Qantas A380 uncontained #2 engine failure
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I am not a Statistician. One in one million? One in Ten Million.?
Absolutely NOT. This incident happened due to a KNOWN defect MEL'ed to allow Public Carriage across inhospitable terrain. That is inexcusable.
MEL'ed by an authority via an accepted method of compromise, with considerations made for easing the struggle of profitmaking.
I say One in five thousand? One in One Thousand? one in ten? I think some time should be taken to think again about the "Odds".
bear
Absolutely NOT. This incident happened due to a KNOWN defect MEL'ed to allow Public Carriage across inhospitable terrain. That is inexcusable.
MEL'ed by an authority via an accepted method of compromise, with considerations made for easing the struggle of profitmaking.
I say One in five thousand? One in One Thousand? one in ten? I think some time should be taken to think again about the "Odds".
bear
We've been here before... Those figures are pretty meaningless until you state whether this is per flight or per hour, or per some other measure.
CJ
CJ
Flight safety statistics generally follow the thinking in regulation 25.1309 and are stated per hour. That's what I assumed BOAC was commenting about
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Whether or not the test cell explosion of the 1000 is related, or the "Oil where it shouldn't be" could have saved this mess from happening had a more conservative approach been applied, discussions of Flight Safety and its Statistics could not be more irrelevant, imo
ADs, workarounds, business decisions, dispatch considerations, etc. and the ever present bottom line? Throw in RR's "What did they know and when did they know it?"; to include why did they not divulge the "new Modification", and......Everyone knew about the problem, knew of its potentials and its costs. Decisions were made, sadly, due to ongoing endeavours that sublimated Safety, imo.
Does anyone think there were NO engineers at Derby who entertained this possibility (explosion)? Let's retreat back into reality.
bear
ADs, workarounds, business decisions, dispatch considerations, etc. and the ever present bottom line? Throw in RR's "What did they know and when did they know it?"; to include why did they not divulge the "new Modification", and......Everyone knew about the problem, knew of its potentials and its costs. Decisions were made, sadly, due to ongoing endeavours that sublimated Safety, imo.
Does anyone think there were NO engineers at Derby who entertained this possibility (explosion)? Let's retreat back into reality.
bear
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My venture into the world of 'statistics' was not intended to start a shouting match, more an innocent -"OK, we've used up the 1 in 10 zillion probability. What are the next odds with a possibly 'known' defect'?
Bear - your use of the term 'MEL'ed' puzzles me - I have not followed your 'knock-about' with the legalese side of contracts, but I thought the drift was that Qantas were 'unaware' of the problem? The term 'MEL' implies something placed on the operation by the operator - is that what you are saying?
I remain fascinated with the thought of how close we came to throwing 450+ people into the sea and again ask what effect the 'experts' here think this will have on certification. As a 'learned' aviation engineer friend asked - what do I think D P Davies would be saying right now?
Bear - your use of the term 'MEL'ed' puzzles me - I have not followed your 'knock-about' with the legalese side of contracts, but I thought the drift was that Qantas were 'unaware' of the problem? The term 'MEL' implies something placed on the operation by the operator - is that what you are saying?
I remain fascinated with the thought of how close we came to throwing 450+ people into the sea and again ask what effect the 'experts' here think this will have on certification. As a 'learned' aviation engineer friend asked - what do I think D P Davies would be saying right now?
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It is in the nature of the way I write. MEL'ed is exactly as you say. In this case, I use the acronym to emphasize that Qantas was taken "Out of the Loop". It was a Minimum constructed by the Authority, the AD served as an ad hoc MEL. With leased power, and RR in contact with the authority, Qantas was deaf and blind here. That is the part of my contracts rant I think is most important. For a virtually new powerplant to require such close scrutiny, and oversight, is unusual enough to have raised flags with Qantas, of course, they are not innocent here. It is this "blurring" of responsibilty in Aviation that has me upset, this "Plausible Deniability". To believe otherwise is to accept the Authority, The Manufacturer, and the Operator as blazing idiots. Not the case, so while there is much strutting and massaging of the Press, the really important question is hidden.
