Nimrod crash in Afghanistan Tech/Info/Discussion (NOT condolences)
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Squidlord,
Its pleasing to see a balanced view for a change.
Nigegilb,
As usual, you are scaremongering by putting that report on the web. QQ were invited to Kinloss to provide an objective and independant study of the growing fuel leak problems that were giving rise to adverse operational capability. The QQ report did not mention that every one of the unacceptable leaks kept the aircraft on the ground until that leak was cured. This fact was not mentioned simply because it is a fundamental reason for the study: "Some important (role capable) jets are leaking, they cannot fly, they are limiting our capability. QQ do a study that we can act on, so we can get them flying again" Its nothing more than that: a very sensible project sponsored by the IPT.
Nobody was surprised that the wing leaked when a pod was fitted. Clearly the DA approved the concept of bolting a pod onto the wing of an old aircraft and would have done the calcs for stresses, etc. The only foreseen problem was the slight seepage from the wings, which is unacceptable near a pod.
You are making a mountain out of a molehill. Its not as though this is relevant to safety. As we have mentioned time and time again: if it leaks beyond acceptable limits (which are very tight) it doesn't fly. Therefore we met the airworthiness requirements to fly safely or not at all. We chose (through sound engineering policy) not to fly with those leaks and we still adhere to that policy. That report was required to provide guidance in engineering practices to alleviate availability problems; not highlight unsafe fuel leaks. We already knew the leaks were unacceptable for flight, we needed help in dealing with them.
Did you seek the permission of QQ to publish their work on the web?
Regards
Ed
Its pleasing to see a balanced view for a change.
Nigegilb,
As usual, you are scaremongering by putting that report on the web. QQ were invited to Kinloss to provide an objective and independant study of the growing fuel leak problems that were giving rise to adverse operational capability. The QQ report did not mention that every one of the unacceptable leaks kept the aircraft on the ground until that leak was cured. This fact was not mentioned simply because it is a fundamental reason for the study: "Some important (role capable) jets are leaking, they cannot fly, they are limiting our capability. QQ do a study that we can act on, so we can get them flying again" Its nothing more than that: a very sensible project sponsored by the IPT.
Nobody was surprised that the wing leaked when a pod was fitted. Clearly the DA approved the concept of bolting a pod onto the wing of an old aircraft and would have done the calcs for stresses, etc. The only foreseen problem was the slight seepage from the wings, which is unacceptable near a pod.
You are making a mountain out of a molehill. Its not as though this is relevant to safety. As we have mentioned time and time again: if it leaks beyond acceptable limits (which are very tight) it doesn't fly. Therefore we met the airworthiness requirements to fly safely or not at all. We chose (through sound engineering policy) not to fly with those leaks and we still adhere to that policy. That report was required to provide guidance in engineering practices to alleviate availability problems; not highlight unsafe fuel leaks. We already knew the leaks were unacceptable for flight, we needed help in dealing with them.
Did you seek the permission of QQ to publish their work on the web?
Regards
Ed
I, for one, found this report very helpful in explaining many of the comments on the thread. As it has been redacted and obtained under Freedom of Information, I think it is fair to say it is in the public domain. Would I also be correct in saying QinetiQ are the MoD’s appointed independent advisors and, as such, their opinions are actually informed opinions based on significant expertise and background knowledge? If I were MoD I’d hesitate before dismissing such a report.
As for scaremongering, there is an obvious counter in that this report would seem to be one of several key documents which informed the BoI’s opinion that the regulations had not been applied properly, leading to the Defence Secretary’s admission of liability. Against this background, the Coroner heard evidence that the aircraft had not been airworthy for many years and had little option but to give the verdict he did. Rather than rounding on nigegilb, whose credentials seem impeccable, perhaps we should step back and simply ask the question “Is the thrust of the report, and the conclusions drawn by the BoI and Defence Secretary, correct?” If so, then should any ire not be directed at those who brought about this situation, not those who seek to correct it?
It strikes me that many here, while wanting their tuppence worth on their own areas of expertise, are actually like-minded. Wouldn’t it be good if these combined energies could help solve the problems, instead of arguing over minor points of detail?
