A350 paint degradation problem is getting nasty

[anorlunda]

It seems that there is some problem with the paint on new Airbus A350s. The paint degrades, and the airlines think that the structural composites under the paint are degrading also. The problem could be structural airworthiness related, not just cosmetic.

Qatar has grounded their fleet of 20 A350s. The video says that five other A350 customers have the same complaint. Future orders and future delivery acceptance of A350s are in jeopardy.

Now the nasty part. Airbus is suing its customers about public statements, and the customers are suing Airbus. It is very rare to see a company sue its own customers.

 

[boneh3ad]

Any new tech is going to have teething problems, and planes made largely out of composites are new tech. Having said that, Boeing did it first and so you'd think that the second person to do it would learn a thing or two about what not to do. I guess not.

 

[anorlunda]

Any new tech is going to have teething problems

The first flight of A350 was 2013. That's no longer new tech.

 

[berkeman]

The first flight of A350 was 2013. That's no longer new tech.

When did they start using the new paint? (sorry, no time to watch the video right now...)

 

[boneh3ad]

The first flight of A350 was 2013. That's no longer new tech.

Sure it is. If it's the first model to be made of composites and the material starts showing its age in a way that is concerning after only 8 years, that's still something that can easily be chalked up to new tech. None of these planes had been tested long term yet.

 

[russ_watters]

Admittedly I didn't watch the video, but I'm guessing it could be/airlines think it is fatigue (repetitive stress damage). Fatigue is a time bomb, and I'm not sure it's as predictable in composites as in metals due to their variety. That makes it scary to an airline or airplane manufacturer.

This article is about bikes, but is a very good and not too technical explanation (google yields too much academia...):

If a material has a fatigue limit or “endurance limit,” it means that if the cyclic stresses applied to it are below a certain magnitude (measured in units like pounds per square inch), the structure will not fail due to fatigue. Look at the graph; if the stresses on the steel structure depicted in the graph are below about 28ksi (kilopounds per square inch) – or 28,000psi, the steel will never fail due to fatigue (of course assuming no rusting or impact damage). The fatigue curve for titanium looks similar. But you can see that the fatigue curve for aluminum never flattens out, so even small cyclic loads, if they go on long enough, will eventually cause it to fail.

Carbon fiber composites can indeed fatigue, but they do so very differently from metals. Metals tend to be isotropic (uniform in any direction), even though they can be mildly anisotropic in that they can have a predominant grain direction and, like wood, can be stronger along the grain than across it. (According to the coronial report you sent, this particular aluminum steering tube was not uniform in that it had an “inclusion flaw” in it.) By contrast, carbon fiber composites are extremely anisotropic, depending on how the layers of carbon fabric (usually unidirectional fibers) are laid across each other. And this can vary from fork to fork in the same batch, since the fabric pieces are laid up by hand.

Metals tend to eventually fail under fatigue at a single crack. Carbon fiber composites do not do this — they tend to degrade under fatigue throughout the entire volume of the structure. Composite materials fail due to fatigue in four basic ways: cracking of the matrix (i.e., the resin that holds the fibers together), delamination (peeling apart of one layer of fabric from another), breakage of fibers, and debonding of individual fibers from the resin. You may be able to hear delamination, debonding, and cracking by tapping a coin along the fork; where the matrix is intact, it will make a nice “clack” sound, whereas the sound will be deadened if layers have peeled away from each other or if fibers are cracked or no longer stuck together. Cracking of the fibers and/or of the matrix can be deep within the layers and may not be visible from the surface. Fatigue cracks in metal structures always propagate from the surface (the trick is finding the cracks when they are small).

https://www.velonews.com/gear/technical-faq-bottom-brackets-carbon-fiber-fatigue/

 

[256bits]

From the picture on the video still, it just looks as if the paint has suffered some premature ageing with flaking and stress cracking.
It could be the paint type and surface are not as compatible as they thought.
Environmental conditions such as variations in humidity or temperature can be the cause. The paint looks as if it has lifted off the surface in part. Perhaps the paint is drying out and not as flexible as when applied.

As well, of course, subsurface defects can be a cause, but the paint is there to protect.

Old paint on houses, cars, farm equipment dulls and ages and cracks from the environment.
Though the paint from the picture does not look as if it has oxidized and become chalky.

This is a picture of OLD paint on sheet metal.
Paint has dried up, shrunk, cracked and let moisture into rust the underlying surface.

