North Sea heli ditching: Oct 2012
You are right Jim the AD 2012-0115E that was in effect at the time would have excluded G-CHCN.
However what data or analysis was done to to allow the formation of that directive?
If there is a sound body of engineering work then that would be fair enough but if it exists then it isn't in the public domain. Even if it was discussed between the operators it seems extremely odd that 2 (of 3 or the majority) have decided to monitor more closely than the AD. Which suggests the formation of 2012-115E is flakey.
If the logic was flawed then how and what is or should be taken as correct for the future?
However what data or analysis was done to to allow the formation of that directive?
If there is a sound body of engineering work then that would be fair enough but if it exists then it isn't in the public domain. Even if it was discussed between the operators it seems extremely odd that 2 (of 3 or the majority) have decided to monitor more closely than the AD. Which suggests the formation of 2012-115E is flakey.
If the logic was flawed then how and what is or should be taken as correct for the future?
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When I was flying the Super Puma in the 80's we didnt have the HUMS gizmo
We relied purely chip detectors.
If the gearbox was suspect it was probably replaced, this happened on a regular basis, on average...pulling a gearbox once a month!
Now this gizmo lets gearboxes go for a much longer time, this is a bit scary because I dont think it is that good at detecting a major fault.
Its not that intelligent, trend analysis or what?
OK for jet engines but not ok for helicopter gearboxes
There seems to me to be a major design flaw.
History will prove this fact.
I know this is not comforting info but I just want to view my feelings about this particular helicopter from my own experience of flying it.
I want to fly with confidence, I never felt confident with this particular helicopter.
Who remembers the first Super Puma to be written off at ABZ G-TIGD yes a flaw that was known in the Puma but forgotten in the Super Puma
Hums is a weak secondary back up, what is needed is a sound design that everyone feels safe with.
We relied purely chip detectors.
If the gearbox was suspect it was probably replaced, this happened on a regular basis, on average...pulling a gearbox once a month!
Now this gizmo lets gearboxes go for a much longer time, this is a bit scary because I dont think it is that good at detecting a major fault.
Its not that intelligent, trend analysis or what?
OK for jet engines but not ok for helicopter gearboxes
There seems to me to be a major design flaw.
History will prove this fact.
I know this is not comforting info but I just want to view my feelings about this particular helicopter from my own experience of flying it.
I want to fly with confidence, I never felt confident with this particular helicopter.
Who remembers the first Super Puma to be written off at ABZ G-TIGD yes a flaw that was known in the Puma but forgotten in the Super Puma
Hums is a weak secondary back up, what is needed is a sound design that everyone feels safe with.
HUMS is a nice tool if you know how to use it.
I don't think all operators train their staff as well as they could do...
In a ideal world items would be strong enough to last but that probably means items will be more expensive and since the safety culture is also based on a risk to money ratio this will never happen
.
RP
I don't think all operators train their staff as well as they could do...
In a ideal world items would be strong enough to last but that probably means items will be more expensive and since the safety culture is also based on a risk to money ratio this will never happen
.RP
M O E
TIGD was of course a tail rotor drive fairing that came open and hit the tail rotor on short finals, there were some injuries but none fatal.
Sorry but you haven't got it right. Chip detection is still just as important as it was in the 80s. Chip detectors are useful for defects when debris is released - eg bearing surfaces degrading etc. But what it was no good at was detecting a crack where no debris was released.
That is the point of HUMS, it can in some cases detect a non-debris-releasing fault before catastrophy. There is certainly no suggestion of continuing to operate a gearbox that is generating debris on the chip detector, just because HUMS says it is OK.
The two techniques are complementary.
There were a lot of debris-releasing faults in the early days of the 332L back in the early 80s, but these were fixed by changes in operational procedure, design and materials, not by the addition of HUMS.
If you are not happy flying this type of helicopter, nobody is forcing you to do it and I suggest you get a different job, or one flying a helicopter that cannot possibly suffer any mechanical problem. Good luck with that!
In truth I'm afraid I read your post as an uninformed gripe against the Super Puma family, trying to "stir it" based on incorrect speculation. You are of course entitled to publicy air your opinion even if incorrect, but it would be better for the industry and the passengers if you desisted.
TIGD was of course a tail rotor drive fairing that came open and hit the tail rotor on short finals, there were some injuries but none fatal.
Sorry but you haven't got it right. Chip detection is still just as important as it was in the 80s. Chip detectors are useful for defects when debris is released - eg bearing surfaces degrading etc. But what it was no good at was detecting a crack where no debris was released.