How the Hell did this happen; who needs to be prosecuted, fired, and fined to clear the decks of dangerous deadwood. This flight came within a hair of being lost at Sea. We discuss Money lost as if it is the fulcrum of the discussion. Shame on us all.
bear
How the Hell did this happen; who needs to be prosecuted, fired, and fined to clear the decks of dangerous deadwood. This flight came within a hair of being lost at Sea. We discuss Money lost as if it is the fulcrum of the discussion. Shame on us all.
bear
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Apology, yes, I did.
Thanks.
I always prefer to add the "per hour", to avoid confusion with other statistics, such as "per flight", or "per cycle" or (different statistics) "per million passenger miles", etc.
CJ
Flight safety statistics generally follow the thinking in regulation 25.1309 and are stated per hour. That's what I assumed BOAC was commenting about
I always prefer to add the "per hour", to avoid confusion with other statistics, such as "per flight", or "per cycle" or (different statistics) "per million passenger miles", etc.
CJ
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The continued insistence by some that this was a disaster narrowly avoided, and mostly by luck at that, and the 'what if's' -that seem mostly constructed for the purpose of proving the first claim- is becoming a tedious theoretical game. And is leading nowhere.
Everything can be a disaster narrowly avoided, if one chooses to make it so. It is merely a matter of making a 'what if' that suits the purpose.
Everything can be a disaster narrowly avoided, if one chooses to make it so. It is merely a matter of making a 'what if' that suits the purpose.
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Originally Posted by one outsider
The continued insistence by some that this was a disaster narrowly avoided
If one does not explore 'what-if's' in aviation then aviation will bite your bum.
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Don^t move the jettison ports, please!
barit1,
Why would you want to relocate me to the THS...???
> Where are the fuel dump ports located on the A380?
Check out the following picture - the "most outer one but one" (is that Queen^s english???) flap track fairing shows the AI typical rubber hose, sorry: "anti-corona device" for a jettison exit.
2.bp.
blog
spot.com
/_gFSicxXekVQ/Sw2dxRBZEpI/AAAAAAAAA_4/bGqbTeMPSP4/s1600/a380_wing_over_overcast.jpg
If anyone could shed a light why AI installs the "anti-corona device" while Boeing just puts a metallic tube at the end - I would be grateful! It^s the same fuel after all, and same ambient conditions, no?!
> Did they consider locating them on the horizontal stabilizer, considering that the tail fuel very possibly would be the first we need to dump?
Hmmm... The tail contains about 22t max, if I remember correctly. However, in a situation that requires dumping you probably would want to dump more than that.
Now, you could pump parts of the wing tanks fuel through the aft fuselage to the THS ports. But what about flow rates? And what about the case of an UERF that in fact punctured the fuselage and severed the trim line? Then, jettison would be impossible.
I think it^s much easier and more reliable to put the ports on the wing. This is where the majority of the fuel is, this is where you have the powerful pumps. The vicinity of the engines seems to be no problem, and while I have to say that I understand your CG concerns:
I hardly remember any CG issues on the A330/A340s, and they even have a complex CG control system, i. e. aft and fwd xfers are possible in flight. (The A380 on the other hand only has a "bucket in the tail", similar to those B744s with a tail tank.).
I know of one significant issue once with trapped fuel in the THS, on an old A340 which does not have a proper xfer pump (relies on head pressure for fwd xfer which may not be sufficient under certain conditions).
Apart from that: Good reliability of the CG control system, redundancy in valves and control. No worries there.
Conclusion:
I think keeping the ports where they are is much simpler and also more reliable.
Cheers,
J.V.
(not a designer, just a poor little 145er
)
Why would you want to relocate me to the THS...???
