225 cleared to fly in UK & Norway
Originally Posted by Self loading bear
I see a good opportunity to test the effectivity of Airbus media campaign:
Have Airbus CEO Guillaume Faury picked up from his lawn by company H225 every morning for the daily ride into the office.
Let his wife wave him off.
Ask his wife how she feels:
- after 1 month
- after 3 months
- after a Year
SLB
Have Airbus CEO Guillaume Faury picked up from his lawn by company H225 every morning for the daily ride into the office.
Let his wife wave him off.
Ask his wife how she feels:
- after 1 month
- after 3 months
- after a Year
SLB
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Originally Posted by helicrazi
There is an energy voice survey now being done asking if you would fly in one again,
after you click your decision it tells you the current polling results and how many have voted
Surprisingly at the moment, its 86% would fly in it again and 10% no, seems a bit different from the airbus poll
after you click your decision it tells you the current polling results and how many have voted
Surprisingly at the moment, its 86% would fly in it again and 10% no, seems a bit different from the airbus poll
With so many oil workers and contractors losing their jobs and with little possibility of finding similar employment at the moment, maybe many of the people willing to fly in the 225 are simply agreeing to do so out of fear of losing their livelihood if they refused.
If people could walk out of a job and find another one shortly afterwards, the survey results may well be a lot different.
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Originally Posted by casper64
Interesting video on Airbus website:
lInfo Centre - Airbus Helicopters
lInfo Centre - Airbus Helicopters
All four good measures but they also cut TBO to a quarter and maintenance is limited to Airbus approved maintenance centers.
(Was this not always the case?)
This is only right if they would know and could prove that all these 3 or 4 cheese holes have lined up in this crash. (I.e. Dirt ingress has caused spalling on a previously shock loaded surface of a higher stressed bearing type)
But removal of the more vunerable bearing type is not the complete solution?
I am willing to give credits for the measures they have taken.
But I think they still not know precise.
The maintenance and inspections they have implemented will probably eliminate a sound business case for commercial use?
Perhaps somebody can give insight in what this means on Cost per seat Mile (not down to the penny but more or less relative to S92)
SLB
Originally Posted by Self loading bear
I have watched the video, indeed interesting. Outside the video they say that they know what happened but in the video they bet on 4 horses: different types bearings; better detection of smaller spalling particles; preventing or signalling shock loads when in transport and preventing dirt ingress while not mounted in aircraft.
All four good measures but they also cut TBO to a quarter and maintenance is limited to Airbus approved maintenance centers.
(Was this not always the case?)
This is only right if they would know and could prove that all these 3 or 4 cheese holes have lined up in this crash. (I.e. Dirt ingress has caused spalling on a previously shock loaded surface of a higher stressed bearing type)
But removal of the more vunerable bearing type is not the complete solution?
I am willing to give credits for the measures they have taken.
But I think they still not know precise.
The maintenance and inspections they have implemented will probably eliminate a sound business case for commercial use?
Perhaps somebody can give insight in what this means on Cost per seat Mile (not down to the penny but more or less relative to S92)
SLB
All four good measures but they also cut TBO to a quarter and maintenance is limited to Airbus approved maintenance centers.
(Was this not always the case?)
This is only right if they would know and could prove that all these 3 or 4 cheese holes have lined up in this crash. (I.e. Dirt ingress has caused spalling on a previously shock loaded surface of a higher stressed bearing type)
But removal of the more vunerable bearing type is not the complete solution?
I am willing to give credits for the measures they have taken.
But I think they still not know precise.
The maintenance and inspections they have implemented will probably eliminate a sound business case for commercial use?
Perhaps somebody can give insight in what this means on Cost per seat Mile (not down to the penny but more or less relative to S92)
SLB
Is that a mirror, almost hidden by all this smoke?
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Originally Posted by helicrazi
There is an energy voice survey now being done asking if you would fly in one again,
after you click your decision it tells you the current polling results and how many have voted
Surprisingly at the moment, its 86% would fly in it again and 10% no, seems a bit different from the airbus poll
for you maths gurus, there are 2 other options to make up the remaining percentage. cant remember what they were, one was something about being happy with the s92 as replacement.
after you click your decision it tells you the current polling results and how many have voted
Surprisingly at the moment, its 86% would fly in it again and 10% no, seems a bit different from the airbus poll
for you maths gurus, there are 2 other options to make up the remaining percentage. cant remember what they were, one was something about being happy with the s92 as replacement.