That is the point of HUMS, it can in some cases detect a non-debris-releasing fault before catastrophy. There is certainly no suggestion of continuing to operate a gearbox that is generating debris on the chip detector, just because HUMS says it is OK.
The two techniques are complementary.
There were a lot of debris-releasing faults in the early days of the 332L back in the early 80s, but these were fixed by changes in operational procedure, design and materials, not by the addition of HUMS.
If you are not happy flying this type of helicopter, nobody is forcing you to do it and I suggest you get a different job, or one flying a helicopter that cannot possibly suffer any mechanical problem. Good luck with that!
In truth I'm afraid I read your post as an uninformed gripe against the Super Puma family, trying to "stir it" based on incorrect speculation. You are of course entitled to publicy air your opinion even if incorrect, but it would be better for the industry and the passengers if you desisted.
With respect HC I don't think that is fair.
Just look at the situation that exists around the EC225 right now.
You have EASA airworthiness directives (as recently as August 2012) relating to issues from the accident of G-REDU in Feb 2009.
You have what seems a total mess with the latest issues from REDW and CHCN where you find 3 operators, 2 aviation authorities, a manufacturer, an accident investigation branch and a helicopter safety working group unable to co-ordinate properly which leads to a situation where the CAA and EASA have differing airworthness for the same type.
I mean WTF!?!
Just look at the situation that exists around the EC225 right now.
You have EASA airworthiness directives (as recently as August 2012) relating to issues from the accident of G-REDU in Feb 2009.
You have what seems a total mess with the latest issues from REDW and CHCN where you find 3 operators, 2 aviation authorities, a manufacturer, an accident investigation branch and a helicopter safety working group unable to co-ordinate properly which leads to a situation where the CAA and EASA have differing airworthness for the same type.
I mean WTF!?!
I want to fly with confidence, I never felt confident with this particular helicopter.
The RAF bolted down the inclined shaft hinge pin in 1972. When I joined Bristow I suggested that they do the same thing to their 330Js. I wasn't listeded to because I was a crab but luckily one migrated about six inches out about a week later so they did it. Super Puma comes along, same system. Doogal (RIP) and myself protested. 'This isn't a Puma. this is a Super Puma'. The rest is history.
Neither of the two aircarft that ditched this year ditched because of the geabox mechanical fault. They ditched because the EMLUB warning system failed, otherwise they would have proceeded with their 30 mins clearance and made landfall.
made landfall???
really... and on what hard evidence are you going to back that statement? i would love to see where the evidence is that this shaft would have lasted 30 mins having already fractured!!!!
really... and on what hard evidence are you going to back that statement? i would love to see where the evidence is that this shaft would have lasted 30 mins having already fractured!!!!
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Neither of the two aircarft that ditched this year ditched because of the geabox mechanical fault. They ditched because the EMLUB warning system failed, otherwise they would have proceeded with their 30 mins clearance and made landfall.
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In my small opinion...........those heli has a big insurance at the back......and when the FM say land immediately I will do immediatelyI don't care if is thrue or false and I don't care to wait for see what happen
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many thanks for your replies to my posts gents. It was not my intention to slate any one of the operators maintenance procedures or finger point. I have absolutely no doubt that they are all of an exceptional standard. After the tragic incident with the bond machine, we were given a tour around their facility and shown how they go about maintenance procedures etc. I was astounded at the attention to detail that goes into aircraft maintenance. It was very reassuring to see this. If only we carried out maintenance like that offshore!
I also take great comfort in the fact that the guys who fly these machines would not be doing so if they believed for one moment that they were unsafe. a point was made about gossip and rumours offshore regarding helicopters, that point couldn't be closer to the truth. the amount of rumours etc and some of the attitudes of members of offshore staff only enhances these rumours.
It would be usefull for us if the operators sent some information as to what was happening as it is found out. although I am sure there are probably legal implications in doing so.
I also take great comfort in the fact that the guys who fly these machines would not be doing so if they believed for one moment that they were unsafe. a point was made about gossip and rumours offshore regarding helicopters, that point couldn't be closer to the truth. the amount of rumours etc and some of the attitudes of members of offshore staff only enhances these rumours.
It would be usefull for us if the operators sent some information as to what was happening as it is found out. although I am sure there are probably legal implications in doing so.
Last edited by abzoilworker; 16th Nov 2012 at 19:46.
Helicrazi.......Made landfall!!!
Absolutely no doubt that the emlube was working in both May and October ditchings and if it hadn't given the pilots a false warning of having failed, they would have been able to continue flight at 80 knots for 30 minutes. Land was within reach in both events, I believe.
