31–40 of 69 posts
Earlier quoted context omitted.
Apparently A350 are built with Teijin Tenax thermoplastic carbon. Brochures say it cures in one minute, eliminating autoclave. Could be different from normal resin based carbons.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Earlier quoted context omitted.
This has no bearing on this article, it is not about fatigue but about surface defects, not structural defects.
The mention of cracks was coming from this post: "A QR A350, A7-ALL MSN 036, a 4 year A350, was being prepped for paint removal from the standard QR livery and repaint into the Qatari World Cup 2022 livery at SNN when IAC engineering discovered that the airframe had premature cracks in the composite fuselage..." https://www.airliners.net/forum/viewtopic.php?f=3&t=1456315&... I am aware of Airbus statement that is onl…
If they were comfortable flying it that should tell you something.
This seems like the first time they’ve encountered the phenomenon so they want to do a deeper investigation to understand it.
This whole thread is akin to saying that if you have to debug your code it must be beyond repair or poorly designed.
Earlier quoted context omitted.
Apparently A350 are built with Teijin Tenax thermoplastic carbon. Brochures say it cures in one minute, eliminating autoclave. Could be different from normal resin based carbons.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Earlier quoted context omitted.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Why would you think that? You think these aerospace engineers are a bunch of goof offs?
Aerospace engineers are anything but a bunch of goof offs, which is why flying is as safe as it is. And that's why they pulled the aircraft from service even though it is 'just a surface issue' they want to make sure that it really is just that before releasing them - freshly painted - back into service again.
The history of aerospace quality control is written in blood, not because they are goof offs but because materials science is complex and sometimes the only warning you get that something is wrong is a crash. Avoiding those is what this sort of action is all about, in any other industry they would have slapped some new paint on it and kept going.
Earlier quoted context omitted.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Is the paint for anything more than cosmetics/branding purposes? Does it provide a benefit like UV shielding etc? In otherwords, do we use the paint for anything other than ego of corps owning them?
https://www.skybrary.aero/index.php/Surface_Coatings_and_Dra...
Then there is corrosion protection, protection from ablation (especially on leading edges which usually have other protection against this as well), ice adherence and so on. So it is far from just cosmetic, and given the weight of a single coat of paint (500+ pounds on a 777 for instance) airlines make sure they optimize for fuel consumption because just hauling 500+ pounds along for the lifetime of the aircraft costs a pretty penny.
Aircraft are fairly regularly stripped and re-painted too (I lived near a special purpose facility in Canada that did this, pretty weird to see a widebody come down in a location that is not near any major airfield, the first time I saw that I thought it was about to crash, but it turned out it was there for a paint job).
I've been a long time carbon-fiber skeptic. Only an armchair materials enthusiast but carbon fiber construction seems to lack the margin for fatigue that aluminum has. It seems to me that when carbon fails it fails catastrophically, while aluminum allows some "give". Now it seems carbon fiber doesn't have the longevity either? I am aware the aluminum can "work harden" over time and become more brittle as well. No mat…
If anyone is curious about material science, some keywords are "stress strain curve", "plastic vs elastic deformation", and "fatigue limit" (that last one is really cool).
Earlier quoted context omitted.
Apparently A350 are built with Teijin Tenax thermoplastic carbon. Brochures say it cures in one minute, eliminating autoclave. Could be different from normal resin based carbons.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Earlier quoted context omitted.
This has no bearing on this article, it is not about fatigue but about surface defects, not structural defects.
On the assumption these panels are a component of the pressure vessel—and it would seem that they are—then they very much are structural components. Not in "the wing will fall off" kind of way but in "the whole cabin will explosively decompress" way. /Acey
I'm quite interested in what the root cause here is, whether it is process related or some formulation issue or an un-anticipated reaction.
As a -small- point of order it is against HN convention to sign your comments.
Earlier quoted context omitted.
Yes, and quite possibly they did not factor in the long term differences between interaction of paint and materials.
Sounds plausible, if someone told me that this can of paint designed for that epoxy destroys this thermoplastic, I’d just believe it.
I've been a long time carbon-fiber skeptic. Only an armchair materials enthusiast but carbon fiber construction seems to lack the margin for fatigue that aluminum has. It seems to me that when carbon fails it fails catastrophically, while aluminum allows some "give". Now it seems carbon fiber doesn't have the longevity either? I am aware the aluminum can "work harden" over time and become more brittle as well. No mat…
It's way to early to speculate about this, as we don't really have information from either side. The fact that only Qatar Airways seem to have such problems (for now) is also interesting. The reason could be anything from manufacturing errors with a specific batch of them which happened to have been bought by Qatar Airways to wrong maintenance by Qatar Airways or the planes having been to often exposed to to extreme…
That’s not to say that quality issues don’t happen, they certainly do. But QTR is known to be very quick to refuse to work with their supplier and publish the complaint in the press, instead of working it out like is the norm, especially if it’s near a time of contract negotiation.