 

[cjl]

The first flight of A350 was 2013. That's no longer new tech.

On a plane with an expected lifetime of 25-30 years (at least), 8 years is absolutely new tech. That's only just getting old enough to start to see how any aging related issues are playing out.

 

[DaveE]

Unless I hear more, I'm on Airbus's side here.

If they really have a structural issue, especially with this much attention, they want to know before it gets really bad. Boeing has recently taught everyone that pretending you don't have a safety problem isn't a good long-term strategy. Airbus also has the technical capability to do non-destructive testing or inspection of the laminate (Ultrasound, x-ray, thermography, etc.) or hire someone who does. There are lots of reasons the paint can fail without assuming it's a structural problem. They have more to lose than Emirates, et. al. It's easier for a dissatisfied customer to complain than for the manufacturer to prove (perhaps to the public) that the complaint is groundless or exaggerated.

OTOH, it's not great marketing to annoy your customers with ugly paint. Emirates may want to apply pressure to get cosmetic problems fixed, they may wish they hadn't signed a contract for a bunch of these planes and want a way out, or compensation for a quality problem. Repainting a plane, perhaps with a more expensive process or materials is expensive. Repainting more often than you expected is also really expensive ($100K-$200K plus time out of service). I'll take this at face value for now: the paint is ugly, but I'd fly on one of these (for now).

 

[propellerputzer]

Be aware
it was Qatar Airways not Emirates blaming Airbus.

Be aware too:

• CFRP on aircrafts structures is not new!
• Large part of fuselage at the A380 e.g. the tailcone but also VTP and HTP and other structure parts are made of CFRP.
• The Airbus A300-600 and all following Airbus models (A310,A320-family, A330 & A340 use since 1983 VTP and HTP made of CFRP - there is a long experience with "Surface Protection" by Primer, Paint and Decal Foils even with ageing effects.

Of course with A350 as well with B787 new CFRP-basematerials came into use - new fibers as well matrix (resin) had been introduced. Copper Mesh, Expanded Copper Foil for lightning protection were already used elsewhere in aircrafts. Long materials evaluations hab been done before certification of the materials including environmental degrading tests, including full scale fatigue tests under environmental degradation conditions.

Take also into account, that airlines periodically repaint their airvrafts (that is opposite to most cars, were you keep the paint until end of life), this is often done to improve the Brand of the airline and therefore to change the livre of their fleet.

In that cases you strip the old paint with chemical, some maintenance centers use deep temperature icing methods to peel off the paint, some use mechanical stripping - and maintenance centers sometimes approach that process in the oldfashioned traditional way they did it since years with metallic fuselage aircrafts - not fully reading the maintenance procedures and caution notes given by the aircraft manufacturers - that happnes more frequently than you think. (You can find lot of those cases of bad maintenance in the records of the authorities like FAA or EASA respcticvely the transport safety authorities like NTSB, TSB, BEA etc. following periodical audits, but it mostly does not become public)

There are other effects like aircraft cleaning (e.g. with Kaercher), de-icing, skydrol incidents if a hydraulic pipe connection etc. leaks or fails (Skydrol is a hydraulic fluid used in aircrafts, which is aggressive as it contains some acid components). Those things degarde paint but do not harm the CFRP struture itself - that has been intensively tested with the material certification.

That is the reason that Boeing, Airbus, FAA and EASA have stated, that the paint issue is a cosmetic but not a safety problem. Remeber, the paint problem has also hit Boeing B787 e.g. refer to Air New Zealand recent cases you can watch on YouTube too.

 

[dusty Dan]

The first paint problem was reported in 2016.
It is said the paint problem on the wings of the 787 is not related.

Whatever the problem is with the A350 paint Airbus has made it far worse by not fixing it and including the public. That leads to speculation which I will not do here.

 

[DaveE]

Airbus has made it far worse by not fixing it and including the public

Yes. And getting into a big public fight with a major customer. Painting airplanes is really expensive. OTOH, good PR, goodwill, and marketing are things companies also pay a lot for. Once you've screwed up in product development, it's often a case of pay now to fix it, or pay later, for a long time, in customer/market perception. It's one of the best things that's happened for Boeing recently.

 

[SNO]

Didn’t Airbus offer to fix all of Qatar’s A350 under warranty at no cost and Qatar categorically rejected, turning the issue into a drama?

