EC 225 Return to REAL Service
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If we look at the history of S-61 accidents then the ones in the back may not be the biggest issue. Two other things are going on.
The 234 stood out because it carried a lot of passengers and put a larger number of people at risk in a single event.
The Super Puma stands out because it has been the dominant offshore passenger carrying tool in the internet age when the outrageous views of the ignorant carry more weight than informed alternatives.
The 234 stood out because it carried a lot of passengers and put a larger number of people at risk in a single event.
The Super Puma stands out because it has been the dominant offshore passenger carrying tool in the internet age when the outrageous views of the ignorant carry more weight than informed alternatives.
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If we look at the history of S-61 accidents then the ones in the back may not be the biggest issue. Two other things are going on.
The 234 stood out because it carried a lot of passengers and put a larger number of people at risk in a single event.
The Super Puma stands out because it has been the dominant offshore passenger carrying tool in the internet age when the outrageous views of the ignorant carry more weight than informed alternatives.
The 234 stood out because it carried a lot of passengers and put a larger number of people at risk in a single event.
The Super Puma stands out because it has been the dominant offshore passenger carrying tool in the internet age when the outrageous views of the ignorant carry more weight than informed alternatives.
The S-61 did have a number of accidents in the pioneering days of the North Sea but the ones you listed previously were of various different root causes and most of those would be readily preventable with today’s inspection technology. Planetary gears are still only accessible during overhaul. I know you have collated a lot of data, so can you pick out 2 components of the S-61 that failed in very similar manners (at least one component causing loss of life twice) and each time the manufacturer claimed to have the problem solved after the first occurrence?
The issue the workforce and clients have is not so much with the Super Puma per se although that is how it may be labelled; it is with Airbus Helicopters. There is a loss of confidence in the manufacturer, due almost as much to their statements as to the failure of their components. The uncertainty in many peoples' minds is “how well has the rest of the thing been engineered?”.
My particular outrageous view is that the upgrading of the Super Puma gearbox to take the increased power of the L2 and EC225 was poorly engineered. In complex stress analyses, particular stress components appear to have been ignored in both the bevel gear shaft and the 2nd stage planet gear/bearings. I base that view upon the findings of the AAIB into failures of those components in REDL, REDW and CHCN. Safety margins were compromised so it would only be a matter of time before manufacturing quality and assembly tolerances lined up the other holes.
Yes Pablo, but more specific, the sun mesh drives one flank and the ring drives on the other side, whereas in a single mesh you only have loading typically on one side of a tooth. On top of that, as a tooth is loaded it causes the root behind it to load in tension. When the next tooth is loaded the same root location is reversed into compression. When this same root is exposed to mesh on the ring gear, the opposite occurs. The first stress is compression, then tension. Some argue that this t-c-c-t is really a unique application of the goodman correction, and could be treated like a single cycle. Further complicating is that the exact root location of peak stress for each mesh may not and probably is not, the same, nor is the t and c magnitude the same, depending on deflection and other factors....
.. but this digresses. The fatigue in this case is starting at the bearing race ID, so more like a rolling wheel fatigue than gear tooth problem I would venture to guess.
AH may not really understand this, since they don't design the transmission we are told. Likewise, the transmission design team may not understand actual flight loads, since they are not the air vehicle experts. I have said before, parts only break when load exceeds strength. Which path to go here? My guess is load is not fully understood, but there may be a strength differential between suppliers.
.. but this digresses. The fatigue in this case is starting at the bearing race ID, so more like a rolling wheel fatigue than gear tooth problem I would venture to guess.
AH may not really understand this, since they don't design the transmission we are told. Likewise, the transmission design team may not understand actual flight loads, since they are not the air vehicle experts. I have said before, parts only break when load exceeds strength. Which path to go here? My guess is load is not fully understood, but there may be a strength differential between suppliers.
