A380 having a cracking time

[Firebex]

I noticed a report in the last few days that checks are having to be carried out on the wings of all 60 Airbus A380 super jumbo's in service.

The report suggested that a number of the aircraft on recent maintenance checks had been discovered to have some significant cracks in the inboard upper wing surfaces ?.

A statement was read out that stated it was a routine matter and not considered to be serious enough to cause any concern.

Pardon me but I would consider checks on a major airliner due to cracks being found in the wings something that could potentially be serious or a cause of concern. Not very routine ??

Anyone heard anything more as its gone a bit quiet since the report on the lunchtime news yesterday I think it was,no info on the aircraft or airlines concerned.


Mike E

[Arthur Pewtey]

If the cracks are small or in non-critcal areas then they may not be of great concern. Service Bulletins for checks to be carried out or modifications to be done are issued regularly on all aircraft without there being any cause for alarm. I don't see this as being any different.

Why is this in GD?

[John Green]

Firebex

You're absolutely correct to be concerned. The report that I heard on the radio mentioned some part connected or adjacent to the wing ribs. The tendency is for the manufacturer to play down these matters to avoid creating or exacerbating public alarm. We don't want people refusing to use the a/c do we ? Comet and DC10 memories persist.


John Green

[PeeDee]

Arthur.
It aint going to go away, a crack can only grow and get worse.
It probably isn't of concern because it is not part of the Wing Box. If it's part of the L/e or T/e overhangs or panels, well...it can fly even if these ping off into the breeze. So long as it doesn't hit the tail of course.

[Arthur Pewtey]

The aircraft that hasn't got a crack in it hasn't been built yet.
Crack propagation is well understood and can be contained within the design.

If you want to be alarmed by this, go ahead. The rest of us will realize that it is not likely to be a big deal.

The climate of fear is alive and well.

What cracks were there in the DC-10 that were so problematic?
The Comet was a fatigue issue before metal fatigue was even properly understood. The problem with being a pioneer.
Technology has moved on a long way from then.

Why is this still in GD?

[PeeDee]

I sit amongst A/c designers daily Arthur, they run dozens of FEM models and other load line s/w and check it afterwards with a Brain.
There is no accomadation of a crack, they predict where a crack could happen and design it out. So, any crack is a design failure....fear culture or not.
As I said, if it's just an aerodynamic panel, it's no worry. Whoever designed it and made it will have to do a retrofit with one that does what it says on the tin. If it was Wing box, they would have grounded the fleet. Again.

[bazv]

Biggest wing cracks I ever saw were on B52's,I suppose they must have all been grounded years ago...oh wait they are still flying !
I agree with Arthur...I have known intimately 8 different a/c types in my 40 years as a technician...they all had cracks - some fairly large and some in fairly crucial areas,at a distance one cannot say with certainty whether these cracks are significant or not but you can be sure that almost every airliner in the world has some significant cracking somewhere in its structure
Many crack prone areas on a/c are identified on the a/c fatigue stress rigs,these suspect areas are then checked using NDT tests.

rgds baz

[pistonrob]

at least nowerdays we are mostly in a position to discover faults like this before they lead to a possible major malfunction or disaster before they happen..

as usual the press have got hold of a mole hill and made it a mountain

[tornado64]

Arthur.
It aint going to go away, a crack can only grow and get worse.
It probably isn't of concern because it is not part of the Wing Box. If it's part of the L/e or T/e overhangs or panels, well...it can fly even if these ping off into the breeze. So long as it doesn't hit the tail of course.

not completeley true a crack can be stopped by drilling a hole at the end of it !! but that does not get rid of what is sounding to be a design / materials problem for them to be there so early in a brand new aircrafts wing

whilst technicly it sounds a good idea i have watched the movement in the machines wings at manchester for a brand new idea of building the wings it may prove a costly error not testing for many years before commiting to such a costly preduction run

[PeeDee]

Baz.
Nobody is arguing.

But this platform has only a few thousand hours under it's belt.
The MAFT rig should be well ahead of it of course, and the crack will have shown up in the Rig specimen, so Airbus will be watching it "Ahead" of the living fleet. We hope.

B-52's. Every one of those beauties had twisted Fuselage sydrome. You can see the buckling most glamorously on the one at Duxford. The light from the side catches it very well indeed.
They may not have been grounded, but they have been re-spared plus other structure replaced. Is it still on target to be the first 100 year Aeroplane? From first flight to last retirement..100 years. IIRC it has to get to 2049? Obviously, not the same one!

[tornado64]

like triggers broom !! would there actualy be any parts left that were actualy 100 yrs old ??

[John Green]

Re 5

Arthur Pewtey

You miss the point. It is the memory of aircraft failures, irrespective of the type of failure, that triggers the sweat glands. See you on board - I don't think !


