Cracks found in A380 wing ribs
 

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

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.

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

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

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.

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?

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

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!

So is this a manufacturing flaw?

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?

Storm, meet teacup

A380 Wing Cracks Not Affecting Operations | AVIATION WEEK

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

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.

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).

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.

A380 Cracks
 

From the Melbourne Age:

A380 cracks: check fleets now, say engineers

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:

Please explain further.

Wing flex
 

Have you seen the wings of the B787 in action? I guess you will not be flying that one either?