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Yes Pablo, but more specific, the sun mesh drives one flank and the ring drives on the other side, whereas in a single mesh you only have loading typically on one side of a tooth. On top of that, as a tooth is loaded it causes the root behind it to load in tension. When the next tooth is loaded the same root location is reversed into compression. When this same root is exposed to mesh on the ring gear, the opposite occurs. The first stress is compression, then tension. Some argue that this t-c-c-t is really a unique application of the goodman correction, and could be treated like a single cycle. Further complicating is that the exact root location of peak stress for each mesh may not and probably is not, the same, nor is the t and c magnitude the same, depending on deflection and other factors....
.. but this digresses. The fatigue in this case is starting at the bearing race ID, so more like a rolling wheel fatigue than gear tooth problem I would venture to guess.
.. but this digresses. The fatigue in this case is starting at the bearing race ID, so more like a rolling wheel fatigue than gear tooth problem I would venture to guess.
That's a good explanation. Basically, a simple epicyclic planet gear is similar to an idler gear. With regards to tooth root tensile fatigue stress due to bending, AGMA recommends a material knock down factor of 0.70 for teeth subject to the type of alternating reverse load cycles experienced by planet or idler gears.
Another thing to consider is that aircraft gears normally have the tooth root fillet surfaces carefully shot peened. This creates a compressive pre-stress in the surface. Since fractures in the surface initiate/propagate from excessive tensile stress, any residual compressive stress in the surface must be relieved before the surface is stressed in tension. Shot peening, when properly applied, can be very effective at improving tooth bending fatigue performance.
Interesting comments about the adequacy or otherwise of the design and engineering etc.
The cause of the damage to the gear and why it failed seems to be possibly strongly
connected to the fact that the gearbox fell off a truck in Australia.
That seems to be the angle the AIBN in Norway is taking from their last report.
As has been previously stated the other issue would be that damage of any kind
cannot be adequately determined in advance in service due to various failings
under the existing criteria.
Whichever way you look at it it is a huge clusterfu@k that will take a lot to rectify.
It will be interesting to see if the type survives of course in its intended role.
The cause of the damage to the gear and why it failed seems to be possibly strongly
connected to the fact that the gearbox fell off a truck in Australia.
That seems to be the angle the AIBN in Norway is taking from their last report.
As has been previously stated the other issue would be that damage of any kind
cannot be adequately determined in advance in service due to various failings
under the existing criteria.
Whichever way you look at it it is a huge clusterfu@k that will take a lot to rectify.
It will be interesting to see if the type survives of course in its intended role.
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I think calling the passengers "jibbering ballast" and " outrageous views of the ignorant" is really going too far. If you don't agree with a point, that's fine but don't start insulting those you disagree with.
I think the real problem with the Puma family is that it was hated before any of these accidents. The level of discomfort in the back is unreal, especially when this has to be endured for 2 to 3 hours. Only those that have endured this can understand the problems of getting up and trying to walk, especially if you are in the facing double seats on the starboard side. This could greatly impact your ability to get out quickly if you had too.
All those that keep saying what a fine helicopter this is - travel for a few hours in one and then lets hear your views. Throw in the fatal flaws and the aircraft is finished.
I think the real problem with the Puma family is that it was hated before any of these accidents. The level of discomfort in the back is unreal, especially when this has to be endured for 2 to 3 hours. Only those that have endured this can understand the problems of getting up and trying to walk, especially if you are in the facing double seats on the starboard side. This could greatly impact your ability to get out quickly if you had too.
All those that keep saying what a fine helicopter this is - travel for a few hours in one and then lets hear your views. Throw in the fatal flaws and the aircraft is finished.
Not at all. Columbia have lost a 234 in South America in the last year or two. I'm sure there have been other incidents too.
With no jibbering ballast in the back, logging accidents don't hit the headlines in the same way as offshore accidents.
With no jibbering ballast in the back, logging accidents don't hit the headlines in the same way as offshore accidents.
Yes, a 234 crashed and killed all of the occupants....as can happen to every type of aircraft. So...one fatal crash out in all the years since the North Sea event and that somehow suggests a problem in the design to you?
Let's compare the 234/CH-47 in Civilian Usage compared to the L2/225 shall we.
The 225 is getting bad Press AFTER two Crashes....unlike the 234 which got its bad Press BEFORE the crash. If you are old enough and still young enough to remember those days....a certain Operator very much did not want the 234 on the North Sea and worked towards that end.
a certain Operator very much did not want the 234 on the North Sea and worked towards that end
Last edited by Fareastdriver; 22nd Dec 2016 at 14:44.
