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Reading this thread it would seem that only CHC and Babcock have rejected bearings. Is this correct? If so what are they doing or not doing that the other UK operator is?
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the preservation oil was normal tgb oil.
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CHC and Babcock seem to be the only ones that have rejected bearings due to visual inspection. Sikorsky have found issues using HUMS with other operators as well. From what I understand, not all these bearings are being removed for over limit exceedances either. Some have been removed for unexplained trends/spikes/rates that they would like to study and learn from. Obviously everyone are on pins and needles.
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Sikorsky have found issues using HUMS with other operators as well. From what I understand, not all these bearings are being removed for over limit exceedances either. Some have been removed for unexplained trends/spikes/rates that they would like to study and learn from.. With the expense to do the inspection and the $4M+ per seat liability, if a reinstalled bearing fails, no rationale person would ever reuse even a slightly degraded bearing or one that is spitting out "false" fault indications. Replacement bearings are relatively dirt cheap. Again if you have to dig to see an issue or rely on someone in the ether to make a maintenance call it is not the operator/maintainer at fault. It is a half-ass HUMS which does not meet OGP expectations. The Sultan |
Sultan - I agree. However, there really is no digging for the information. The true fact is, the original IMD software does not have the detection capabilities of the new SGBA software. Noe does the original SGBA software, which I believe was used in the initial "detailed analysis" have the same detection capabilities as the latest (Jan 10) SGBA software release.
"To my knowledge" the new software has 2 additional condition indicators added to the tool. Believe these are looking a little deeper into the bearing then just a vibration level (rollers to race freq comparisons/rollers to shaft comparisons). The new software requires less intial data points to set the mean data and the thresholds for collecting these points have been lowered to allow this to happen much quicker. Also, additional algorithms for comparing the the latest data point collected to the previous 20 (looking for step changes rather then limit exceedances). On top of all that, Sikorsky has returned the limit to the original 1.75 from 2.5. |
Originally Posted by albatross
(Post 9643016)
Just an aside.
I have always wondered why, in some instances, a part that has worked well for years, suddenly does not. Change in supplier, overhaul process ect? I recall, for example, in the late 70s we suddenly had problems with Allison 250 engines. What had changed? |
What’s the story on hums with the S92 do you get full support as standard, or is it like the EC225 pay through the nose for off the shelf hardware and pay through the nose for prompt backup to problems? Basically a tax/revenue stream on safety. Not acceptable in this day and age.
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Pablo332 - Cant say for sure what kind of cost comes from the technical support side of HUMS but I can say that I have personally never heard any grumbling or negative commentary in regards to the cost so I'm guessing it isn't bad. Having said that, compared to the euroHUMS/IHUMS (332 days, not 225, no experience with 225 HUMS) it does seem to behave much better from an operational stand point. Overall install seems to be much more reliable.
As for user hardware, it's really just the ground station ... Go to the local computer shop and buy a laptop with a PCMIA slot or card reader and off you go. Few hundred quid should do it. |
Originally Posted by Satcomm
(Post 9645871)
Pablo332 - Cant say for sure what kind of cost comes from the technical support side of HUMS but I can say that I have personally never heard any grumbling or negative commentary in regards to the cost so I'm guessing it isn't bad. Having said that, compared to the euroHUMS/IHUMS (332 days, not 225, no experience with 225 HUMS) it does seem to behave much better from an operational stand point. Overall install seems to be much more reliable.
As for user hardware, it's really just the ground station ... Go to the local computer shop and buy a laptop with a PCMIA slot or card reader and off you go. Few hundred quid should do it. |
Originally Posted by Mitchaa
(Post 9646029)
The IMD software picked up on this with a 5hr warning.