> Where are the fuel dump ports located on the A380?
Check out the following picture - the "most outer one but one" (is that Queen^s english???) flap track fairing shows the AI typical rubber hose, sorry: "anti-corona device" for a jettison exit.
2.bp.
blog
spot.com
/_gFSicxXekVQ/Sw2dxRBZEpI/AAAAAAAAA_4/bGqbTeMPSP4/s1600/a380_wing_over_overcast.jpg
If anyone could shed a light why AI installs the "anti-corona device" while Boeing just puts a metallic tube at the end - I would be grateful! It^s the same fuel after all, and same ambient conditions, no?!
> Did they consider locating them on the horizontal stabilizer, considering that the tail fuel very possibly would be the first we need to dump?
Hmmm... The tail contains about 22t max, if I remember correctly. However, in a situation that requires dumping you probably would want to dump more than that.
Now, you could pump parts of the wing tanks fuel through the aft fuselage to the THS ports. But what about flow rates? And what about the case of an UERF that in fact punctured the fuselage and severed the trim line? Then, jettison would be impossible.
I think it^s much easier and more reliable to put the ports on the wing. This is where the majority of the fuel is, this is where you have the powerful pumps. The vicinity of the engines seems to be no problem, and while I have to say that I understand your CG concerns:
I hardly remember any CG issues on the A330/A340s, and they even have a complex CG control system, i. e. aft and fwd xfers are possible in flight. (The A380 on the other hand only has a "bucket in the tail", similar to those B744s with a tail tank.).
I know of one significant issue once with trapped fuel in the THS, on an old A340 which does not have a proper xfer pump (relies on head pressure for fwd xfer which may not be sufficient under certain conditions).
Apart from that: Good reliability of the CG control system, redundancy in valves and control. No worries there.
Conclusion:
I think keeping the ports where they are is much simpler and also more reliable.
Cheers,
J.V.
(not a designer, just a poor little 145er
)
Last edited by jettison valve; 20th Nov 2010 at 16:39. Reason: Attempt no 10 to paste the URL!!!! It doesn^t like "blogspot" or what...?
OK BOAC appologized for even mentioning statistics
But this blame game stuff about who knew what and when and lawyereese talk fails to understand the imperfect engineering world we live in and the implied risk we take when the unexpected happens.
In spite of all the intelligence that we bring to the design history (statistics are hidden in there someplace) combinations of faults can come together to make a bad day. The regulations themselves can not force perfection but they can at least present a realistic approach that faults of any kind should be expected sometime, somewhere and as such we should address them as if they will happen if only at a surprised time. Isn't that why we put anti-locked brakes on a car?
Any designer and manufacturer of a jet engine knows full well that someday his engine will blow its guts out. He does his best to make sure it won't happen often and his regulator looks over his shoulder to make sure that he is doing his best.
But since history can repeat itself given enough time, the user of the product (the airplane manufacturer) does his best to mitigate the bad from the engine even though he has no idea of how or when it's going to happen (as we put air-bags in cars). Once again the regulator looks over the airplane guys shoulders to make sure that he is doing his best.
In spite of doing one's best, there are so many trades in risk going on here that even the mitigations of the consequences may not be relied 100% of the time (there's that pesky statistics again).
So we're back to the hard facts that something failed and it must be addressed in some fashion that is less likely to fail again.
The mitigation of the failure was sucessful to meet the objective that no catastrophy ocurred. In spite of this, new experience both good and bad is there to be learned and applied in a fashion to benefit future safety.
The details in all this are now in the provence of the investigators and I await their disclosure.
Predicting the details ahead of time is just speculation and the more that we do it the more that we blind ourselves from truly learning from facts rather than beliefs.
But this blame game stuff about who knew what and when and lawyereese talk fails to understand the imperfect engineering world we live in and the implied risk we take when the unexpected happens.