I think calling the passengers "jibbering ballast" and " outrageous views of the ignorant" is really going too far. If you don't agree with a point, that's fine but don't start insulting those you disagree with.
I think the real problem with the Puma family is that it was hated before any of these accidents. The level of discomfort in the back is unreal, especially when this has to be endured for 2 to 3 hours. Only those that have endured this can understand the problems of getting up and trying to walk, especially if you are in the facing double seats on the starboard side. This could greatly impact your ability to get out quickly if you had too.
All those that keep saying what a fine helicopter this is - travel for a few hours in one and then lets hear your views. Throw in the fatal flaws and the aircraft is finished.
I think the real problem with the Puma family is that it was hated before any of these accidents. The level of discomfort in the back is unreal, especially when this has to be endured for 2 to 3 hours. Only those that have endured this can understand the problems of getting up and trying to walk, especially if you are in the facing double seats on the starboard side. This could greatly impact your ability to get out quickly if you had too.
All those that keep saying what a fine helicopter this is - travel for a few hours in one and then lets hear your views. Throw in the fatal flaws and the aircraft is finished.
The US Army Chinook above was particularly sad as it was carrying civvie parachute teams (including one from Swansea). It was also an early example how Health and Safety Inspectors can stop a process so as to protect factory workers - they reduced the pressure on air hoses which were used to clean transmission parts before reassembly; The lower pressure failed to remove some small particles which went on to block the lubrication nozzles and 46 people died.
I think the real problem with the Puma family is that it was hated before any of these accidents
I was too close to dying off so I was not considered for the 225 and in retrospect, being a professional pilot and having read Helicomparator's enthusing about the Flight Management System I am glad I wasn't.
My personal opinion which I have stated before was that the Puma family was stretched too far. A helicopter that entered service at 6,000kgs and expanded to 11,000kgs whilst keeping the aerodynamics at a similar size was a bridge too far, no matter how much more power or blades you added on.
The Chinook is a splendid helicopter. It ticks all the boxes as far as efficiency, speed and ease of handling. As a passenger aircraft it suffers from the problem of getting two rotor systems to stop arguing with each other. Floating floors, you name it, it doesn't work. I was told that on the inaugural trip to the Brent the cabin attendant planned to provide tea and biscuits en route. The tea was served but when they opened the locker to get the biscuits there was just a carpet of writhing crumbs.
Mass transit of Civilian passengers in helicopters didn't happen until they started drilling for oil offshore, up to then it was always military. The present litigation atmosphere did not exist so if a helicopter speared in with a load of grunts on board it was just one of those things. The transition to airline standards of safety have been hampered by the paucity of offshore operators and the accountants in the oil industry so it has lagged behind what could be regarded as satisfactory.
There is no demand for point to point travel with the general public so all the dreams of vertical take off airliners that have been put up in the past have come to nothing. It will continue to be so in the helicopter industry so we are lumbered with what we have now. There will not be any magical transition to a new era in the foreseeable future.
You are just going to have to clatter away hoping that that the designers and producers have got there figures right and whatever is holding you up stays in one piece.
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I've already owned up to being one of those "jabbering ballast" in the back.
To Fareastdriver - you have obviously never sat in the back for 3 hours plus. The 332 family are at best an unpleasant passenger experience.
I still recall my first ride in the 'new' 225 - marginally better seats but the same crush, where was the new aircraft?
I also remember riding in the 234. Frankly the only people you could force into the damn thing would be squaddies. Noisy, vibration levels which could shake you out of the seat and a seat pitch which makes the 332 seem spacious. Only oil companies thought them a good idea as they represented potential cost savings.
Obviously this is a pilot's forum, but I never cease to be surprised by helicopter pilots not understanding that they only have jobs to get, offshore at least, passengers safely from one place to another. All the pilot aids and wonderful other stuff counts for nothing. Then remember that if the passengers were actually paying for the flights and choosing the carrier / aircraft a lot of these aircraft would be lying in the back of a hangar.