SGBA picked up the same. Sikorsky then run it though an enhanced algorithm and found that the 5hr pre warning above could actually be detected around 20hrs before with a tweaked algorithm. This is the basis of the new SGBA patch and the reason why there is a 3hr limitation on flights that continue to use the IMD. There will be a delay, engineering will need retrained on SGBA so it won't be an instant switch over for the companies that are not using it. All operators should have their dedicated HUMS specialists, if they can't solve an issue they then go back to the Sikorsky HUMS team. From my understanding, engineering do not like S92 HUMS as it's based on a bundled up health indicator rather than single condition indicators. The S92 HUMS system very rarely generates alerts, where the other HUMS systems may give out too many. Are the others too sensitive, and is the S92 system too dumbed down? That's the way it feels. Sikorsky only add additional toolbar algorithms post mechanical failures/issues and are not catching things before they break (for the first time) With conventional condition indicators, SO1/SO2 etc you could work out what was wrong with a driveshaft for example, imbalanced, misaligned etc, the S92 HUMS system doesn't really react like that, it bundles all condition indicators together to create a health score and that's perhaps the reason why it may miss quite a few things. What I find staggering is this is being going on 10yrs and Sikorsky have not redesigned the component. With EASA/CAA and now UK operators all affected, I would hope that this will be heavily scrutinised. Sikorsky are only one more incident away from a European grounding on these if this same failure mode happens again and then Sikorsky will be in a whole heap of 'Airbus type' problems. |
AAIB Report - G-WNSR here.
In particular - Initial findings indicate that the failure of this specific bearing was rapid; a period of 4.5 hours had elapsed from the first exceedance of the relevant bearing condition indicator recorded on the operator’s Health and Usage Monitoring System (HUMS) to the point of failure. A routine download of the HUMS was performed on the evening of 27 December 2016 and the helicopter was released to service. A detailed analysis of the data, conducted after the accident, showed that the Tail Gearbox Bearing Energy Analysis limit had been exceeded on 27 December 2016. Courtesy of (NSFW) Rig Workers Rant Right, so the AAIB Report is out on the West Franklin S92 incident and what do we find? The tail rotor bearing went out of its service parameters 4.5 hours before it failed ie. during the previous day's flying. The HUMS data which showed this was downloaded the previous night but had not been analysed before the accident occurred. What the **** is the point of having HUMS on the chopper if nobody is going to look at the data from it? What the **** is the point of the operator, CHC, introducing a measure to ensure that the maximum time between HUMS download and analysis is 5 hours? The chopper will have crashed 30 mins before the deadline expires. Why isn't this data being analysed in realtime? It's not like the technology isn't available! Frequent flyers will also be interested in learning that 4 S-92s failed their checks. None of the Norwegian choppers failed, odd that! Meanwhile .......................................:=.............. :rolleyes: |
Tail Roror installation
How is this tail-rotor installation different from the tail-rotor installation on the black hawk ? ( oil filter installation on the Black hawk has steel bolts s 92 had titanium bolts).
So where did they save weight in the tail rotor installation ? |
How is this tail-rotor installation different from the tail-rotor installation on the black hawk ? |
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I still struggle with the decision to take off a second time, given it was accepted by the crew that full left pedal had been used and it had not arrested the uncommanded yaw. The S92 has very powerful TR authority so any inability to use it must indicate something other than wind effects.
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Originally Posted by 212man
(Post 10092719)
I still struggle with the decision to take off a second time, given it was accepted by the crew that full left pedal had been used and it had not arrested the uncommanded yaw...
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Originally Posted by Mitchaa
(Post 10092709)
So HUMS picked this up the night before but during the analysis the graph was ‘stuck’ and the exceedance wasn’t clear (look at the scaling on the right hand side) and the engineer released the helicopter.
If he had resolved the stuck graph and zoomed in on the data as shown in the additional graph, the exceedances were clear to see and the TGB bearing would have been inspected that night. So the event was totally avoidable and was just sheer luck that the failure happened 6ft above a helideck. Anywhere else and that would have been in the water or in a field. I can see why it happened, but Jesus, it was clear as day, it should never have left Aberdeen that day. I can imagine the engineer having a hard time trying to explain how he missed that. The importance of Human Factors training I suppose. |
Originally Posted by Mitchaa
(Post 10094171)
..No hindsight about it, it was a human error, he shouldn’t have signed for something that he hadn’t done correctly.
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Lack of captaincy
No armchair required here.