As for scaremongering, there is an obvious counter in that this report would seem to be one of several key documents which informed the BoI’s opinion that the regulations had not been applied properly, leading to the Defence Secretary’s admission of liability. Against this background, the Coroner heard evidence that the aircraft had not been airworthy for many years and had little option but to give the verdict he did. Rather than rounding on nigegilb, whose credentials seem impeccable, perhaps we should step back and simply ask the question “Is the thrust of the report, and the conclusions drawn by the BoI and Defence Secretary, correct?” If so, then should any ire not be directed at those who brought about this situation, not those who seek to correct it?
It strikes me that many here, while wanting their tuppence worth on their own areas of expertise, are actually like-minded. Wouldn’t it be good if these combined energies could help solve the problems, instead of arguing over minor points of detail?
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Edset, Kinloss has been taking hits on this report for months, I thought you of all people would see the sense in making it available for everybody at Kinloss to read. It was obtained under FOI and is, indeed in the public domain, or are you against the FOI Act as well?
As for seeking permission, I didn't publish it on the internet so I can't answer that one. I am disappointed by your reaction, some very experienced engineers working at Kinloss at the time were not even aware the report was being carried out and had not read it.
JFZ has taken a different view and it has certainly prompted comment from knowledgeable people. Perhaps JFZ should declare an interest? Anyone on this thread have any connections with Nimrod IPT? As for scaremongering, it is a factual report, you might like to re-visit your comments.
As you are back on thread would you also like to re-visit your comments regarding AAR?
"Despite the criticism of leadership, the technical aspect, ie "it is as safe as it needs to be" still stands. I re-iterate that its in the present tense. I believe the report is at its final stage. I haven't read it, but the rumour is that CAS's words remain correct: the Nimrod is safe enough for AAR. But, there is a growing feeling that due to intrusive media and public pressure, the technical factor in the decision may be overruled for political reasons. However, growing media and public attention to the troops taking fire on the ground may encourage the politicians to provide those lads with the best surveillance support the RAF has to offer. Its being held back at the moment for no good technical reason."
Six outstanding recommendations from QQ have not been dealt with but you state that AAR is safe, are you sticking to that statement and in doing so ignoring these six recs?
On another thread P-8A is being discussed this is the Multi Mission Aircraft (MMA), B737 conversion for US Navy. Thought I would post this;
Feldman says: "It is not built for survivability as a commercial aircraft, so we have done significant live-fire testing and are incorporating the results into the design." A lot of the work involves the fuel system: protecting or relocating components double-wall tank liners sense and drain systems and dry-bay fire protection. "These areas have been dealt with and there are no outstanding vulnerability concerns," he says. Using a building-block approach, Boeing has conducted life-fire tests on critical areas of the airframe using surrogate structures. This has resulted in selection of an inerting system to protect the dry-bay areas around the cargo-bay fuel tanks.
Err, you won't be getting this in MRA4. Fit for purpose? I think not, neither do I think the MoD/IPT is learning lessons.
As for seeking permission, I didn't publish it on the internet so I can't answer that one. I am disappointed by your reaction, some very experienced engineers working at Kinloss at the time were not even aware the report was being carried out and had not read it.
JFZ has taken a different view and it has certainly prompted comment from knowledgeable people. Perhaps JFZ should declare an interest? Anyone on this thread have any connections with Nimrod IPT? As for scaremongering, it is a factual report, you might like to re-visit your comments.
As you are back on thread would you also like to re-visit your comments regarding AAR?
"Despite the criticism of leadership, the technical aspect, ie "it is as safe as it needs to be" still stands. I re-iterate that its in the present tense. I believe the report is at its final stage. I haven't read it, but the rumour is that CAS's words remain correct: the Nimrod is safe enough for AAR. But, there is a growing feeling that due to intrusive media and public pressure, the technical factor in the decision may be overruled for political reasons. However, growing media and public attention to the troops taking fire on the ground may encourage the politicians to provide those lads with the best surveillance support the RAF has to offer. Its being held back at the moment for no good technical reason."
Six outstanding recommendations from QQ have not been dealt with but you state that AAR is safe, are you sticking to that statement and in doing so ignoring these six recs?