In spite of all the intelligence that we bring to the design history (statistics are hidden in there someplace) combinations of faults can come together to make a bad day. The regulations themselves can not force perfection but they can at least present a realistic approach that faults of any kind should be expected sometime, somewhere and as such we should address them as if they will happen if only at a surprised time. Isn't that why we put anti-locked brakes on a car?
Any designer and manufacturer of a jet engine knows full well that someday his engine will blow its guts out. He does his best to make sure it won't happen often and his regulator looks over his shoulder to make sure that he is doing his best.
But since history can repeat itself given enough time, the user of the product (the airplane manufacturer) does his best to mitigate the bad from the engine even though he has no idea of how or when it's going to happen (as we put air-bags in cars). Once again the regulator looks over the airplane guys shoulders to make sure that he is doing his best.
In spite of doing one's best, there are so many trades in risk going on here that even the mitigations of the consequences may not be relied 100% of the time (there's that pesky statistics again).
So we're back to the hard facts that something failed and it must be addressed in some fashion that is less likely to fail again.
The mitigation of the failure was sucessful to meet the objective that no catastrophy ocurred. In spite of this, new experience both good and bad is there to be learned and applied in a fashion to benefit future safety.
The details in all this are now in the provence of the investigators and I await their disclosure.
Predicting the details ahead of time is just speculation and the more that we do it the more that we blind ourselves from truly learning from facts rather than beliefs.
It is in the nature of the way I write. MEL'ed is exactly as you say. In this case, I use the acronym to emphasize that Qantas was taken "Out of the Loop". It was a Minimum constructed by the Authority, the AD served as an ad hoc MEL. With leased power, and RR in contact with the authority, Qantas was deaf and blind here. That is the part of my contracts rant I think is most important. For a virtually new powerplant to require such close scrutiny, and oversight, is unusual enough to have raised flags with Qantas, of course, they are not innocent here. It is this "blurring" of responsibilty in Aviation that has me upset, this "Plausible Deniability". To believe otherwise is to accept the Authority, The Manufacturer, and the Operator as blazing idiots. Not the case, so while there is much strutting and massaging of the Press, the really important question is hidden.
How the Hell did this happen; who needs to be prosecuted, fired, and fined to clear the decks of dangerous deadwood. This flight came within a hair of being lost at Sea. We discuss Money lost as if it is the fulcrum of the discussion. Shame on us all.
bear
How the Hell did this happen; who needs to be prosecuted, fired, and fined to clear the decks of dangerous deadwood. This flight came within a hair of being lost at Sea. We discuss Money lost as if it is the fulcrum of the discussion. Shame on us all.
bear
Press Releases from companies trying to protect their image with the flying public before the investigations are complete can't be relied upon.
Its all speculation.
Speculate all you want - it can be interesting - but I'm tempted to say shame on you for trying to insinuate it is more than just speculation.
It seems that your views on failure rates don't appear to take into account the role of maintenance checks in ensuring safety in mitigation of potential technical weaknesses. Is this right?
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lomapaseo
I agree with you when you state that engineering design is imperfect and also with the rest of your post.
In my previous posts on this thread with regard to contract law etc I was, for balance, pointing out that this area is a minefield, open to many intepertations.
I was also concerned that bearfoil was suggesting that criminal acts had taken place. I refer to his last post where he states "who needs to be prosecuted,fired,and fined to clear the decks of dangerous deadwood".
I would submit that to make such a statement you must be of the view that a criminal act has taken place. In my opinion none of us contributing to this thread have sufficent information to reach that view. Therefore in my opinion that comment is a red herring which detracts from the interesting technical debate that is taking place here.
I have gone on long enough about contract law etc and I hope that the technical debate continues.
Regards
Nick
Edit:JFZ90 I have just seen your last post and I agree with your sentiments.
I agree with you when you state that engineering design is imperfect and also with the rest of your post.
In my previous posts on this thread with regard to contract law etc I was, for balance, pointing out that this area is a minefield, open to many intepertations.
