think they could not exactly predict the fatigue caused by different temperatures. The hot-cold-cycles seem to stress especially parts that got built from different materials. Today they seem to be able to better simulate stuff like this.
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Post by airny on Feb 26, 2013 16:18:35 GMT 1
I have also learned that the hot-cold-cycling has largely attributed to the wing cracks.
Remember it is minus 55 °C up there... So the only option is to simulate/analyse this with software, rather than testing this on the fatique test frame.
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Feb 27, 2013 13:48:13 GMT 1
I have also learned that the hot-cold-cycling has largely attributed to the wing cracks. Remember it is minus 55 °C up there... So the only option is to simulate/analyse this with software, rather than testing this on the fatique test frame. I suppose it's a case of the manufacturers believing they have covered all bases. What it does mean (I assume) is that the purpose of fatigue testing becomes more defined. Things will never be perfect, but the airline industry is getting damned near. All the time there are (hopefully relatively minor) anomalies, then complacency won't creep in.
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Feb 27, 2013 13:50:49 GMT 1
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noistar
Final Assembly Line stage 2
Posts: 388
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Post by noistar on Mar 3, 2013 13:50:43 GMT 1
am I right in thinking that the issue was more to do with manufacturing technique than a fault per-se?
In which case would any software testing have detected it?
I assume the technique wouldn't have been questioned otherwise the problem would never have been there in the first place
Assuming I'm correct in the reason for the fault
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