John Green

[bazv]

I am not arguing either PD
I was merely suggesting distancing oneself from media reporting of any a/c structural problems,unless one has insider knowledge of this particular problem - it is impossible to have a meaningful discussion about it...but then again it is more fun to just do some Airbus bashing

BTW I am not a fan of the 380...it is an ugly thing...but most internet 'discussions' about airbus a/c are errrr...shall we say ''slightly innaccurate''

[Arthur Pewtey]

Re 5

Arthur Pewtey

You miss the point. It is the memory of aircraft failures, irrespective of the type of failure, that triggers the sweat glands. See you on board - I don't think !


John Green

I've been involved in civil aviation for 25 years in a professional capacity. 21 of those in flight test . I am aware what goes into designing, testing and certificating modern airliners. I am happy to fly in any Airbus (or any other type for that matter) If you choose not to fly that is your choice. It is your loss. It would appear that the press coverage of this issue has indeed had the desired effect and created the "climate of fear".

Still don't know what cracks were a problem in the DC-10 design.

[J Boyle]

Is it still on target to be the first 100 year Aeroplane? From first flight to last retirement..100 years. IIRC it has to get to 2049? Obviously, not the same one!

The B-52 first flew in 1952, not 1947.
I don't now if the fuselage wrinkels have anything to do with dangerous fatigue. If it was a Comet-type danger, the USAF would have fixed them long ago.
Also, I'm not sure if they've been re-sparred. I don't think so.

Even the B-47s weren't re-sparred when cracks were found after the high stress LABS maneuver. Wings were sunjected to Non-destructive tests and in any effected areas fasteners were removed, holes were reamed oversize and larger fasteners fitted. The same procedure was done with the "Milk bottle" wing-join pin. It wasn't that major of work, in 1958 alone, 895 aircraft were modifed. In total 1230 Stratojets were so modified. The work could not have been done that quickly if the fleet had be re-sparred.

They really don't have that many hours of them.
In 1991, (when they were 30 years old) the B-52Hs had an average of 12,300 hours, that's from a declassified AFLC B-52 Weapons System Program Assessment briefing I have in my files. That was after the Desert Storm combat surge....so if you add another 20 years to that figure, the Hs probably now have about 20,000 hours on them.

[J Boyle]

What cracks were there in the DC-10 that were so problematic?

What DC-10 cracks?
The DC-10 may have some issues, but fatigue cracks are not among them...to the best of my knowledge.

The Comet was a fatigue issue before metal fatigue was even properly understood. The problem with being a pioneer.
Technology has moved on a long way from then.

Not quite. Though metal fatigue was new to aircraft, what doomed the early Comets was fatigue brought on by pressure.
Those dangers were understood as far back as the 1860s...that's why boilers are round as are their inspection ports.
According to RAF pilot and aviation engineer turned author, Bill Gunston, the Comet losses were totally preventable.

In any event, minor wing cracks are to be expected. What's odd is that they're showing up this early in the A380s service life.
Overall, no big deal.

I'll wager that the 787 has similar issues...and the media will also blow it out of proportion.

[Arthur Pewtey]

What DC-10 cracks?

Indeed. A new one on me and one that will remain a mystery I suspect.

What I meant with the Comet was the mechanisms of fatigue were not properly understood. Other manufacturers learnt a great deal from the Comet. Now that there is better understanding of the issues, it is very easy to say that the accidents were preventable. With the benefit of hindsight, all accidents are.

[J Boyle]

Now that there is better understanding of the issues, it is very easy to say that the accidents were preventable. With the benefit of hindsight, all accidents are.

But the basic cause of the Comet disasters was well-known at the time...and thus preventable.
You simply don't cut a square hole in a pressure vessel.

[paul178]

Just suppose you had enough money to buy a Bugatti Veyron and it developed cracks in it all singing and dancing spoiler. On mentioning it to the supplier you were told "Its quiet safe no cars crashed due to it yet" Would you say "Ok then" and bimble off?

[Arthur Pewtey]

I didn't think it was fully understood.

The full implication of the design was obviously not understood by de Havilland's engineers. What a shame that neither those that knew or the authorities that certificated the design told them their design was unsafe.

[paul178]

Well Arthur are you trying to tell us that we fully understand everything about a new generation aircraft made of all sorts of composite materials and fixings and it is unlikely never to crash killing 500 souls and any who happen to be underneath it at the time? Or you might never happen to get part of a Rolls Royce Trent engine on your lap? Just because we can make something bigger does it mean we should?