 

[anorlunda]

Didn’t Airbus offer to fix all of Qatar’s A350 under warranty at no cost and Qatar categorically rejected, turning the issue into a drama?

That's covered in the video linked in post #1.

 

[SNO]

My post was addressed to DaveE and Dusty Dan.
I’m aware of the SimpleFlying youtube posting, it’s rather general, and it doesn’t mention, that AAB agreed to repair its planes after the Airbus CEO visited him personally only to recall his decision a few weeks later. Therefore I assume somebody above AAB is running the show, and AAB has to do as told to him.

Since this is a physics forum I’ve been hoping to find more info about the lightning mesh, how it is applied to the skin of the A350 fuselage, and more info about the adhesion/interaction of it with the layer above (I guess it’s the primer).

In the video released by Qatar showing the surface degradation there’s a picture showing the exposed metal mesh. The upper left corner of the mesh is soaked with raisin, the lower left corner is the mesh only, there is no raisin in the openings of the mesh. This raises the question: Is the mesh embedded into the carbon fiber parts or will it applied as the first layer on top of the carbon fiber parts, just before the primer layer is applied?
The surface characteristics are rather different between a raisin surface with the mesh embedded and the metal surface of the mesh glued onto the cfk parts. It could explain, why the primer is separating from the layer below at some places, but holds in other places due to differences in adhesion.

The issue with the primer losing adhesion on the metal surface of screws and rivets points into the same direction as the above symptom. The primer isn’t sticking well on metal surfaces.

There are also rumors in the web, that Airbus switched to a less dense lightning protection mesh, what might increase the non-metal surface for the primer to bond with. Still, the issue with primer not sticking well on metal surfaces remains.

More info about the adhesion between the primer and metal surfaces compared to other surfaces would be interesting. Another topic would be the chronologic history how Airbus selected the primer and color used today. Are they still using the same products today as they have used back then for the Qatari planes? The same can be told about the products used for the lightning protection.

 

[russ_watters]

Getting nastier:
https://www.businessinsider.com/airbus-canceled-remaining-19-a350s-that-qatar-had-on-order-2022-9

 

[DaveE]

Can't you just hear the champagne corks popping at Boeing?

"Several other carriers, like Etihad Airways and Delta Air Lines, have also noted degrading paint on their A350s, per Reuters, but none have made the same claims as Qatar nor say the damage is a safety threat."

"The European Aviation Safety Agency has backed Airbus by saying the paint does not impact airworthiness..."

 

[propellerputzer]

I think there is no reason for Boeing to open any bottle of champagne. They have so massive problems to certify their jets. 737 MAX 10 as well MAX 7 need to be certified until end of 2022, otherwise they have to redevelop their cockpit to meet safety standards in place already since over 30 years (the 737Max still works on safety standards from the 1960ties, which the worldwide autorities denied to use for aircrafts to be certified after 1.1.2023.

With the B787 they have so much trouble that they just recently restarted delivery after more than one year of trouble with the FAA because of massive quality problems in South Carolina after shutting the final assembly line in Everett. Don't forgett all the trouble Boeing had on the 787 with batteries, burned fuselage, etc. (iti's more a nightmare-liner than a dreamliner).
Next troublemaker is Boeing 777-X, which is delayed and delayed and delayed... lot of airlines try to replace their 777 orders with A350XWB, which are now available as Airbus deleted the orders of Quatar.

Not to forgett the troubel Boeing has with B767 tanker, the KC767. massive problems, delays and technologically far behind the Airbus MRTT, which sells worldwide rather good.
Finally the SLS Rocket and the CST-100 Starliner space programs don't look rather reliable... seems that the Boeing management is also acting not very well in the space programs. Shareholder value was more important than excellent engineering, which was skipped after the merger with Mc Donnel Douglas.

Whereas Airbus is still flying high in sales especially with the A320 family limited only by the shortage of jet engines from CFM and P&W. And it seems that Airbus is now happy to have stopped the sales with Qatar Airways and Akbar Al Baker. Akbar Al Baker is somehow the enfant terrible for the commercial departments of Airbus as well as Boeing - especially in case of deliveries. No Airline is such a nasty customer to look for even the tiniest irregularities - cosmetic imperfections to deny the take over and to request massive compenations.