It doesn't take a maths guru to see that the voting trend is now more and more towards "No", currently 49% overall and that very few have been added to the "Yes" vote, currently 43% overall. In the last 24 hours the additional voting has been 71% "No" and 19% "Yes". Interestingly the Sikorsky popularity is climbing slowly so maybe the Airbus lobby had their say yesterday
It depends how you interpret the video...
THE cause of the crash was the minor spalling on the inside of the ring gear, this seems 100% certain. Now the question is: how did this spalling happen??? For this they made this huge fault tree analysis and came up with the following possible causes:
A: by intrusion of small particles
B: by shockload
C: by pressure of the roller bearings
D: by fatigue
E: a possible combination of the above.
To counter this they;
A: Reduced the risk of particles entering the gearbox by the additional covers and to perform the work only in certified maintenance centers.
B: To counter effect of shock loads they installed monitor sensors on transport cases, remove gearboxes with "incidents" from the fleet and have maintenance done in certified maintenance centers.
C: To counter the effect of the pressure of the rolling bearings they have removed the version with the generally higher pressure from the fleet, reduced lifetime of MGB.
D: To counter the effect of fatigue they have reduced lifetime on MGB, reduced stress with only allowing the better bearings.
E: To counter the risk of undetected spalling they raised inspection intervals and installed better chip detectors.
Now with all those measures in place I think they covered all most likely causes of the accident. Is it a 100% guarantee??? No, but we will never have a 100% certainty with mechanical things flying through the air... If you additionally add up the fact that these gearboxes also have 100 of thousands if not millions of hours of flighttime I think it is currently even safer than when putting in a brand new gearbox design as some have suggested. I would get on one without hesitation.
THE cause of the crash was the minor spalling on the inside of the ring gear, this seems 100% certain. Now the question is: how did this spalling happen??? For this they made this huge fault tree analysis and came up with the following possible causes:
A: by intrusion of small particles
B: by shockload
C: by pressure of the roller bearings
D: by fatigue
E: a possible combination of the above.
To counter this they;
A: Reduced the risk of particles entering the gearbox by the additional covers and to perform the work only in certified maintenance centers.
B: To counter effect of shock loads they installed monitor sensors on transport cases, remove gearboxes with "incidents" from the fleet and have maintenance done in certified maintenance centers.
C: To counter the effect of the pressure of the rolling bearings they have removed the version with the generally higher pressure from the fleet, reduced lifetime of MGB.
D: To counter the effect of fatigue they have reduced lifetime on MGB, reduced stress with only allowing the better bearings.
E: To counter the risk of undetected spalling they raised inspection intervals and installed better chip detectors.
Now with all those measures in place I think they covered all most likely causes of the accident. Is it a 100% guarantee??? No, but we will never have a 100% certainty with mechanical things flying through the air... If you additionally add up the fact that these gearboxes also have 100 of thousands if not millions of hours of flighttime I think it is currently even safer than when putting in a brand new gearbox design as some have suggested. I would get on one without hesitation.
As Twist and Shout points out, we have two very similar accidents and the bearings are the only obvious common element.
The discussion in this thread suggests that the internal component failure process may not produce significant particles before complete disintegration.
Passengers would be more confident in the fixes if the huge effort AH has put into analyzing these accidents had allowed them to reproduce the MGB failures that occurred. Without that, concern remains that the fixes are not addressing the problem.
The discussion in this thread suggests that the internal component failure process may not produce significant particles before complete disintegration.
Passengers would be more confident in the fixes if the huge effort AH has put into analyzing these accidents had allowed them to reproduce the MGB failures that occurred. Without that, concern remains that the fixes are not addressing the problem.
Originally Posted by etudiant
As Twist and Shout points out, we have two very similar accidents and the bearings are the only obvious common element.
The discussion in this thread suggests that the internal component failure process may not produce significant particles before complete disintegration.
Passengers would be more confident in the fixes if the huge effort AH has put into analyzing these accidents had allowed them to reproduce the MGB failures that occurred. Without that, concern remains that the fixes are not addressing the problem.
The discussion in this thread suggests that the internal component failure process may not produce significant particles before complete disintegration.
Passengers would be more confident in the fixes if the huge effort AH has put into analyzing these accidents had allowed them to reproduce the MGB failures that occurred. Without that, concern remains that the fixes are not addressing the problem.
Originally Posted by etudiant
Passengers would be more confident in the fixes if the huge effort AH has put into analyzing these accidents had allowed them to reproduce the MGB failures that occurred.
