Helicopter crash off the coast of Newfoundland - 18 aboard, March 2009
Codger:
Nah, that's not what I was getting at.
1) FAR Part 29.927 says that main transmissions of helicopters certified under this part must have a 30-minute operational capability after "loss of lubricant."
2) Sikorsky's S-92 main transmission fails to meet that requirement in 2002.
3) FAR 29.927 allows that "unless such failures are extremely remote," then you don't have to have the 30-minute capability.
4) Sikorsky convinces the FAA that the transmission oil cooler and its associated lines are the *only* area that could result in a leak and loss of lubricant.
5) FAA buys off on SAC's bogus bypass system "workaround."
6) Subsequent events demonstrate that Sikorsky's initial contention that the oil cooler and lines were the *only* source of a leak were, well, inaccurate.
7) Ergo, the S-92 main transmission admittedly does not meet either the letter or spirit of FAR 29.927, despite the workaround.
Seems pretty simple to me. If an aircraft...any aircraft...so blatantly fails to meet its design certification criteria, then shouldn't its Certificate of Airworthiness be...you know...um...revoked?
I'm just sayin'.
Somewhere there is a large Greek man walking around, occasionally flinching uncontrollably at the memory of the bullet he dodged.
I don't know why the CofA hasn't been pulled or if it should be pulled... But if you think that any manufacturer of aircraft puts stuff out there for us to drive knowing that there's something in there that will kill us then that's a whole other deal.
1) FAR Part 29.927 says that main transmissions of helicopters certified under this part must have a 30-minute operational capability after "loss of lubricant."
2) Sikorsky's S-92 main transmission fails to meet that requirement in 2002.
3) FAR 29.927 allows that "unless such failures are extremely remote," then you don't have to have the 30-minute capability.
4) Sikorsky convinces the FAA that the transmission oil cooler and its associated lines are the *only* area that could result in a leak and loss of lubricant.
5) FAA buys off on SAC's bogus bypass system "workaround."
6) Subsequent events demonstrate that Sikorsky's initial contention that the oil cooler and lines were the *only* source of a leak were, well, inaccurate.
7) Ergo, the S-92 main transmission admittedly does not meet either the letter or spirit of FAR 29.927, despite the workaround.
Seems pretty simple to me. If an aircraft...any aircraft...so blatantly fails to meet its design certification criteria, then shouldn't its Certificate of Airworthiness be...you know...um...revoked?
I'm just sayin'.
Somewhere there is a large Greek man walking around, occasionally flinching uncontrollably at the memory of the bullet he dodged.
FH1100 - unfortunately the 18 guys on board didn't get to dodge that same bullet - I wonder if he sleeps at night thinking about it?
Sven
That might be true if the oil filter were the only possible source of oil loss from the MGB. Unfortunately its not - as has already been suggested, there are other weak points such as entry/exit points of drive shafts, and of course the possibility of a crack in a lower region of the MGB casing, which has happened plenty on the 92 MGB already (fortunately not large enough to release significant quantity of oil so far.)
But lets not lose the plot here, whilst the 92 clearly doesn't meet the 29.927 and so technically should lose its certification, neither do lots of other helicopters that fly around carrying oil workers over hostile seas, simply because they were certified before 29.927 existed in its current form - in the UK thats pretty much everything apart from the 225 and 139.
As people are saying, 30 mins dry run time doesn't necessarily stop a ditching (though here in the N Sea you are pretty much always within 30 mins of somewhere to land) and as Robert Decker himself said, what is of primary importance is to stop the helicopter ending up in the sea in the first place. Therefore concentration should be on preventing the oil loss etc in the first place, rather than what you are going to do once its all gone.
So I don't think the S92s should all be grounded pending compliance, however it is especially gaulling to consider the arrogance by which Sikorsky proclaimed the S92 to be the safest helicopter in the world whilst at the same time they were in full knowledge of its failure to comply with the spirit of 29.927.
And since the safety of any helicopter hangs by a tenous thread, any time a manufacturer gets arrogant (which implies complacency), that should be a danger sign!
HC
That might be true if the oil filter were the only possible source of oil loss from the MGB. Unfortunately its not - as has already been suggested, there are other weak points such as entry/exit points of drive shafts, and of course the possibility of a crack in a lower region of the MGB casing, which has happened plenty on the 92 MGB already (fortunately not large enough to release significant quantity of oil so far.)
But lets not lose the plot here, whilst the 92 clearly doesn't meet the 29.927 and so technically should lose its certification, neither do lots of other helicopters that fly around carrying oil workers over hostile seas, simply because they were certified before 29.927 existed in its current form - in the UK thats pretty much everything apart from the 225 and 139.