How many times does it need to be repeated that the fractured shaft which drives both oil pumps has nothing at all to do with the emlube system which is situated outside the gearbox and has no shaft driving it, ever ? !!!
I have been flying EC225s for over 3000 hours and I'd appreciate that before anyone makes "knee-jerk" comments about this superb helicopter, they should first check their facts.
Absolutely no doubt that the emlube was working in both May and October ditchings and if it hadn't given the pilots a false warning of having failed, they would have been able to continue flight at 80 knots for 30 minutes. Land was within reach in both events, I believe.
How many times does it need to be repeated that the fractured shaft which drives both oil pumps has nothing at all to do with the emlube system which is situated outside the gearbox and has no shaft driving it, ever ? !!!
I have been flying EC225s for over 3000 hours and I'd appreciate that before anyone makes "knee-jerk" comments about this superb helicopter, they should first check their facts.
Neither of the two aircarft that ditched this year ditched because of the geabox mechanical fault. They ditched because the EMLUB warning system failed, otherwise they would have proceeded with their 30 mins clearance and made landfall.
Since I am not all that familiar with this aircraft, I ask for understanding:
Am I correct in understanding that the emergency lubrication didn't begin to provide lube (i.e. provide lube to the gearbox when the normal lube failed due to the shaft no longer driving the pumps)
or
that the emergency system (as described by Colibri above) was actually providing the back up lube, but the warning sytem told the pilots a different story.
No, you aren't getting any more lube, emergency or otherwise
hence no choice but to ditch?
My understanding is that "no lube was happening from the emergency lube" but I may be confusing myself or not reading your remarks properly.
Last edited by Lonewolf_50; 16th Nov 2012 at 19:40.
i dont see how you can conclude that after that fracture the gearbox would withstand another 30 mins, regardless of your 80kts speed, EASA stated it may not be torque related, so flying at 80 kts and low torque seems irrelevant?
i do not doubt that emlube system was working, infract i believe it was working effectively, its the fracture that worries me about the whole integrity
i do not doubt that emlube system was working, infract i believe it was working effectively, its the fracture that worries me about the whole integrity
Last edited by helicrazi; 16th Nov 2012 at 19:44.
The indication that the EMLUB system failed was probably their saving grace. Who knows what the outcome would have been if they had continued flight for 30 minutes with the broken part of the shaft thrashing around.
No ! You take note. The bevel shaft which drives the two oil pumps is right at the bottom of the main gearbox and it is welded to the bottom of the main shaft.
When it fractured each time at the 360 degree weld, the shaft simply dropped into the sump, so that the bevel gear was no longer engaged with the two pumps.
No other components of the gearbox were, or could have been mechanically affected, except by lack of lubrication. Everything else in the gearbox just carried on working normally and all that was needed was glycol from the external emlube system to keep critical components cool.
This glycol was found in both affected gearboxes after stripping down and no damage was found on any other components. They are isolated from any possible contact with the fractured bevel gear shaft.
When it fractured each time at the 360 degree weld, the shaft simply dropped into the sump, so that the bevel gear was no longer engaged with the two pumps.
No other components of the gearbox were, or could have been mechanically affected, except by lack of lubrication. Everything else in the gearbox just carried on working normally and all that was needed was glycol from the external emlube system to keep critical components cool.
This glycol was found in both affected gearboxes after stripping down and no damage was found on any other components. They are isolated from any possible contact with the fractured bevel gear shaft.
Ok, you direct me to any publication that states that no other damage was found and i may stand corrected?
otherwise, how do you know that the shaft wasnt tested in its true weight before it was sheared and after it has sheared it is not going to throw all the balances out? personally, i would be ditching as i dont think 'landfall' would ever arrive...
otherwise, how do you know that the shaft wasnt tested in its true weight before it was sheared and after it has sheared it is not going to throw all the balances out? personally, i would be ditching as i dont think 'landfall' would ever arrive...
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Originally Posted by Lonewolf_50
Am I correct in understanding that the emergency lubrication didn't begin to provide lube (i.e. provide lube to the gearbox when the normal lube failed due to the shaft no longer driving the pumps)
or
that the emergency system (as described by Colibri above) was actually providing the back up lube, but the warning sytem told the pilots a different story.
or
that the emergency system (as described by Colibri above) was actually providing the back up lube, but the warning sytem told the pilots a different story.
That is the cause for the ditching, it is an entirely different discussion of whether if the Emlube didn't give a false indication whether the gearbox would have carried on regardless.
Si
Last edited by bigglesbutler; 16th Nov 2012 at 21:06.