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Cracks found in A380 wing ribs

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Cracks found in A380 wing ribs

Old 5th Jan 2012, 14:24
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Cracks found in A380 wing ribs

hello all just found this artical in the sydney morning herald Cracks found in A380s during Qantas repairs
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Old 5th Jan 2012, 19:38
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Design margins are too thin these days as engineers try to save weight.

This is why DC6s are still in revenue service today. The margins were greater then, admittedly, as they used sliderules and not CAD programs.

Just a sign of the times, but I'm willing to bet there won't be ONE A380 still in revenue service 60 years after the last one rolls off the assembly line.
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Old 5th Jan 2012, 19:54
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I don't think they will want a 380 to ferry sheep around in sixty years' time.
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Old 5th Jan 2012, 20:28
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DC3s, 6s, and other aircraft are sometimes called "flying barn doors" - pretty hard to break a barn door!
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Old 5th Jan 2012, 20:32
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DC-3/C-47

When I was flying air tours in the Otis Spunkmeyer DC-3s (C-41), I used to tell the passengers that the plane was designed before we had computers which told us how many times we could bend a piece of aluminum before it would break.

With the DC-1, Douglas built a wing and then drove a steam roller over it. The wing didn't bend or wrinkle, so the engineers figured that it was strong enough.

Last edited by Robert Campbell; 5th Jan 2012 at 20:33. Reason: spelling
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Old 5th Jan 2012, 21:00
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I thought the difference between good engineers and bad engineers is the ability to design to minimize cost and waste? Anybody can over design. What is the life cycle design parameters of an A380? Is it supposed to last 60 years?
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Old 5th Jan 2012, 21:16
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I think it's supposed to last longer than 3 years
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Old 5th Jan 2012, 21:22
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Sometimes it does pay to read an article before passing judgement:

The cause of the cracks in the Nancy Bird-Walton's wing is still to be determined but an initial assessment is believed to pin the blame more on the way the wing ribs were constructed rather than due to the loads and thrust at which the aircraft was operated by Qantas.
Manufacturing error is of course no small matter, but it's quite a lot less hassle to rectify than a design flaw.
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Old 5th Jan 2012, 21:41
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I clearly remember the A380 failing the wing loading test, it was news then the big delay became as a result of passenger service wiring!?! Fact is the wing barely made the grade (if there were not errors in the testing equipment) Expect more problems on this young aircraft!
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Old 5th Jan 2012, 22:52
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There are essentially three types of cracks: Fatigue, stress-corrosion and acoustic fatigue. Each has a different mode of behaviour. Fatigue cracks typically grow perpendicular to major loads, while stress corrosion often grows parallel to the major loads, and acoustic fatigue grows in thin material often in a non-linear fashion (as buckling modes change). Fatigue is directly related to loads, so that is a design and certification testing issue. Stress-corrosion occurs at grain boundaries in rolled, forged or extruded alloys and is usually a heat-treatment or materials selection issue. Acoustic fatigue is related to buffeting and may be difficult to design and test.

Do we know what alloy was used and the directions the cracks are growing?
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Old 5th Jan 2012, 23:11
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Storm, meet teacup

A380 Wing Cracks Not Affecting Operations | AVIATION WEEK
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Old 5th Jan 2012, 23:20
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there won't be ONE A380 still in revenue service 60 years after the last one rolls off the assembly line.
In sixty years...I expect this civilization to be living in caves and tending fires. In 2000 years, there will be another bunch of humanoids scratching their heads trying to figure out why the whole world is covered with concrete at least 45m wide and 3+ km long...
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Old 5th Jan 2012, 23:21
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There is waaaaaaaay to much conjecture regarding this issue at this early stage. For a start, I don't trust most media outlets to report technical issues such as this completely or accurately. Do they have access to the inspection/defect reports raised by the technicians at the airlines affected or are they in possession of a service bulletin from the manufacturer or an airworthiness directive from an airworthiness authority ? Even the spokesman for the industrial organisation covering Australian licensed aircraft maintenance engineers (which the local media calls 'engineers', confusing them with professional engineers) is stirring the pot on this issue this morning berating the local national airworthiness authority for accepting the EASA position on the approach proposed by Airbus in dealing with this issue.