Is there an increasing number of incidents/accidents that show a decreasing level of Captaincy in O&G? You can have 1000s of hours going from A-to-B under strict regulations, Met-monitoring, sea state monitoring, rig cloud base reporting, sms devouring conditions - and still not build ‘Captaincy’. Just like the EC155 SNS incident where the ‘captain’ continued despite glaringly obvious indications (and various other cases of ‘push-on-it’s’) the Captain should have parked the aircraft when it turned 90 without his demand. Where was the ‘Co-pilot’ CRM? I suggest if you can’t control an aircraft on lift within 10 degrees on ‘lift’ - regardless of deck turbulence, then you shouldn’t be flying. Especially with the tr auth of a 92. Wtf was the ‘co’ doing? This is from a company that harps on about CRM and glossy safety seminars?? Crews need to grow some preverbials. Captaincy is dead, long live Captaincy! HUMs action and engineer competency/diligence are ‘barriers’ - the accident happened because the crew did not behave like a crew and a lack of good old fashioned CAPTAINCY. |
Problem is, crews are no longer allowed to demonstrate airmanship. Everything on the North Sea is done by a manual which is great until you come across something that is not in the manual. If it is not in the manual then the immediate reaction is to ask a manager. Our ability to dynamically risk assess has been worn away by procedures and rules written by people who have never done it, done it and were useless or self-appointed experts. Unfortunately, when the unusual event happens, neither the manual nor the manager is of any use. Of course, there is a growing feeling that everything Sikorsky is good and everything Airbus is bad. This leads crews into thinking that the S92 is infallible - it ain’t. This is demonstrated on a near daily basis, there are just a lot of them which masks a lot of problems. To miss a HUMS warning is inexcusable, particularly if this kind of thing has happened before. Statistically, we are due another event and with activities levels about to rise without the experience and support of pre-downturn years, everyone needs to be on the ball.
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Problem is, if something goes wrong, as a pilot you need to be able to, firstly, keep focussed on flying the aircraft, and then note the symptoms, make sense of the symptoms, arrive at a likely diagnosis and proceed with an initial course of action. All that before you look at any manual. No room in any of that for consultation with anybody who is not sitting immediately to your left or right. You just can't be diluting that fundamental aspect of piloting.
Something is fundamentally wrong in the North Sea. Why do accidents happen in the NS at the rate they do but, by way of comparison, in 50 years of operational O&G flying in Bass Strait Australia - which has its fair share of bad weather and all those other things - not a single accident in all that time. Just saying. |
Maybe they have larger ‘preverbials’ down under?
Is the licensing route to an ATPL similar ? |
Originally Posted by EESDL
(Post 10095488)
Maybe they have larger ‘preverbials’ down under?
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The short version is that nowadays oil and gas crews are examined at OPC time mostly, not completely, but mostly by TRE’s with only the knowledge of what it says in the big book and no actual common sense. Examinations are all procedural. So neither the captain or copilot in this case really had that much to go on training wise. Add to this that the company in question have been pushed to promote people by virtue of time served and not actual ability which is all that matters to the unions in U.K. and Ireland, jobs for the boys (and girls), which may not be the case in this instance but overall as a result the ethos for captaincy is then degraded in terms of actual ‘CAPTAINCY’ as Julie is suggesting. Combine this with the question of copilot CRM and I can tell you from personal experience in 2 out of the big 3 North Sea companies that CRM stopped when certain captains decided. It is still the case that those who choose to bully their way in the cockpit exist as much as they did 30 years ago, therefore copilot CRM and the ability to interject suffers.
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Originally Posted by cyclic
(Post 10095362)
... ... Of course, there is a growing feeling that everything Sikorsky is good and everything Airbus is bad. ... ...
You mean the Teflon Aircraft Corporation of Stratford Connecticut. The numbers do tell us something different. |
Of course, there is a growing feeling that everything Sikorsky is good and everything Airbus is bad. My opinion with over thirty five years of flying Pumas of different types is that they are trying to stuff too much wine into the bottle. As far as pilot ability is concerned I was once called a dinosaur on this forum because I said that I used to like to fly the odd sector without the autopilot so as to keep in practice. |
Lack of Captaincy and information
Aknowledging the lack of Captaincy, maybe this information could be useful to 'today' crews:
"Additionally, the helicopter manufacturer reviewed their archive of flight data records to determine whether it is an unusual event for a pilot to use full pedal travel in flight. The analysis showed that the use of full pedal was very rare but had occurred in each of the previous events of TRPCS bearing failure(see paragraph 1.18.2). Conclusions from the review were that this cue is available to flight crew prior to bearing failure, but is indicative of a bearing that is already in an advanced state of degradation. Thus, the use of full pedal travel could indicate a need for prompt action to abort a flight and the helicopter manufacturer is considering whether changes to the RFM could be introduced." (Accident Report, pg.52) |
There is a huge difference between checking and training!