The S-92 is the best of a poor lot. Still got high vibration levels and noise and the windows are far too small. But is just about does it. 139 just big enough and almost pleasant. 76? great with half load not nice otherwise. 200 series Bells? squaddy material again.
Worth remembering that the jibbering masses are the reason offshore types have jobs. Comparing the early days of offshore exploration with today's timetabled, mass transport very much ignores most of the progress of the last 30 odd years. On a modern platform just getting to and from it represents half the risk an offshore worker faces. They feel they have some control over their half, they have none over the helicopter portion. So then the new, "better, safer" types come in, and set the safety improvements a long way back........
To Fareastdriver - you have obviously never sat in the back for 3 hours plus. The 332 family are at best an unpleasant passenger experience.
I still recall my first ride in the 'new' 225 - marginally better seats but the same crush, where was the new aircraft?
I also remember riding in the 234. Frankly the only people you could force into the damn thing would be squaddies. Noisy, vibration levels which could shake you out of the seat and a seat pitch which makes the 332 seem spacious. Only oil companies thought them a good idea as they represented potential cost savings.
Obviously this is a pilot's forum, but I never cease to be surprised by helicopter pilots not understanding that they only have jobs to get, offshore at least, passengers safely from one place to another. All the pilot aids and wonderful other stuff counts for nothing. Then remember that if the passengers were actually paying for the flights and choosing the carrier / aircraft a lot of these aircraft would be lying in the back of a hangar.
The S-92 is the best of a poor lot. Still got high vibration levels and noise and the windows are far too small. But is just about does it. 139 just big enough and almost pleasant. 76? great with half load not nice otherwise. 200 series Bells? squaddy material again.
Worth remembering that the jibbering masses are the reason offshore types have jobs. Comparing the early days of offshore exploration with today's timetabled, mass transport very much ignores most of the progress of the last 30 odd years. On a modern platform just getting to and from it represents half the risk an offshore worker faces. They feel they have some control over their half, they have none over the helicopter portion. So then the new, "better, safer" types come in, and set the safety improvements a long way back........
is not going too far when you consider the social media campaigns and the misinformation in the press across the last few years. People who had never been near a helicopter were posting total rubbish on Facebook and then journalists were believing them. Then there was the sizeable group of people who have worked with helicopters for decades without bothering to learn anything about them.
Is it you that's been trying to steal my seat? Second row, starboard side, where I can see the instruments (and take control of the door release).
I have enjoyed my flying in Super Pumas. I felt a little less safe in some of the older ones with the smaller windows and dodgy liferaft stowage but since that won't be happening again I can happily feel some sense of history having flown in some of the original Tigers.
I am happy with the Super Puma 225. Here is why.
- It is a helicopter. "If it was meant to fly it would have wings." This is never going to be like getting in a A320.
- With hundreds of thousands of flight hours, much of it in a very demanding environment, across more than a decade, the 225 has had only one fatal accident that was not related to warlike operations. One fatal accident is one too many but nevertheless this is the best there is.
- Plenty large escape windows.
- Gearbox run-dry certification that people can believe.
- SS6 float certification.
- Smoooooooth.
I am aware that there are many thousands of people out there both in the offshore community and the SAR community who currently do not understand that there are helicopters that you cannot stand up in. Unfortunately, the Super Puma cabin height of 1.4m is normal for helicopters. A tall helicopter is not a good plan.
(By the way gasax, when I was last in a Chinook a few months ago, the guys thought I was nuts to describe it as quiet. None of them had ever been in a S-92.)
... I think the real problem with the Puma family is that it was hated before any of these accidents. The level of discomfort in the back is unreal, especially when this has to be endured for 2 to 3 hours. Only those that have endured this can understand the problems of getting up and trying to walk, especially if you are in the facing double seats on the starboard side. ...
I have enjoyed my flying in Super Pumas. I felt a little less safe in some of the older ones with the smaller windows and dodgy liferaft stowage but since that won't be happening again I can happily feel some sense of history having flown in some of the original Tigers.
I am happy with the Super Puma 225. Here is why.