On another thread P-8A is being discussed this is the Multi Mission Aircraft (MMA), B737 conversion for US Navy. Thought I would post this;
Feldman says: "It is not built for survivability as a commercial aircraft, so we have done significant live-fire testing and are incorporating the results into the design." A lot of the work involves the fuel system: protecting or relocating components double-wall tank liners sense and drain systems and dry-bay fire protection. "These areas have been dealt with and there are no outstanding vulnerability concerns," he says. Using a building-block approach, Boeing has conducted life-fire tests on critical areas of the airframe using surrogate structures. This has resulted in selection of an inerting system to protect the dry-bay areas around the cargo-bay fuel tanks.
Err, you won't be getting this in MRA4. Fit for purpose? I think not, neither do I think the MoD/IPT is learning lessons.
Last edited by nigegilb; 26th Jun 2008 at 12:39.
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Look guys I know this whole issue has raised a lot of heat on both sides but it would surely be more sensible and helpful to the debate if people on both sides stopped throwing pies at each other and simply discussed the points raised in the report. It has been released under FoI, it has been reported on in the press, I'm not sure that putting it up on the internet is a major issue. Wouldnt it be better and more helpful to the debate to make reasoned arguments on the points in the report and why they reflect either an unacceptable situation or a situation that is actually no problem.
I believe that these failings are to some extent endemic in MoD air safety management in general. Efforts are being made at senior levels within the MoD to address these failings and I believe that we are likely to see the biggest changes in MoD safety management since the Safety Case concept and culture was adopted (in the early-mid 90s, I think).
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Dear Squidlord, welcome to the debate.
You said,
Can you give an example of another Nimrod related report?
DV
You said,
For what it is worth, there is nothing remotely unusual about QQ issueing a draft report for comment. It happens all the time
DV
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Dear Squidlord, welcome to the debate.
You said,
Quote:
For what it is worth, there is nothing remotely unusual about QQ issueing a draft report for comment. It happens all the time
Can you give an example of another Nimrod related report?
DV
You said,
Quote:
For what it is worth, there is nothing remotely unusual about QQ issueing a draft report for comment. It happens all the time
Can you give an example of another Nimrod related report?
DV
DV
Can you?
MHAGE
Can you?
MHAGE
Nimrod Aircraft
Angus Robertson: To ask the Secretary of State for Defence what the cost of QinetiQ's consultations on Nimrod were over the last three years. [209727]
Mr. Bob Ainsworth: The cost of work relating to Nimrod aircraft carried out by QinetiQ over the last three financial years was £26.1 million.
Angus Robertson: To ask the Secretary of State for Defence what the cost of QinetiQ's consultations on Nimrod were over the last three years. [209727]
Mr. Bob Ainsworth: The cost of work relating to Nimrod aircraft carried out by QinetiQ over the last three financial years was £26.1 million.
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Mighty Hunter AGE
Perhaps I did not make myself clear. The point being made was that "there is nothing remotely unusual about QQ issueing a draft report for comment" I think there is. Of all the QQ reports that I have obtain, only one has been issued as a draft for comment, and that is the Oct 2007 report.
So in answer to your question, I have to reply no. Of course there have been several high profile Nimrod reports, such as the 2006 report mentioned by Nigegil, the combustion analysis report, several seal reports, a report on zonal analysis etc. None of these indicate that they have been issued in draft form for comment.
DV
Perhaps I did not make myself clear. The point being made was that "there is nothing remotely unusual about QQ issueing a draft report for comment" I think there is. Of all the QQ reports that I have obtain, only one has been issued as a draft for comment, and that is the Oct 2007 report.
So in answer to your question, I have to reply no. Of course there have been several high profile Nimrod reports, such as the 2006 report mentioned by Nigegil, the combustion analysis report, several seal reports, a report on zonal analysis etc. None of these indicate that they have been issued in draft form for comment.
DV
Draft documents
DV
I assume that you are referring to the Word version and change history information to infer the issue status of the QQ documents. I have 2 points to make: one, it is known that this history is stored in the Word document and there are methods to prevent such information 'leaking' out (obviously not done in this case). Two, it is common within the MOD (and no doubt other organizations - government and commercial) for reports to be issued in draft to allow early visibility to the sponsor and to allow obvious errors to be corrected before a report is published (and paid for). I do not mean that unsavoury statements are removed or toned down (although this can happen), but to ensure that it is factually correct. There is nothing sinister in this practice - although I am sure you will find one.
