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

lomapaseo 6th Jan 2012 10:31

Ask any senior citizen

Flexible is good

onetrack 6th Jan 2012 12:31

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.

A33Zab 6th Jan 2012 15:26

@StallBoy:
 

I try to do my long haul flights to London on anything else except a 380
keep being ignorant.
Boeing's don't crack, corrode or have other system/engine failures.:rolleyes:

Another nice wingflex video:


grounded27 6th Jan 2012 15:34

At least the 787 passed the load test the first time.

Bend Not Break: Boeing 787 Passes Wing Load Test - CBS News

Unlike the a380 like I had mentioned above and referenced here.

Airbus A380 test wing breaks just below ultimate load target


What was interesting is Boeing traditionally pushes the first one until it pops, mentioned in the first article b777/1994 at 154%. Sounds like they got what they wanted out of the 787 and called it a night. I would like to know what the B787 wing is actually capable of.

blackhand 6th Jan 2012 19:46


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.
Onetrack, I was asking as you posted with a confident engineering outlook.
I have some basic engineering theory, but more a journeyman than a theorist.
After several thousand hours of operation I would expect to find minor cracking, even in structural components. The Airbus 380 in question did not have thousands of hours of operation.
One has carried out inspections on aircraft over the last several years and have not noticed cracking in the rib to skin attach on any.
Airbus do not consider it an immediate airworthiness isse which should allay safety concerns.
Cheers

lomapaseo 6th Jan 2012 20:46


At least the 787 passed the load test the first time.
The more tests the more you know and understand (these things have oodles of information collected)

With one succesful test you only know that it's good enough. With multiple tests you know by how much.

Of course the development time and money matter a little bit to the bottom line.

18-Wheeler 6th Jan 2012 22:08


I would like to know what the B787 wing is actually capable of.
A quick sidetrack here - I have always been impressed by that China Airlines 747-SP that did the aerobatics over the Pacific. They pulled around 5G's twice and the wings were bent, but did not break.

riff_raff 6th Jan 2012 23:17


The more tests the more you know and understand (these things have oodles of information collected)...With one succesful test you only know that it's good enough. With multiple tests you know by how much.
lomapaseo,

In the aircraft industry, structural qualification tests are not really performed to collect data or to investigate how a particular component will respond to loads. Instead, the primary purpose of structural qualification testing is to validate the analysis used to design the component. As you noted, there is lots of data acquired during a structural test, and this data is used to improve the analytical models. A complex structure like an aircraft wing might be analyzed for 50 or more different load cases, but it is not tested for each of those load cases. I don't mean to discount the value of testing, but when an aircraft design is certified it is the analysis results that really count. The testing is really just a check to ensure that the analysis work was accurate.

As for structural cracks, there should not be any if the aircraft is maintained and operated within design parameters. However, aircraft structural designers acknowledge that cracks may occur for any number of reasons, and they perform detailed analyses just for these conditions. All critical aircraft structures have a Fracture Control Plan, which outlines how the structure will respond to cracks, how cracks will be prevented, and how cracks can be detected when they occur. Aircraft companies employ analysts specializing in fracture mechanics, as well as numerous QA and manufacturing process engineers to develop fracture control plans.

DTDHandbook | Guidelines for Damage Tolerance Design and Fracture Control Planning | Guidelines for Damage Tolerance Design and Fracture Control Planning

halwise 7th Jan 2012 17:44

Airbus A380 should be grounded....
 
Not seen this anywhere before....
BBC News - Airbus A380 fleet should be grounded, say engineers

Dengue_Dude 7th Jan 2012 18:45

Aircraft crack . . . it happens.

Provided it's being monitored. It can't be that serious if there's a 4 yearly inspection/repair scheme.

RodH 7th Jan 2012 18:50

It would seem that the Engineers who made these suggestions are working for the wrong people. They obviously know far more the the manufacturers so they should be some of their top people.
A simple phone call to Airbus would surely have them so excited about getting such experts to sort out any problems they may have.
Or maybe it should be left to those who designed and bulit the aeroplane.
They may be a tad better at making such a decision.
Airbus aren't stupid , they would make sure it was attended to immediately if they thought it necessary.
Maybe watching the cricket might be better than making these suggestions.
:=:=:=

Skipness One Echo 7th Jan 2012 19:01

This will be the same QANTAS engineers that hate the fact that their work is being outsourced to Asia. Axe and grind springs to mind alas.

Jackneville 7th Jan 2012 19:08

TRUST ?
 
To those who proclaim, "trust the Manufacturer, they know best " and "trust the Regulator they're a Government Body", I'd say, yeah right.....United 747, Fwd Cargo door, PHNL, remember ?

Boeing and the NTSB didn't come out of that looking too flash.

oldchina 7th Jan 2012 20:05

"Cracks have been found on the wing ribs of at least three Airbus A380s belonging to Singapore Airlines and Qantas Airways.
Both carriers said the cracks were discovered in the 2nd quarter of 2011, and that they have been repaired and posed no danger to safety."

Sorry Jackneville, Qantas mechanic.

11Fan 7th Jan 2012 20:19

Sorry, I thought I was on A.net for a moment. :hmm:

Topspotter 7th Jan 2012 20:40

As i understand it if structural damage is reported or found during a inspection then the SRM which is supplied by the manufacturer is the document that is the authoritive guide to engineers in dealing with that defect ,The SRM will state if the damage is within limits/ out of limits can be repaired/ cannot be repaired/ how it is to repaired ect.

Engineers no doubt use the SRM day in day out and i presume trust it to ensure aircraft remain airworthy, so whats different about this case? why do they suddenly not accept what airbus are saying, ie the damage is acceptable and repair can be defered

V1... Ooops 7th Jan 2012 22:30


Originally Posted by Skipness One Echo (Post 6941774)
This will be the same QANTAS engineers that hate the fact that their work is being outsourced to Asia. Axe and grind springs to mind alas.

I think the above has a lot to do with all the media coverage of this matter. I recently saw a televised interview with an Australian based AME who was demanding that the aircraft be grounded - that kind of public posturing is quite uncommon in our industry.

Topspotter 7th Jan 2012 22:50

Speaking for myself i have always found licensed maintenance engineers to be very down to earth ,dedicated, knowlegable people and certainly not the sort to cry wolf, if their concerned id be inclined to listen.
No doubt the moves to outsource work away from Oz is one which is causing emotions to run high and hardly suprising, if my job was being outsourced to Asia id be a tad concerned, but quite what that got to do with the point in question im not sure

lomapaseo 7th Jan 2012 23:34


Speaking for myself i have always found licensed maintenance engineers to be very down to earth ,dedicated, knowlegable people and certainly not the sort to cry wolf, if their concerned id be inclined to listen.
spot on Topspotter, except where emotionalism over one's salary gets into it.

By the looks of this thread everybody's opinions are suspect by somebody.

Well since we can't just sit around expecting Gus at the corner bar to fix it, I guess we're going have to just let the system that we've got get on with it.

11Fan 8th Jan 2012 01:35

As long as Ted doesn't screw up, no worries.

http://img98.imageshack.us/img98/5318/wingsye5.jpg


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