Originally Posted by henra
In a way, yes. On the other hand the fact that they couldn't reproduce it straight forward shows that it must be a very unlikely combination of factors. Now they eliminated or reduced multiple additional factors besides the obvious one (the Bearing manufacturer - seeing the different rollers in the video gave me shivers - how can so differently radiused rollers be equally suited to the same application?). Personally I would say with all these measures in place the next helicopter to lose an entire MGB will be a different Make/Model. Will it be economically viable? Well that is a good question.
Originally Posted by henra
Now they eliminated or reduced multiple additional factors besides the obvious one (the Bearing manufacturer - seeing the different rollers in the video gave me shivers - how can so differently radiused rollers be equally suited to the same application?).
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One point to note is that as well as removing any gearbox which has suffered impact from service, they also removed any having had a lightning strike.
The gearbox fitted in the L2 accident had sustained a lightning strike while fitted to a different airframe. Maybe they cannot categorically say it is the gear types because both gearboxes had encountered external factors which could contribute to the cause.
The gearbox fitted in the L2 accident had sustained a lightning strike while fitted to a different airframe. Maybe they cannot categorically say it is the gear types because both gearboxes had encountered external factors which could contribute to the cause.
Originally Posted by SASless
Bottom line....one more fatal occurrence and the Fat Lady will have sung.
Human nature (for most of us) means we tend to believe things we are told.
Otherwise everything breaks down.
The problem with people/companies that lie, is you can no longer believe anything they say.
Maybe AH had several transmissions fail during their attempts to replicate the catostrophic failure, and are simply lying about that too.
I have no knowledge to suggest this, just pointing out that once someone looks you in the eye and lies to you, it is foolish to ever believe anything they say again.
I won’t.
Otherwise everything breaks down.
The problem with people/companies that lie, is you can no longer believe anything they say.
Maybe AH had several transmissions fail during their attempts to replicate the catostrophic failure, and are simply lying about that too.
I have no knowledge to suggest this, just pointing out that once someone looks you in the eye and lies to you, it is foolish to ever believe anything they say again.
I won’t.
Originally Posted by Noiseboy
One point to note is that as well as removing any gearbox which has suffered impact from service, they also removed any having had a lightning strike.
The gearbox fitted in the L2 accident had sustained a lightning strike while fitted to a different airframe. Maybe they cannot categorically say it is the gear types because both gearboxes had encountered external factors which could contribute to the cause.
The gearbox fitted in the L2 accident had sustained a lightning strike while fitted to a different airframe. Maybe they cannot categorically say it is the gear types because both gearboxes had encountered external factors which could contribute to the cause.
It probably takes an external damage event (e.g. like lightning strike or transport damage) to trigger premature spalling and propagation of cracks. The design itself seems to be OK as long as no such premature initiation occurs (otherwise more H225/AS332 helicopters would have lost their gearboxes - they accumulated massive fleet hours without such occurrences). It appears that it is simply not very tolerant against such external influences. And the combination of that particular bearing type producing higher peak stresses in the outer race plus an external factor was apparently sufficient in two instances to trigger this premature cracking. The really unfortunate part is that this damage mechanism isn't really properly captured by HUMS&Co. That is what makes it so dangerous.
Originally Posted by SASless
Bottom line....one more fatal occurrence and the Fat Lady will have sung.
That said with the current level of precautionary measures and low flying hours you will probably have to wait rather long for this.
Originally Posted by henra
One more fatal accident caused by mechanical problems (not only Gearbox related) would indeed be the final nail in the coffin at least for civil ops.
That said with the current level of precautionary measures and low flying hours you will probably have to wait rather long for this.
That said with the current level of precautionary measures and low flying hours you will probably have to wait rather long for this.
A question that does arise.....why no such failures in military aircraft.....or have there been some?
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Originally Posted by casper64
I don't know if the other crashed aircraft had the same bearings, but in case it had, then this is taken care of by removing these bearings from service, as the other ones never had an issue. Additional safety on the MGBs that never had an issue in the first place, is then subsequently provided by increasing inspections, reducing lifetime and better chip detectors. This should take care of the problem... again, 100% guarantee? No. But if you want 100% one should just stay where humans belong: with 2 feet on the ground...
Originally Posted by SASless
A question that does arise.....why no such failures in military aircraft.....or have there been some?
At least I'm not aware of any such occurrence in military use.
Would surely have come up by now.
So why not in the military?
- Luck?
- less intense utilisation?
- More frequent/intense inspections?
- No unfortunate combination of external event (Lightning strike, transport damage) with that same type of bearing?
- any combination thereof?
- other?
Good question.
Last edited by henra; 8th Oct 2017 at 17:02.