I assume that you are referring to the Word version and change history information to infer the issue status of the QQ documents. I have 2 points to make: one, it is known that this history is stored in the Word document and there are methods to prevent such information 'leaking' out (obviously not done in this case). Two, it is common within the MOD (and no doubt other organizations - government and commercial) for reports to be issued in draft to allow early visibility to the sponsor and to allow obvious errors to be corrected before a report is published (and paid for). I do not mean that unsavoury statements are removed or toned down (although this can happen), but to ensure that it is factually correct. There is nothing sinister in this practice - although I am sure you will find one.
Squidlord. Well balanced post. Your analysis is very compelling and points out many holes in the some of the conclusions being drawn (or jumped to) here.
I've resisted criticising the QQ report in the way you have, but the weaknesses/inconsistences you point out are spot on. In their defence you could argue they would not have expected particular phrases to have been latched onto in the way they have without consideration of the wider picture you outline.
Mick - does this shed any new perspectives on your April Sunday Times article on how Des misled the house of Nimrod safety and ALARP? Do you perhaps consider it is possible, given Squidlords analysis above, that he didn't?
This is the real irony isn't it. The IPT commissions an independant investigation into fuel leaks well before 230s loss, and you could argue is therefore clearly taking proactive steps to try and find out why this is the case and what it can do to fix it.
In terms of the FOI status of the report - I assume the red text was added after it was released under FOI; this emphasises QQs rights that still therefore apply. So technically you are not allowed to publish on the net without QQs permission.
Nige - I have no connection with Nimrod in any way.
I've resisted criticising the QQ report in the way you have, but the weaknesses/inconsistences you point out are spot on. In their defence you could argue they would not have expected particular phrases to have been latched onto in the way they have without consideration of the wider picture you outline.
Mick - does this shed any new perspectives on your April Sunday Times article on how Des misled the house of Nimrod safety and ALARP? Do you perhaps consider it is possible, given Squidlords analysis above, that he didn't?
As usual, you are scaremongering by putting that report on the web. QQ were invited to Kinloss to provide an objective and independant study of the growing fuel leak problems that were giving rise to adverse operational capability. The QQ report did not mention that every one of the unacceptable leaks kept the aircraft on the ground until that leak was cured. This fact was not mentioned simply because it is a fundamental reason for the study: "Some important (role capable) jets are leaking, they cannot fly, they are limiting our capability. QQ do a study that we can act on, so we can get them flying again" Its nothing more than that: a very sensible project sponsored by the IPT.
In terms of the FOI status of the report - I assume the red text was added after it was released under FOI; this emphasises QQs rights that still therefore apply. So technically you are not allowed to publish on the net without QQs permission.
Nige - I have no connection with Nimrod in any way.
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Squidlord,
a thought provoking and interesting entry to the discussion. I would like to emphasise however that the points from my own post that you have quoted were very much questions, rather than statements - struggling to understand it all myself, I have no engineering expertise unless feeding very strong coffee and curry to the FLt Eng counts - so my 5 points were an invitation to others to comment, as in 'have I got this right?' JFZ90 promptly added a bit, and right or wrong he (?) made me see there was (possibly) a time dimension I hadn't really considered before - my basic problem being I keep expecting there to be a set of rules by which a system is declared ok or not. Instead it seems to be a mental Gordian knot.
For what it's worth, and to avoid anyone mentally placing me in one camp or the other incorrectly, my thoughts run thus:
20-30 years ago we used to comment on Nimrods being exceptionally safe - every time you went through the OCU or NCF etc people would queue up to tell you 'we should have lost 2 by now' or similar. Had AAR never been fitted I suspect the Nimrod would have exited service renowned for its safety record...achieved, at times, by a mere whisker, admittedly. I imagine everyone who has ever flown on them has a fair stock of 'almost' stories.
My feeling is that sometime post '82 an approach of 'it's been okay so far' was substituted for rigorous safety procedures, and that has been exacerbated by declining experience levels in just about every trade, including aircrew. No aspersions here at all on competence, but experience and numbers do tend to count. Take away the money as well and it's a recipe for disaster. We ALL saw that coming though, frankly. EVEYONE (well, almost) tells you how much better it all used to be.....they did that in 1925 too.