- It is a helicopter. "If it was meant to fly it would have wings." This is never going to be like getting in a A320.
- With hundreds of thousands of flight hours, much of it in a very demanding environment, across more than a decade, the 225 has had only one fatal accident that was not related to warlike operations. One fatal accident is one too many but nevertheless this is the best there is.
- Plenty large escape windows.
- Gearbox run-dry certification that people can believe.
- SS6 float certification.
- Smoooooooth.
I am aware that there are many thousands of people out there both in the offshore community and the SAR community who currently do not understand that there are helicopters that you cannot stand up in. Unfortunately, the Super Puma cabin height of 1.4m is normal for helicopters. A tall helicopter is not a good plan.
(By the way gasax, when I was last in a Chinook a few months ago, the guys thought I was nuts to describe it as quiet. None of them had ever been in a S-92.)
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Jim - are you serious?
Quoting a partial accident record utterly undermines your creditability. Quote the full record or nothing at all. It is the easiest thing in the world to select a 'golden period' and then make an argument from it. Now try the 4 accidents and tell someone that the 10 year mean it is a really. really, safe aircraft an these accidents are just a statistical anomaly.
With a bandwagon rolling. all sorts will join in - however do not let that lead you to believe the whole thing is rubbish. Rotors ripping off the top of an aircraft carrying people who cannot choose which one they fly in, is a very powerful argument.
Quoting a partial accident record utterly undermines your creditability. Quote the full record or nothing at all. It is the easiest thing in the world to select a 'golden period' and then make an argument from it. Now try the 4 accidents and tell someone that the 10 year mean it is a really. really, safe aircraft an these accidents are just a statistical anomaly.
With a bandwagon rolling. all sorts will join in - however do not let that lead you to believe the whole thing is rubbish. Rotors ripping off the top of an aircraft carrying people who cannot choose which one they fly in, is a very powerful argument.
AAIB S2-2014
"38. In both accidents the emergency lubrication system, once activated,
appeared to have successfully cooled and lubricated the main rotor
gearbox."
Which 4? Just the 4 NS with the 225? The 4 Super Puma 332 & 225 in the NS since the 2012 panic-fest?
When I look at the incidents involving the EC225, frankly, I see nothing unusual compared to other helicopters. There is just less of it.
The numbers tell me that modern types, of which this is one, kill fewer people than older types. There are fewer accidents and it is easier to get out alive.
When I look at the incidents involving the EC225, frankly, I see nothing unusual compared to other helicopters. There is just less of it.
The numbers tell me that modern types, of which this is one, kill fewer people than older types. There are fewer accidents and it is easier to get out alive.
In both cases (DW & CN), although EMLUB had been correctly activated and was functioning correctly, a warning of EMLUB failure was indicated shortly after activation and the crews followed procedure and ditched. It subsequently turned out that there was a design fault in the warning system.
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This will be a never ending debate about safety systems and safety records but stats don't lie!! Currently both the 225 and the 92 each have a single accident causing fatalities. Both types have numerous other incidents/accidents on their records that flaw their safety records. Unfortunately for the 225, it just happens to share its life with the "super puma family." If you could separate it from the family and just look at it, it's quite a safe aircraft statistically.
The 2 bevel gear ditchings of the 225, luckily ended up as good as one could hope for in that situation ... By that, I mean the aircraft made it safely to the water and everyone made it home to their families.
I haven't done any official research on the next comment but since the 225 accident, how many emergency landings has the direct competitor had? How many emergency landings have you guys heard of in total for the other guy? I think there has been a many of right time right place for her so far ... Always seems to be a rig, farmers field, rice paddy, jungle ... Something nearby, to prevent the next big ditching.
The 2 bevel gear ditchings of the 225, luckily ended up as good as one could hope for in that situation ... By that, I mean the aircraft made it safely to the water and everyone made it home to their families.
I haven't done any official research on the next comment but since the 225 accident, how many emergency landings has the direct competitor had? How many emergency landings have you guys heard of in total for the other guy? I think there has been a many of right time right place for her so far ... Always seems to be a rig, farmers field, rice paddy, jungle ... Something nearby, to prevent the next big ditching.