I find it interesting that the SMH article appears in the 'Travel Incidents' section of the 'Travel' pages. What on earth is a travel writer going to understand about airworthiness issues?

This has been all over the news on radio this morning downunder. Here's a more 'informed' article from the ABC, reporting feedback from various parties:

Qantas A380 among planes with wing cracks - ABC Melbourne - Australian Broadcasting Corporation

There's a little more useful information in this article.
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Old 6th Jan 2012, 00:04
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Manufacturing error is of course no small matter, but it's quite a lot less hassle to rectify than a design flaw.
It is only a manufacturing flaw if they were not built as designed and that was the cause of the problem, otherwise it is a design flaw. The real question is the cost of the repair now they say it does not limit the aircraft (time + weight + material cost).

Last edited by Phalanger; 6th Jan 2012 at 00:28.
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Old 6th Jan 2012, 02:10
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Let's take a deep breath and read the description again carefully. Cracks have appeared in, "non-critical wing rib-skin attachments".

It is not cracks appearing in wing root box structures, a la F-111's. It is not cracks appearing in wing ribs. It is cracks appearing in wing-rib skin attachments.

When a wing flexes, as it does continously, it is inevitable that some minor cracking will appear in non-critical components attached to the wing structural components.
This is what is happening in this case. Nothing to see here, folks... move along.

Be more concerned about the composite components of the A380 that perform differently to metals... and which could be subject to decomposition and degradation over a relatively shorter period of time... as compared to the known and utilised metals in aircraft, that are inherently more stable, chemically and physically, over a far longer time frame.
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Old 6th Jan 2012, 08:38
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A380 Cracks

From the Melbourne Age:

A380 cracks: check fleets now, say engineers
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Old 6th Jan 2012, 08:55
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Anyone who has flown on a 380 and watched the wing bend and flex would have worries about how long this large piece of Aluminium that seems to have a strange bending moment about two thirds along it's length will last. Unlike other aircraft like the 747 which seems to have a uniform flexing of the wing along it's whole length the 380 has a totally different way of flexing so much so that I try to do my long haul flights to London on anything else except a 380. I hope that I am wrong but it looks like problems are just starting to appear.
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Old 6th Jan 2012, 09:49
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Wing flex

Anyone who has flown on a 380 and watched the wing bend and flex would have worries about how long this large piece of Aluminium that seems to have a strange bending moment about two thirds along it's length will last. Unlike other aircraft like the 747 which seems to have a uniform flexing of the wing along it's whole length the 380 has a totally different way of flexing so much so that I try to do my long haul flights to London on anything else except a 380. I hope that I am wrong but it looks like problems are just starting to appear.
Have you seen the wings of the B787 in action? I guess you will not be flying that one either?

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Old 6th Jan 2012, 11:31
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Ask any senior citizen

Flexible is good
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Old 6th Jan 2012, 13:31
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BH - If you have non-structural panels attached to structural sections, and those non-structural panels are on the outer areas of the structural members, where the most lineal movement is encountered during wing flex; it's not unreasonable to expect those non-structural members to develop minor cracks, that are of no concern.
These cracks rarely propagate into safety-threatening levels, and the attitude of Airbus towards these cracks recently found, seems to be quite reasonable.
Let me know the aircraft that you examine or fly, that does not have one minor non-structural crack in it somewhere, after several thousands hours of operation.
The A380's are in commercial service, and racking up the hours. The facts remain, that the only problems encountered so far, have been the engines (supplied by an independent supplier)... and this minor, non-structural cracking.
In an aircraft that is a totally new design, and of such size and complexity, I would say that the performance of the A380 to this point in time, is outstanding.
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