AAR was a Heath-Robinson lash up in 82. In my OPINION it clearly wasn't rigorously tested at any point after the dust settled...otherwise, my brain says, we'd have had a good idea of how big a pressure spike the system could safely handle, for one thing. In 1982 it was forgivable, we needed it NOW - personally I don't think that an AAR system failure almost 25 years later says much good of the safety management of Nimrod, surely in all that time it could have been given a thorough going over to check it was really okay?
ALARP - I believe I get the basic idea, I also believe (perhaps wrongly) it is possible to fly the aircraft safely without it being ALARP, provided AAR isn't performed (for example) and perhaps other procedural changes are enforced. I can readily accept that some of those changes might not become public knowledge for a variety of reasons.
Overall, the RAF and MOD let some old crewmates and their families down, as usual it was the servicemen, and their families, who paid for that. I think it is up to the RAF and MOD to make it very obvious they are doing all that they can to turn this around - my OPINION post inquest is that they are still more determined to hide problems than address them.
Dave
a thought provoking and interesting entry to the discussion. I would like to emphasise however that the points from my own post that you have quoted were very much questions, rather than statements - struggling to understand it all myself, I have no engineering expertise unless feeding very strong coffee and curry to the FLt Eng counts - so my 5 points were an invitation to others to comment, as in 'have I got this right?' JFZ90 promptly added a bit, and right or wrong he (?) made me see there was (possibly) a time dimension I hadn't really considered before - my basic problem being I keep expecting there to be a set of rules by which a system is declared ok or not. Instead it seems to be a mental Gordian knot.
For what it's worth, and to avoid anyone mentally placing me in one camp or the other incorrectly, my thoughts run thus:
20-30 years ago we used to comment on Nimrods being exceptionally safe - every time you went through the OCU or NCF etc people would queue up to tell you 'we should have lost 2 by now' or similar. Had AAR never been fitted I suspect the Nimrod would have exited service renowned for its safety record...achieved, at times, by a mere whisker, admittedly. I imagine everyone who has ever flown on them has a fair stock of 'almost' stories.
My feeling is that sometime post '82 an approach of 'it's been okay so far' was substituted for rigorous safety procedures, and that has been exacerbated by declining experience levels in just about every trade, including aircrew. No aspersions here at all on competence, but experience and numbers do tend to count. Take away the money as well and it's a recipe for disaster. We ALL saw that coming though, frankly. EVEYONE (well, almost) tells you how much better it all used to be.....they did that in 1925 too.
AAR was a Heath-Robinson lash up in 82. In my OPINION it clearly wasn't rigorously tested at any point after the dust settled...otherwise, my brain says, we'd have had a good idea of how big a pressure spike the system could safely handle, for one thing. In 1982 it was forgivable, we needed it NOW - personally I don't think that an AAR system failure almost 25 years later says much good of the safety management of Nimrod, surely in all that time it could have been given a thorough going over to check it was really okay?
ALARP - I believe I get the basic idea, I also believe (perhaps wrongly) it is possible to fly the aircraft safely without it being ALARP, provided AAR isn't performed (for example) and perhaps other procedural changes are enforced. I can readily accept that some of those changes might not become public knowledge for a variety of reasons.
Overall, the RAF and MOD let some old crewmates and their families down, as usual it was the servicemen, and their families, who paid for that. I think it is up to the RAF and MOD to make it very obvious they are doing all that they can to turn this around - my OPINION post inquest is that they are still more determined to hide problems than address them.
Dave
Dave,
Some quick thoughts:
AAR itself is not potentially the most significant issue with respect to the loss of 230. The ignition source (hot pipes) were the most significant issue, and stem from decisions made long ago (pre 82 I think).
I may have this wrong, but the main issue with AAR seems to be that the system - system issues are not fully understand, there have been some strange occurances leading to leaks, and on that basis, even though there is no longer a clear/obvious ignition source/risk, it is not being cleared. It must be remembered that leaks on ANY aircraft are not categorised as "improbable" and hence all aircraft designs should be able to tolerate leaks. Even new aircraft that only leak rarely, still might leak - and hence to be safe must be immediately imperilled by such leaks. Despite this, the decision to suspend AAR is perhaps understandable.
