Aer Lingus A-330 aileron castings
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Flaps perhaps, but ailerons? All explained by the SB.
Yes, VAPilot, and however they were made, their usefulness as attach points for the aileron actuators was seriously compromised. They are said to have supported an actuator at the outer end of the inner aileron on the right wing.
NDT on the fittings from the other wing is said to have found cracks in those two, as well.
So: is this a one-off, or is their a problem fleet wide? And if it's fleet wide, does that fleet include the A-340s?
NDT on the fittings from the other wing is said to have found cracks in those two, as well.
So: is this a one-off, or is their a problem fleet wide? And if it's fleet wide, does that fleet include the A-340s?
Before hearing about the SB regarding the manufacturing flaws or design deficiency errors, I was about to say how surprising it was to find flight control attach points failing completely due to turbulence.
Agree, but if fatigue, one would think it failed at less than designed for load?
bear
bear
Fatigue starts accumulating damage at stresses far below the yield strength and if rapidly cycled load are applied (vibatory) there is a Goodman" diagram of fatigue life vs static stress coupled with vibratory stresses
Major aircraft structures often are designed with a 150-200% margin against design limit static overloads, but still will fatigue operating at only 20% of that load.
In the quest to make light weight planes that can carry large fuel loads over long distances, even static load fatigue is an expectation requiring either life limits or inspections for the rest of their life to detect cracks before they seriously reduce the design margin of 150-200% mentioned above.
Add in an abnormal vibratory stress (buffeting, severe turbulence, rough landings etc.) and you may have to inspect more often based on specific in-service experience. All this is captured under "Continued Airworthiness" actions and reflected in constant updating of Service Bulletins etc.
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lomapaseo
My point is this: The failure cross section appears identical in each component, or there is a mirror behind one of them. The failure appears to have crossed the relieved area, indicating too much attention to weight relief, and the machined relic at the shoulder of the failure appears to be sharp, even uneased, concentrating a weak point at an already marginal support. Virtual testing should have identified this area, and even in a thirteen year old commercial a/c, this is a critical assembly to fail so unremarkably, even predictably.
Or this is an elaborate put up.
bear
My point is this: The failure cross section appears identical in each component, or there is a mirror behind one of them. The failure appears to have crossed the relieved area, indicating too much attention to weight relief, and the machined relic at the shoulder of the failure appears to be sharp, even uneased, concentrating a weak point at an already marginal support. Virtual testing should have identified this area, and even in a thirteen year old commercial a/c, this is a critical assembly to fail so unremarkably, even predictably.
Or this is an elaborate put up.
bear
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Both parts are machined forgings (not castings).
In the first picture:
The part on the left (in the mans right hand) failed due to fatigue. The beach marks on the fracture face are clearly visible in the photo.
The part on the right (in his left hand) shows evidence of fast fracture. Which would suggest it was over loaded when it had to take the load of the fatigued fitting. However, because there is not a real clear picture of the facture face, fatigue can not be ruled out.
In the first picture:
The part on the left (in the mans right hand) failed due to fatigue. The beach marks on the fracture face are clearly visible in the photo.
The part on the right (in his left hand) shows evidence of fast fracture. Which would suggest it was over loaded when it had to take the load of the fatigued fitting. However, because there is not a real clear picture of the facture face, fatigue can not be ruled out.
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Looks like a 'fails safe' structure that has failed!!!
The Back to Back structure is a typical 'fail safe' design.....only one is meant to fail before discovery of the defect.
I would look back in the archives if I were EI....there was an issue with Aileron PCUs around 1995-1997 where the servo control valves were incorrectly machined, causing excessive loads on the PCU body, the ends used to come off if they failed. This may have caused the start of the fatigue failure? Who knows? Lots of ADs around that time on them....(used to assist with trying to control the replacements, when AI could produce spares)... And yes same problem on A340......
The Back to Back structure is a typical 'fail safe' design.....only one is meant to fail before discovery of the defect.
I would look back in the archives if I were EI....there was an issue with Aileron PCUs around 1995-1997 where the servo control valves were incorrectly machined, causing excessive loads on the PCU body, the ends used to come off if they failed. This may have caused the start of the fatigue failure? Who knows? Lots of ADs around that time on them....(used to assist with trying to control the replacements, when AI could produce spares)... And yes same problem on A340......