[Mr Creosote]

I think the notion of the DC-10 having crack problems stemmed (unjustly) from the American Airlines crash in 1979, when an engine fell off shortly after take-off. American's maintenance procedures -mainly in using a forklift truck to change engines- was held largely responsible, but in the public's mind the DC-10 gained a reputation for cracks; hence the old black humour about the DC-10 "Not being all it's cracked-up to be" etc.

http://en.wikipedia.org/wiki/America...nes_Flight_191

[Arthur Pewtey]

We understand the processes enough to make aircraft the size of the A380 safe to fly. We also have in place a rigorous set of checks designed to catch potential problems before they affect the safe operation of the aircraft

Did we have these debates when the 747 appeared? Probably. It seems to have done all right though.
We can never make it 100% safe - nobody can. We can however make them as safe as possible.

Then again, maybe you're right. Maybe we should go back to using a horse and cart. But then again a wheel might fall off and kill somebody ................

[PeeDee]

B-52 Spars. I didn't mean (Or suggest) that they were re-Sparred because of any fails. I'm sure I read they were re-spared to ensure an extra life span, which would take the potential service life into the 2050's.
The Fuse obviously wasn't a problem, it must have been checked out properly because the visible evidence is so blatent.

As for the present cracking news. It's a Qantas jet too, they must be getting a bit concerned/peed off with the A380.

I also think it's one of the ugliest A/c ever made. But, I might be applying for a job back at Airbus so that's where my opinion stops!

Duxford B-52. They are all like this (Well, all the ones I've seen).

[Firebex]

I see I have stirred up a lively debate .Just to update I see that Quantas and one of the other operators has had to GROUND a couple of airframes for further inspection and investigation as some of the cracks are in areas that require further indepth investigation apparently.Make of that what you will ???

It is a shame they seem to be having so many hiccups with this aircraft but it seems multi national projects attract lots of issues.I can think of at least two major early issues on A380 relating to cable end fittings and plugs and dimensions of some components and undercarriage doors causing significant delays.

Dont get me wrong I think its is a very good aircraft but perhaps it needed a bit more work on it and perhaps politics outweighed production priorities.

Mike E

[Flatcat]

I've inspected a few airframes over the years, and in general, are cracks good?
Of course not, but are they always reason to ground a plane -no.

Remembering designing a plane (or most things for that matter) is complex and it's not all about making it so strong it won't break.

There's the bit about ensuring that if it does crack how to limit the propagation of it by design (think say, 3 piece spars, if a crack develops it can only travel to the edge of the material)

Then there's redundancy in load paths, so if a crack does develop then the load can transfer through other joints.

Then there is inspection frequencies, they are not chosen by a random number generator, but by careful calculation on expected failure rates, after all these cracks were not found after the wing fell off, but during a maintenance process.

The design teams hopefully have applied learnings from others failures, in particular to the aluminium components, but remember that FRP components have been in use for many years now too. It would be a brave man to say it won't happen, but it would be a foolish man to discount the engineering knowledge that has gone into any modern aircraft.

[John Green]

Re 17

Nowhere, in any previous comment did I write that the DC10 had experienced airframe cracking. My comment about the Comet and DC10 mentioned 'memories'. Memories of structural failure.

With the help of your twenty five years in the business, you must remember the problems with the DC10. Imprecise as my memories are, did it not involve the collapse of a section of the floor of an aft cargo bay in connection with an improperly closed aft cargo door? I remember one incident involving substantial loss of life of a returning party of rugby supporters somewhere over France.

I know that it is by empirical means that the human race proceeds thru' life. The problem is that when we get it wrong in the air, it is very final. I believe that commercial pressures have much to answer for.


John Green

[Arthur Pewtey]

I'm not sure how a thread about A380 wing component cracking invokes memories of DC-10 accidents? As you said, the DC-10 accidents were caused by cargo doors which could be appear to be correctly closed when they weren't. Nothing to do with fatigue at all. Subsequent modification ensured that that particular failure could not happen again. Sadly in this case it took a fatal accident to find a problem but in the A380 case an inspection has found the problem. It will be fixed and the aircraft will return to service.

All aircraft go through continual development and refinement throughout their lives which makes aircraft safer with each passing year.

[Ritch & Max]

Hi all

Untill a few weeks ago, I worked for the company, based in Nottinghamshire who manufacture the parts concerned.

The wing rib is a very large one piece vertical web, with lighteneing holes, vertical and horezontal stiffeners etc all machined into the rib, also machined in are the web feet, which are basicaly angled brackets (cleats) machined to fit between stiffeners (stringers) machined into the top and bottom wing skins. The feet are then attached with mechanical fasteners to the wing skins to form the wing assembly.

If the feet should for any reason shear, then the skins are no longer attached to the ribs, simple as that. And with a wing full of a large weight in fuel, it is a very serious situation.

There are answers to both improvments to new wings and ways to repair the existing ones. There have been big changes at the manufacturer concerned, including top managment changes. But that is about all I can say without risk of legal action.

[John Green]

Re 28

Let me enlighten you. It's about flaws in transport a/c design or manufacture.

John Green