The issue with the rigour of the safety procedures is that they were infact not as good many years ago. Things have moved on and analysis techniques, faliure mode understanding and processes now are much much better. The interesting issue is the fact that increasingly "better" approaches (including the adoption of saftey cases) have failed to spot problems that have haboured within this legacy system, without biting for many years. It is likely as you say that the "its been alright for years" mindset may have degraded the rigour with which more modern, best practice analyses have been applied. This is actually a human factors issue - its human nature - optimism bias if you like.
Some quick thoughts:
AAR itself is not potentially the most significant issue with respect to the loss of 230. The ignition source (hot pipes) were the most significant issue, and stem from decisions made long ago (pre 82 I think).
I may have this wrong, but the main issue with AAR seems to be that the system - system issues are not fully understand, there have been some strange occurances leading to leaks, and on that basis, even though there is no longer a clear/obvious ignition source/risk, it is not being cleared. It must be remembered that leaks on ANY aircraft are not categorised as "improbable" and hence all aircraft designs should be able to tolerate leaks. Even new aircraft that only leak rarely, still might leak - and hence to be safe must be immediately imperilled by such leaks. Despite this, the decision to suspend AAR is perhaps understandable.
The issue with the rigour of the safety procedures is that they were infact not as good many years ago. Things have moved on and analysis techniques, faliure mode understanding and processes now are much much better. The interesting issue is the fact that increasingly "better" approaches (including the adoption of saftey cases) have failed to spot problems that have haboured within this legacy system, without biting for many years. It is likely as you say that the "its been alright for years" mindset may have degraded the rigour with which more modern, best practice analyses have been applied. This is actually a human factors issue - its human nature - optimism bias if you like.
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Squidlord,
I haven't yet gone through the report but one of the points you make is not quite correct.
Doesn't actually hold.
If some thing is "acceptable", it doesn't mean that the risks are ALARP, it means that the risks can be accepted, ie only that they are not "unacceptable" - the key phrase that an IPT doesn't want to hear. A bit like they don't want to hear the phrase "Release to Service is not recommended".
sw
I haven't yet gone through the report but one of the points you make is not quite correct.
If QQ are saying that the risks are (currently) "acceptable", then they are saying they are ALARP.
If some thing is "acceptable", it doesn't mean that the risks are ALARP, it means that the risks can be accepted, ie only that they are not "unacceptable" - the key phrase that an IPT doesn't want to hear. A bit like they don't want to hear the phrase "Release to Service is not recommended".
sw
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From the government Freedom of Information website
"Copyright and restrictions
The Freedom of Information Act does not place restrictions on how you may use the information you receive under it. However, the Act does not transfer copyright in any information supplied under it. If you plan to reproduce the information you receive, you should ensure that you will not be breaching anyone's copyright by doing so."
Nige, understand your frustration and why you felt compelled to provide a link to the QQ report but you may find yourself in a bit of bovver if they decide to pursue it.
The Freedom of Information Act does not place restrictions on how you may use the information you receive under it. However, the Act does not transfer copyright in any information supplied under it. If you plan to reproduce the information you receive, you should ensure that you will not be breaching anyone's copyright by doing so."
Nige, understand your frustration and why you felt compelled to provide a link to the QQ report but you may find yourself in a bit of bovver if they decide to pursue it.
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SFO,
that'd guarantee a huge shot to foot I suspect - which, admittedly, HAS tended to be the RAF PR dept's primary target for longer than I care to remember.
JFZ - I get your point re ignition, but I wouldn't blame that rather than the fuel leak. To my mind there was a source of ignition present for a long time, it didn't cause a fire because fuel wasn't also present. Unless I'm mistaken, and allowing for the absence of complete certainty in all this, the actual catalyst would appear to be the tanker type - as previous tankers used, such as the Victor, VC10 and Herc, didn't produce the same pressures... a case of it all actually being unsafe for years I suspect, but it was only when the final piece fell into place that the clock started to tick because finally pressure spikes started to occur that exceeded the systems ability to cope - and nobody seems to have known what pressures were being reached, and what the safe limit the system could handler were. (For anyone wishing to howl at this last sentence, I'm suggesting that both pieces of info were essential for safe operation, and that they weren't actually known - it was just assumed that everything would still go okay).