So as the market for Airliners has changed because limited availability of delivery slots for airbus A320 family aircrafts and Boeing not able to deliver the B737 Max for years, and now the engine shortage, which hits Airbus as well as Boeing, it was easy for Airbus to get rid of a difficult customer, who was only very limited options to react - as said in this case Boeing has also not much to offer in short terms. And Airbus must not make any deal - discouts are only for nice customers, not for troublemakes. Qatar in the recent past was often so called launching customer - who gets really large discount for ordering a big fleet at once - taking over the risk of delays and dealing with (technnical) teething problems.

To get closer to the LSP with Expanded copper foil you may look into following Papers:
https://www.researchgate.net/publication/297050650_Lightning_strike_protection_for_composite_structures,
https://www.researchgate.net/publication/309231103_Lightning_Protection_of_Carbon_Fibre_Reinforced_Plastics_-_An_Overview_-
https://www.theses.fr/2020ESAE0027.pdf (this is a PhD-Thesis of an Airbus engineer, a very good source for insights)

By the way: the LSP-material used by Boeing as well by Airbus is called "Surface Master" see https://www.solvay.com/en/article/surfacing-smooth-flying. and https://www.solvay.com/en/product/surfacemaster905 - Checkaut the product data sheet

 

[anorlunda]

The topic here is not paint, not Boeing Versus Airbus.

The topic is the nasty fight between an airline and a manufacturer. It is very unusual.

 

[Motore]

The topic is the nasty fight between an airline and a manufacturer. It is very unusual.

Is it? I mean every agency except Qatari aviation authorities, stated that it is a cosmetic issue. And then Qatar Airways sued Airbus because they had to ground planes based on this issue (which only Qatar claimed it was an airworthiness issue). But don't forget that every major airline agency in the world grounded planes because it was mid pandemic. When Airbus hinted at that, Qatar Airways released a video showing the paint damage basically defaming Airbus. Of course Airbus should respond and they did. It perhaps escalated too much, but the company has a right to defend themselves as much as anyone.
The customer is not always right, they're seldom right.

 

[russ_watters]

Is it? I mean every agency except Qatari aviation authorities, stated that it is a cosmetic issue. And then Qatar Airways sued Airbus because they had to ground planes based on this issue (which only Qatar claimed it was an airworthiness issue). But don't forget that every major airline agency in the world grounded planes because it was mid pandemic. When Airbus hinted at that, Qatar Airways released a video showing the paint damage basically defaming Airbus. Of course Airbus should respond and they did. It perhaps escalated too much, but the company has a right to defend themselves as much as anyone.
The customer is not always right, they're seldom right.

So you favor Airbus here; what do you think Qatar's game is?

 

[Motore]

So you favor Airbus here; what do you think Qatar's game is?

I don't particulary favor anybody. I'm just trusting a statement that most agencies made instead of trusting the one that one agency made. In case of Qatar's game I don't want to speculate, but I guess for that price they should've got cosmetically almost perfect planes, which they didn't. But it's not an airworthiness issue as they claim, just cosmetic. So it seems like Qatar want's money out of Airbus (instead of just repainting) and the only way they can get it, is to show an airworthiness problem.
In the end I did speculate.

 

[anorlunda]

The unusual part is a manufacturer suing their own customers. It doesn't matter what the product is, or the complaint is. The number of airlines around the world is finite and small. It is not good business to alienate any of them because you hope they will be placing new orders in the near future.

 

[Motore]

It is not good business to alienate any of them

Perhaps not, but just letting wrong statements pass by will damage an aerospace company even more. As of now I don't know if any company beside Qatar's has declined orders of Airbus planes.

The unusual part is a manufacturer suing their own customers. It doesn't matter what the product is, or the complaint is.

It's not common, but if the lawsuit is legitimate I don't see a problem. Again: the customer is not and should not be perceived as being always right. I would think the company is aware of all the consequences of such a lawsuit and in this case they are taking the risk. We'll see if the brand will take a hit or not.

 

[etudiant]

It does seem as if the parties have a fundamental disagreement about the difference between 'cosmetic' and 'material'.
Qatar may have an extreme use case, most trips bounce from 40*C on the ground to -50*C in the air, so the surfaces get stressed especially aggressively. I believe they consequently wanted some regular refurbishment included for free, which Airbus was not willing to provide.
Not sure where this winds up, but I would expect the Chinese to be offering very attractively priced options, even though the Chinese industry is not yet really there.