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The Back to Back structure is a typical 'fail safe' design
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Maybe this following problem is starting to come home to roost?...
Degrees at RMIT 'dumbed down' for foreign students | News.com.au
Perhaps one of those "Middle Eastern students" who flunked aerospace exams... who was then was passed with "assistance", from Uni lecturers... has finally made his way into the design process??...
For an aeroplane component to fail from fatigue, seems to indicate, that at least some calculations were faulty.
It is possible, however, that manufacturing problems in the forging or machining, did lead to the failure.
We rely on good, skilled people to do the necessary engineering detective work, as to just exactly how the failure happened, and what needs to be done, to ensure it doesn't happen again, within regular use limits.
Degrees at RMIT 'dumbed down' for foreign students | News.com.au
Perhaps one of those "Middle Eastern students" who flunked aerospace exams... who was then was passed with "assistance", from Uni lecturers... has finally made his way into the design process??...
Investigators from the Ombudsman's office are believed to have discovered the cheating during an investigation into other damaging claims against RMIT.
They found evidence suggesting a long-serving teacher handed out an exam paper to a Middle Eastern aerospace student several days before the exam.
The student allegedly allowed other Middle Eastern students to use the exam paper to cheat.
Telephone records of the teacher and several aerospace students allegedly reveal late-night contact in the days before a test on the stress on aeroplane components.
They found evidence suggesting a long-serving teacher handed out an exam paper to a Middle Eastern aerospace student several days before the exam.
The student allegedly allowed other Middle Eastern students to use the exam paper to cheat.
Telephone records of the teacher and several aerospace students allegedly reveal late-night contact in the days before a test on the stress on aeroplane components.
It is possible, however, that manufacturing problems in the forging or machining, did lead to the failure.
We rely on good, skilled people to do the necessary engineering detective work, as to just exactly how the failure happened, and what needs to be done, to ensure it doesn't happen again, within regular use limits.
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For an aeroplane component to fail from fatigue, seems to indicate, that at least some calculations were faulty.
It is possible, however, that manufacturing problems in the forging or machining, did lead to the failure.
We rely on good, skilled people to do the necessary engineering detective work, as to just exactly how the failure happened, and what needs to be done, to ensure it doesn't happen again, within regular use limits.
It is possible, however, that manufacturing problems in the forging or machining, did lead to the failure.
We rely on good, skilled people to do the necessary engineering detective work, as to just exactly how the failure happened, and what needs to be done, to ensure it doesn't happen again, within regular use limits.
'Detective work' should start with an open mind, not vague suggestions that engineers have cheated in their exams.
I've still seen sod-all in this thread about the immediate circumstances of his failure, or indeed about it's potential consequences. All we seem to know is that something big and photogenic broke - twice...
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For an aeroplane component to fail from fatigue, seems to indicate, that at least some calculations were faulty.
I am sure the parts were give an complete examination including metallurigic analysis and the source of the failure has been identified.
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glhcarl
Suggesting a unique failure pattern for one of these hinges demands a similar artifact in the other. If inadvertent, it was repeated in its partner, quite unlikely.
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
The outstanding question, where is the aileron? In the Lake? We know they float.
Suggesting a unique failure pattern for one of these hinges demands a similar artifact in the other. If inadvertent, it was repeated in its partner, quite unlikely.
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
The outstanding question, where is the aileron? In the Lake? We know they float.
Suggesting a unique failure pattern for one of these hinges demands a similar artifact in the other. If inadvertent, it was repeated in its partner, quite unlikely.
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
The outstanding question, where is the aileron? In the Lake? We know they float.
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
The outstanding question, where is the aileron? In the Lake? We know they float.
There seems to be enough of both hinge points left for an easy confirmation in a lab. Some engineer and metalurgist has no doubt seen similar in these parts and already is working out corrective action as we write these words.
We could be having this disussion in the technical session
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Suggesting a unique failure pattern for one of these hinges demands a similar artifact in the other. If inadvertent, it was repeated in its partner, quite unlikely.
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
By the same token, similar breaks in mirrored parts suggests rather strongly a shared defect, and most likely in design. A separate though similar component failing in virtually the same way, right?
The outstanding question, where is the aileron? In the Lake? We know they float.
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For an aeroplane component to fail from fatigue, seems to indicate, that at least some calculations were faulty.