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-   -   Cracks found in A380 wing ribs (https://www.pprune.org/tech-log/473402-cracks-found-a380-wing-ribs.html)

rampman 5th Jan 2012 14:24

Cracks found in A380 wing ribs
 
hello all just found this artical in the sydney morning herald Cracks found in A380s during Qantas repairs

zerozero 5th Jan 2012 19:38

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.

fantom 5th Jan 2012 19:54

I don't think they will want a 380 to ferry sheep around in sixty years' time.

rotornut 5th Jan 2012 20:28

DC3s, 6s, and other aircraft are sometimes called "flying barn doors" - pretty hard to break a barn door!

Robert Campbell 5th Jan 2012 20:32

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.

mtwittm 5th Jan 2012 21:00

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?

Robert Campbell 5th Jan 2012 21:16

I think it's supposed to last longer than 3 years

SMT Member 5th Jan 2012 21:22

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.

grounded27 5th Jan 2012 21:41

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!

blakmax 5th Jan 2012 22:52

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?

SMT Member 5th Jan 2012 23:11

Storm, meet teacup

A380 Wing Cracks Not Affecting Operations | AVIATION WEEK

click 5th Jan 2012 23:20


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...:E

A30_737_AEWC 5th Jan 2012 23:21

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.

Phalanger 6th Jan 2012 00:04


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).

onetrack 6th Jan 2012 02:10

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.

pgrwrx 6th Jan 2012 08:38

A380 Cracks
 
From the Melbourne Age:

A380 cracks: check fleets now, say engineers

StallBoy 6th Jan 2012 08:55

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.:eek:

KiloMikePapa 6th Jan 2012 09:49

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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