As people are saying, 30 mins dry run time doesn't necessarily stop a ditching (though here in the N Sea you are pretty much always within 30 mins of somewhere to land) and as Robert Decker himself said, what is of primary importance is to stop the helicopter ending up in the sea in the first place. Therefore concentration should be on preventing the oil loss etc in the first place, rather than what you are going to do once its all gone.
So I don't think the S92s should all be grounded pending compliance, however it is especially gaulling to consider the arrogance by which Sikorsky proclaimed the S92 to be the safest helicopter in the world whilst at the same time they were in full knowledge of its failure to comply with the spirit of 29.927.
And since the safety of any helicopter hangs by a tenous thread, any time a manufacturer gets arrogant (which implies complacency), that should be a danger sign!
HC
Sven
We may have been at cross-purposes here, I thought you were referring to the Oil Filter inspection (if there is one?) but perhaps you were referring to the feet cracking inspection? If so, these are specific inspections of the specific parts, the latter not being related to loss of oil (rather to loss of the entire MGB), and of course the best way to notice a problem is to see oil all over the side of the helicopter after landing. So really the point is, can such a fault develop so as to lose all the oil during the course of 1 flight. Clearly with the oil filter the answer was yes, but as to other possible causes we can't be sure but perhaps its unwise to rule it out.
HC
We may have been at cross-purposes here, I thought you were referring to the Oil Filter inspection (if there is one?) but perhaps you were referring to the feet cracking inspection? If so, these are specific inspections of the specific parts, the latter not being related to loss of oil (rather to loss of the entire MGB), and of course the best way to notice a problem is to see oil all over the side of the helicopter after landing. So really the point is, can such a fault develop so as to lose all the oil during the course of 1 flight. Clearly with the oil filter the answer was yes, but as to other possible causes we can't be sure but perhaps its unwise to rule it out.
HC
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Sven,
A Sikorsky rep. was recently quoted ""Analysis shows the aircraft can operate safely for a minimum of 10 hours, even assuming a full mount fracture and resulting worst-case stresses " Jackson said.
He said the company has advised all operators worldwide to visually inspect the footings every 10 hours."
Surely the 10 hours has been deemed to be a very conservative time frame for the time from possible detection of a defect (through this form of inspection) to the time of failure. Somebody would have done a calculation/estimation. To me the 10 h seems VERY conservative indeed.
He said the company has advised all operators worldwide to visually inspect the footings every 10 hours."
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I don't know what is the right way to go here, but my question is as follow. Somebody mentioned 138 000hrs for the 92 fleet now-how many MGB incidences have we had on the MGB of the 92 in that time and how many of them lead to a unscheduled landing?
If I apply the regulations that prevent me from using something like a single engine 350B3/EC130 in Europe and Britain due to the probability of a engine failure leading to a forced landing I wonder how many Arriel 2B1 failures have occured in 138 000 hours of the 350B3/EC130 fleet leading to a unscheduled landing? Anyone with figures use the worse data you can find out of the total fleet hours which I think is close to 2 million hrs, but i'm not sure.
If we find that more engine failures occured, i stand corrected and apoligise. If we find that less engine failures occured, surely I can use my single engine B3/130 on the basis of "remote possibility" vs MGB failure on a 92?
Stupid question but it puzzles me how this is possible?
If I apply the regulations that prevent me from using something like a single engine 350B3/EC130 in Europe and Britain due to the probability of a engine failure leading to a forced landing I wonder how many Arriel 2B1 failures have occured in 138 000 hours of the 350B3/EC130 fleet leading to a unscheduled landing? Anyone with figures use the worse data you can find out of the total fleet hours which I think is close to 2 million hrs, but i'm not sure.
If we find that more engine failures occured, i stand corrected and apoligise. If we find that less engine failures occured, surely I can use my single engine B3/130 on the basis of "remote possibility" vs MGB failure on a 92?
Stupid question but it puzzles me how this is possible?
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Mars, that is my point. That is why I asked how many incidents have we had on the MGB associated with unscheduled landings. If Cougar was not the only one (but sadly the most tragic), then my point is that if the fleet hours is 138 000hrs and if there were more incidents then the MGB must also be classified as "reasonably probable" until it can beat the 1:100 000 ratio? Isn't that a safety ratio used to increase safe operations by illiminating the risk? What is the 92 risk ratio then on the MGB currently? Maybe that should be the drive factor to fix the problems instead of concentrating on paragraphs that has been proven to be open to interpretation? There is very seldom 2 right answers in maths
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victorpapa,
Not a stupid question, in fact very pertinent as to concerns over how these probability calculations are done.
