Cracks found in A380 wing ribs
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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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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.
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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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.
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 19:33. Reason: spelling
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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?
Sometimes it does pay to read an article before passing judgement:
Manufacturing error is of course no small matter, but it's quite a lot less hassle to rectify than a design flaw.
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.
Read more: Cracks found in A380s during Qantas repairs
Read more: Cracks found in A380s during Qantas repairs
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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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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?
Do we know what alloy was used and the directions the cracks are growing?
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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.
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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.
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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Manufacturing error is of course no small matter, but it's quite a lot less hassle to rectify than a design flaw.
Last edited by Phalanger; 5th Jan 2012 at 23:28.
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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.
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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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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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.
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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.