I was also concerned that bearfoil was suggesting that criminal acts had taken place. I refer to his last post where he states "who needs to be prosecuted,fired,and fined to clear the decks of dangerous deadwood".
I would submit that to make such a statement you must be of the view that a criminal act has taken place. In my opinion none of us contributing to this thread have sufficent information to reach that view. Therefore in my opinion that comment is a red herring which detracts from the interesting technical debate that is taking place here.
I have gone on long enough about contract law etc and I hope that the technical debate continues.
Regards
Nick
Edit:JFZ90 I have just seen your last post and I agree with your sentiments.
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bearfoil's not one to use two words when five will do. His verbosity is exceeded only by his clairvoyance which allows him judge and jury in matters of which he knows nowt.
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A long breath...... I believe I take a lot for granted here. I apologize. Maintenance prescribed as the result of an AD to mitigate a defect? Certainly that adds to the "Statistics". It improves the odds of a catastrophic event, by definition. I am constantly on about how Aviation is a compromise: IT IS, and always will be. Does that not signal an allowance for misstep, fault, or other in my opinions? If one does not see that, this post is wasted. I am passionate about Safety in Aviation, especially in Commercial Carriage, that is somehow to be disdained? "Merely a Flesh Wound".? Not so, This magnificent machine and its people were put in harm's way by a system that allowed a "waiver of care". "After the Fact"? OF COURSE!! Two FBW AB have drowned with loss of all. This was close, if you cannot see that, you have no business in the Profession. I am weary of the Tacit and Collective Pilot EGO, that turns a cheek, with a stiff lip, as if some heroism was involved in bringing people home. Bringing them safely home is the Mission, all failure is not acceptable. Does it happen? Do I need to continue to ask and answer basic concepts??
Legal: Every piece of data that is in public view condemns the current practice. Negligence can be indicted and charged as a crime, Does it exist? We'll see. Anything further is a waste of time, so those of you who rue this passion, let us agree to disagree. From whence comes this need to be casual? It doesn't paint one as professional, far from it, it suggests ignorance, imo.
Verbosity comes with investigative pursuit, and is a bad habit. It is sometimes used to protect one's interests in hostile territory, ask a lawyer. To add one thing. In a free Country, all public regulations to include ADs and waivers, etc. produced at the administrative level, are required to be made part of the PUBLIC RECORD "Working around" an AD, even if it "improves it", is not allowed, nor if it occurs, is it allowed to be kept secret.
best regards,
bear
Legal: Every piece of data that is in public view condemns the current practice. Negligence can be indicted and charged as a crime, Does it exist? We'll see. Anything further is a waste of time, so those of you who rue this passion, let us agree to disagree. From whence comes this need to be casual? It doesn't paint one as professional, far from it, it suggests ignorance, imo.
Verbosity comes with investigative pursuit, and is a bad habit. It is sometimes used to protect one's interests in hostile territory, ask a lawyer. To add one thing. In a free Country, all public regulations to include ADs and waivers, etc. produced at the administrative level, are required to be made part of the PUBLIC RECORD "Working around" an AD, even if it "improves it", is not allowed, nor if it occurs, is it allowed to be kept secret.
best regards,
bear
Last edited by bearfoil; 20th Nov 2010 at 19:22.
A long breath...... I believe I take a lot for granted here. I apologize. Maintenance prescribed as the result of an AD to mitigate a defect? Certainly that adds to the "Statistics". It improves the odds of a catastrophic event, by definition. I am constantly on about how Aviation is a compromise: IT IS, and always will be. Does that not signal an allowance for misstep, fault, or other in my opinions? If one does not see that, this post is wasted. I am passionate about Safety in Aviation, especially in Commercial Carriage, that is somehow to be disdained? "Merely a Flesh Wound".? Not so, This magnificent machine and its people were put in harm's way by a system that allowed a "waiver of care". "After the Fact"? OF COURSE!! Two FBW AB have drowned with loss of all. This was close, if you cannot see that, you have no business in the Profession. I am weary of the Tacit and Collective Pilot EGO, that turns a cheek, with a stiff lip, as if some heroism was involved in bringing people home. Bringing them safely home is the Mission, all failure is not acceptable. Does it happen? Do I need to continue to ask and answer basic concepts??