That may well all be a simplification, or just plain wrong...as I said, I too am struggling to understand it all.
that'd guarantee a huge shot to foot I suspect - which, admittedly, HAS tended to be the RAF PR dept's primary target for longer than I care to remember.
JFZ - I get your point re ignition, but I wouldn't blame that rather than the fuel leak. To my mind there was a source of ignition present for a long time, it didn't cause a fire because fuel wasn't also present. Unless I'm mistaken, and allowing for the absence of complete certainty in all this, the actual catalyst would appear to be the tanker type - as previous tankers used, such as the Victor, VC10 and Herc, didn't produce the same pressures... a case of it all actually being unsafe for years I suspect, but it was only when the final piece fell into place that the clock started to tick because finally pressure spikes started to occur that exceeded the systems ability to cope - and nobody seems to have known what pressures were being reached, and what the safe limit the system could handler were. (For anyone wishing to howl at this last sentence, I'm suggesting that both pieces of info were essential for safe operation, and that they weren't actually known - it was just assumed that everything would still go okay).
That may well all be a simplification, or just plain wrong...as I said, I too am struggling to understand it all.
Nige, understand your frustration and why you felt compelled to provide a link to the QQ report but you may find yourself in a bit of bovver if they decide to pursue it.
Dave,
Whilst that is true, the emphasis must be on the big NO NO being an ignition source. This was totally unacceptable in the aircraft design. Fuel as a liquid has a habit of getting in places it shouldn't, so you must take that into account in aircraft design and make attempts to ensure it can do no harm if it does. This is why you have to blame the ignition source, not the fuel. To put it in probability terms, you cannot preclude a leak from happening during the life of an aircraft by any stretch of the imagination - hence this shows that ignition sources must be absolutely totally avoided where fuel can come into contact with one otherwise you could never prove it met the required 10-7 hull loss rate (which is basically similar to saying never happens during an aircraft life) and hence could never be certified.
I'm not saying leaks are not a bad thing, just that you can't totally eliminate them, hence you MUST address the other risks.
To my mind there was a source of ignition present for a long time, it didn't cause a fire because fuel wasn't also present.
I'm not saying leaks are not a bad thing, just that you can't totally eliminate them, hence you MUST address the other risks.
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Squidlord
Sorry, I can not agree. If you look up "acceptable" in the Concise Oxford Dictionary it say that it means "tolerable". So we are back to square one. It is just that "acceptable" gives a better (but false) impression of safety, as does "tolerably safe".
"Tolerably safe" may be a definition used among the IPT's, and it is my belief that that is where it came from. If you read the QQ GSN report, you will note that goals are set for systems to be "Broadly Acceptable, or Tolerable and ALARP" because QinetiQ, being a professional organisation, knows that is the standard set for a system to be safe. Nowhere in the body of the report do they talk about systems being "tolerably safe"
You mention Def Stan 00-56, can you tell me where the terms "acceptable" and "tolerably safe" are defined in that document?
DV
If QQ are saying the risk are currently "acceptable" then they are saying they are ALARP
"Tolerably safe" may be a definition used among the IPT's, and it is my belief that that is where it came from. If you read the QQ GSN report, you will note that goals are set for systems to be "Broadly Acceptable, or Tolerable and ALARP" because QinetiQ, being a professional organisation, knows that is the standard set for a system to be safe. Nowhere in the body of the report do they talk about systems being "tolerably safe"
You mention Def Stan 00-56, can you tell me where the terms "acceptable" and "tolerably safe" are defined in that document?
DV
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So this entire thread and discussion is down to a meaning in the English dictionary when we refer to Tolerable or acceptable taken in the worng way ?
I can probably understand why they use the word Safe now , acceptable or tolerable are words that have been taken out of context it would seem.
This is the problem when you are dealing with law cases , screwing around of words can paint a whole diffrent picture. Good spot DV
I can probably understand why they use the word Safe now , acceptable or tolerable are words that have been taken out of context it would seem.
This is the problem when you are dealing with law cases , screwing around of words can paint a whole diffrent picture. Good spot DV