If you do a calculation prior to entry into service, then in operation there is an occurrance and you take some form of corrective action, followed by another probability assessment, can you now discount that occurrance (as some seem to believe) when recalculating probability ?
Or, in simpler terms, if something happens, and you fix it, but it happens again, (either due to the same or different cause/s), do all the flags start to go up, or can you say I'll fix it and continue on with the same level of probability as prior to the occurrance ?
Not a stupid question, in fact very pertinent as to concerns over how these probability calculations are done.
If you do a calculation prior to entry into service, then in operation there is an occurrance and you take some form of corrective action, followed by another probability assessment, can you now discount that occurrance (as some seem to believe) when recalculating probability ?
Or, in simpler terms, if something happens, and you fix it, but it happens again, (either due to the same or different cause/s), do all the flags start to go up, or can you say I'll fix it and continue on with the same level of probability as prior to the occurrance ?
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madrock, tks for getting my point. Why is it simple for engines and not for MGB's and there is no getting around the engine rule so why on something as critical as the MGB?
A Sikorsky rep. was recently quoted ""Analysis shows the aircraft can operate safely for a minimum of 10 hours, even assuming a full mount fracture and resulting worst-case stresses " Jackson said.
It's kind of funny...in a way. SAC is using the 10-hour inspection as a smoke screen. I might remind everyone that no matter how often you inspect a trans for cracks, if an unexpected one *does* occur in flight and all the juice leaks out, the pilots and passengers still only have about 10 minutes to get 'er on the ground. What good is your 10-hour inspection then? Were the cracks in the attachment bolts of Cougar's transmission oil filter detectable within 10 hours of them failing?
The 10-hour inspection does ABSOLUTELY NOTHING with respect to FAR 29.927. Eyewash. That's all it is.
The 10-hour inspection does ABSOLUTELY NOTHING with respect to FAR 29.927. Eyewash. That's all it is.
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FH1100pilot, just to try and clarify, as I think a fair bit of confusion is slipping in - to the best of my knowledge, the 10 hour inspection is on the mounting feet of the MGB, not the oil filter housing studs. In fact the inspection has nothing to do with the filter housing as that particular fault has now been "cleared" with modification, however they are still subject to regular inspection and monitoring. The mounting cracking is an entirely different issue and not to be confused with the shearing of the retaining studs on the oil filter housing, the believed cause of the Cougar accident. I am pretty sure we have been round this a couple of times now. The main difference as I see it is that inspection of the mounting feet will very likely detect a crack or weakness before it manifests itself in a catastrophic failure, and the 10 hours is a realistic and practical approach. The issue with the filter housing studs, was that of a material failure, and deemed that the use of titanium instead of steel was a likely design flaw, and weakness, therefore inspection of this area would have been of little use.
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One of the lingering issues following on the March accident seems to be why, after the Broome incident, was there such an apparent delay allowed before the problem had to be addressed in the field by means of the bolt changeout.
Now we have a MGB mounting lug that has had cracks appearing, first noticed at the beginning of this year, and as I understand it, the cause has not yet been determined.
The OEM has however stated "Analysis shows the aircraft can operate safely for a minimum of 10 hours, even assuming a full mount fracture and resulting worst-case stresses". I suppose one can probably assume this is where the "10 hours" came from in the current inspection interval.
Even if you have absolutely no doubt whatsoever that the manufacturer was able to replicate all possible known full mount fracture and resultant worst-case stress scenarios during their analysis and that 10 hours is the number, given the potential consequences if further damage were to occur after one mount had been fully fractured, why on earth would you not mandate that until the cause is identified the inspection be done before every flight ?
Is it time to put the calculators down and start doing, let's call it AMARPAMM (As Much As is Reasonably Practical And Money doesn't Matter) until cause/s of any incidents with potentially catastrophic consequences are conclusively dealt with ?
Now we have a MGB mounting lug that has had cracks appearing, first noticed at the beginning of this year, and as I understand it, the cause has not yet been determined.
The OEM has however stated "Analysis shows the aircraft can operate safely for a minimum of 10 hours, even assuming a full mount fracture and resulting worst-case stresses". I suppose one can probably assume this is where the "10 hours" came from in the current inspection interval.
Even if you have absolutely no doubt whatsoever that the manufacturer was able to replicate all possible known full mount fracture and resultant worst-case stress scenarios during their analysis and that 10 hours is the number, given the potential consequences if further damage were to occur after one mount had been fully fractured, why on earth would you not mandate that until the cause is identified the inspection be done before every flight ?