Legal: Every piece of data that is in public view condemns the current practice. Negligence can be indicted and charged as a crime, Does it exist? We'll see. Anything further is a waste of time, so those of you who rue this passion, let us agree to disagree. From whence comes this need to be casual? It doesn't paint one as professional, far from it, it suggests ignorance, imo.
Verbosity comes with investigative pursuit, and is a bad habit. It is sometimes used to protect one's interests in hostile territory, ask a lawyer.
best regards,
bear
Legal: Every piece of data that is in public view condemns the current practice. Negligence can be indicted and charged as a crime, Does it exist? We'll see. Anything further is a waste of time, so those of you who rue this passion, let us agree to disagree. From whence comes this need to be casual? It doesn't paint one as professional, far from it, it suggests ignorance, imo.
Verbosity comes with investigative pursuit, and is a bad habit. It is sometimes used to protect one's interests in hostile territory, ask a lawyer.
best regards,
bear
Not sure you've convinced me that you really understand the stats side in your post above, if anything quite the opposite, as I suspected.
By saying "Negligence....., does it exist, we'll see." - this confirms that you don't know.
It would be unprofessional in the extreme to infer negligence on the part of Rolls at this stage - but I get the impression you have done exactly that in earlier posts. You admit above that you don't know.
The only professional way to speculate is to recognise the a range of scenarios may infact exist - including the possibility that there has been no breach or negligence - just some new lessons to learn. If you don't know that, you don't belong in the business - it now seems likely you aren't in the business in any credible capacity.
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Firstly the construction of a single layer of atom thick graphene to contain an engine would cost more than the aircraft itself, it's done on nano scale.
Secondly, can you explain how you would prevent those lovely sheets of graphene and those really nice sp2 hybridized carbons from combining with some really nice van der Waals interactions with their adjacent sheets and forming graphite.
A good idea, but really lacking in knowledge.
Secondly, can you explain how you would prevent those lovely sheets of graphene and those really nice sp2 hybridized carbons from combining with some really nice van der Waals interactions with their adjacent sheets and forming graphite.
A good idea, but really lacking in knowledge.
Certification One HE Fragment
One single high energy fragment is considered from a certification requirement viewpoint. The damage assessment has established that the IPT disk released 3 different high energy fragments, resulting in some structural and systems damage, with associated ECAM warnings. Therefore the crew had to manage a dynamic situation....
....After the aircraft came to a stop, the reason engine 1 could not be shut down has been determined: 2 segregated wiring routes were cut by 2 out of the 3 individual disk debris....
....After the aircraft came to a stop, the reason engine 1 could not be shut down has been determined: 2 segregated wiring routes were cut by 2 out of the 3 individual disk debris....
The release trajectory can be calculated, with the impact regions being ascertained with some reliability, with or without historical data on failure modes. Roughly, the probability of a strike on a wing is going to be in the order of p=0.15-0.20, due to segmentation and the extreme imbalances that occur following initial failure resulting in short period for total release to occur, and minimal azimuthal shift (radial loading on the disk is in the order of 35k-50k g across the disc face, radial velocity ~ 1200 Rad, titanium shear strength ~75KSI... release period around 1ms or less... disc rotation during failure of 1 Rad). The probability of a strike on an adjacent engine is almost nil unless the engines are co-located, and airborne, there is again almost nil likelihood of a strike on an engine on the other wing from podded underwing installations.
The blades while initially high energy lose this rapidly, but have a greater spray region, with potential to do damage to lighter structure at a distance.