Is it time to put the calculators down and start doing, let's call it AMARPAMM (As Much As is Reasonably Practical And Money doesn't Matter) until cause/s of any incidents with potentially catastrophic consequences are conclusively dealt with ?
madrock
Inclined to agree with your sentiment. The stress calculations that prove that its safe to operate between checks for 10hrs are presumably done using the same methodology and perhaps by the same guy that did the initial stress calculations and worked out that the feet wouldn't crack within the TBO of the gearbox (2000 hrs or so?) plus a good chunk of safety margin. With the feet cracking at as little as 5 hrs time since new, what does that say for the integrity of the calculations?
But you might find that a prudent operator will be visually checking the feet on every shutdown at base anyway.
HC
Inclined to agree with your sentiment. The stress calculations that prove that its safe to operate between checks for 10hrs are presumably done using the same methodology and perhaps by the same guy that did the initial stress calculations and worked out that the feet wouldn't crack within the TBO of the gearbox (2000 hrs or so?) plus a good chunk of safety margin. With the feet cracking at as little as 5 hrs time since new, what does that say for the integrity of the calculations?
But you might find that a prudent operator will be visually checking the feet on every shutdown at base anyway.
HC
Horror Box:
I understand that. But with the issue of the mounting feet cracking we suddenly have turned away from the fact that the S-92 main transmission no longer meets FAR Part 29 certification standards. SAC was quite obviously WRONG about the cooler being the "only" source of an oil leak. Changing from titanium bolts to some new metal does not guarantee that the problem is solved with respect to a possible leak at the filter. If cracks can form in other places (mounting feet, etc.) is it totally impossible for a crack to occur in the transmission case itself?
So.
Do we just forget about it? Do we just say that the 30-minute "run dry" capability is of no real, practical use or value in the real world, so why require it at all?
FH1100pilot, just to try and clarify, as I think a fair bit of confusion is slipping in - to the best of my knowledge, the 10 hour inspection is on the mounting feet of the MGB, not the oil filter housing studs.
So.
Do we just forget about it? Do we just say that the 30-minute "run dry" capability is of no real, practical use or value in the real world, so why require it at all?
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From Sikorsky - "That language is fully compliant with the ... requirement to prove 30 minutes of flight after detection of an oil leak."
When the determination of engineering standards is established by interpretation of language, we're moving into the area of cost-saving and ass-covering as the primary tools of achieving those standards. Just think about how much it would have cost to re-design and re-work the MRG to meet the 30-minute standard if, as tested, it was only capable of lasting 10.
A man I know who worked for Bristow Helicopters, bemoaning changes to culture in the company, said to me some years ago that "in Old Man Bristow's day, this was a helicopter company that made a profit, whereas now, it's a profit-making company that uses helicopters. It might as well be lorries for all the difference it makes to the bean-counters!"
The culture of advancement and ass-covering in large corporations is pretty much the same as the culture of advancement and ass-covering in large public service bodies and the use of language is becoming more and more the same - that is to say, it is wilfully misleading while not exposing anybody to challenge. That quote from the Sikorsky man sounds just like something we'd expect to hear in Yes, Minister!
Which of the major car manufacturers allowed a defect to run without a recall because it calculated the likely cost of litigation would be less than the estimated cost of the recall?
And didn't one American airline introduce the concept of "negative profit" (i.e., a loss) way back?
Use of language - what a way to judge engineering standards, eh?
When the determination of engineering standards is established by interpretation of language, we're moving into the area of cost-saving and ass-covering as the primary tools of achieving those standards. Just think about how much it would have cost to re-design and re-work the MRG to meet the 30-minute standard if, as tested, it was only capable of lasting 10.
A man I know who worked for Bristow Helicopters, bemoaning changes to culture in the company, said to me some years ago that "in Old Man Bristow's day, this was a helicopter company that made a profit, whereas now, it's a profit-making company that uses helicopters. It might as well be lorries for all the difference it makes to the bean-counters!"
The culture of advancement and ass-covering in large corporations is pretty much the same as the culture of advancement and ass-covering in large public service bodies and the use of language is becoming more and more the same - that is to say, it is wilfully misleading while not exposing anybody to challenge. That quote from the Sikorsky man sounds just like something we'd expect to hear in Yes, Minister!
Which of the major car manufacturers allowed a defect to run without a recall because it calculated the likely cost of litigation would be less than the estimated cost of the recall?
And didn't one American airline introduce the concept of "negative profit" (i.e., a loss) way back?
Use of language - what a way to judge engineering standards, eh?
heliski22
That would have been Ford with their (in)famous Pinto.
Burn, baby, burn!
Which of the major car manufacturers allowed a defect to run without a recall because it calculated the likely cost of litigation would be less than the estimated cost of the recall?
Burn, baby, burn!