It is not the “union” pressure that saw “snot noses” shoved up the food chain by at least one major North Sea Operator. A wave of newly blessed kids with scant experience found themselves the standards setters and it did not always end up in Wine and Roses. |
So the reason this accident happened is down to the crew and their training ?? How do you train pilots and program simulators for something that’s not supposed to happen ? That bearing could give up in a variety of different ways and of course at any flight phase.
Unless Sikorsky can assimilate all the TRPCS event data and confirm that they all failed in exactly the same way and same time frame I don’t see how you can ‘train’ for this event .There are a million different ways a helicopter can have mechanical failure that leads to loss of Main and/ or Tail rotor control ...e.g MR Servo bolt failure or Scissor bearing failure (See recent Sikorsky Safety advisory).Why don’t Sikorsky actually FIX the TRPCS bearing problem ....? Because they still have no root cause for the failure. In the meantime we are all ‘happily’ flying around in them because HUMS ‘might’ pick up on it 😂. Ironic that the 225 is canned because of as yet no proof of root cause meanwhile we are happy to accept this issue on the S92 when the manufacture has done nothing to resolve it. Personally I can’t see why this thread has descended in to a ‘Crew fault/Crap training/‘snot nose’ debate , surely we should remember we are all human and that this crew in the end saved everyone on board and potentially another Facebook campaign to ‘keep the N.Sea 92 free’. |
How does one learn what is abnormal control responses are, how they are manifested, and recognized and a proper action to take upon encountering such abnormal control responses?
Training, experience, combination of both perhaps? How do you set a minimum standard for that especially for new Types? I would suggest the tail rotor control response issue is several orders of magnitude different than that of the 225 shucking the entire main rotor system. |
Originally Posted by chance it
(Post 10117317)
So the reason this accident happened is down to the crew and their training ?? How do you train pilots and program simulators for something that’s not supposed to happen ? That bearing could give up in a variety of different ways and of course at any flight phase.
Unless Sikorsky can assimilate all the TRPCS event data and confirm that they all failed in exactly the same way and same time frame I don’t see how you can ‘train’ for this event .There are a million different ways a helicopter can have mechanical failure that leads to loss of Main and/ or Tail rotor control ...e.g MR Servo bolt failure or Scissor bearing failure (See recent Sikorsky Safety advisory).Why don’t Sikorsky actually FIX the TRPCS bearing problem ....? Because they still have no root cause for the failure. In the meantime we are all ‘happily’ flying around in them because HUMS ‘might’ pick up on it 😂. Ironic that the 225 is canned because of as yet no proof of root cause meanwhile we are happy to accept this issue on the S92 when the manufacture has done nothing to resolve it. Personally I can’t see why this thread has descended in to a ‘Crew fault/Crap training/‘snot nose’ debate , surely we should remember we are all human and that this crew in the end saved everyone on board and potentially another Facebook campaign to ‘keep the N.Sea 92 free’. |
“I would suggest the tail rotor control response issue is several orders of magnitude different than that of the 225 shucking the entire main rotor system.”
And I would suggest that it wasn’t just a ‘tail rotor control response’ issue. It was a mechanical failure of the Tail rotor pitch control shaft bearing. It’s not just the fact you lose control of the Tail rotor but more importantly the forces involved . Imagine the damage done to the TGB and the vibration to the whole assembly if this had happened in the cruise on the way home . Could these forces have led to eventual break up of the TGB due to heat and vibes if sustained ? Leading to loss of the TGB/TRH and blades ? In my opinion in all the instances of this failure the crews and A/C got lucky as they were all on final approach or close to a landing site . Even titling this as an ‘Unexpected Control response’ was underplaying it in my opinion, and I was shocked this was the title of the news flash distributed to N.Sea operators when it happened. Which ever way you want to view it this is a Nasty accident and for a problem that hasn’t gone away. Hums is only as good as the people deciphering it. But if people want to continue thinking this aircraft is somehow safer than a 225 then carry on ! I fly it every day and I know it’s just another helicopter... |
Originally Posted by Jimmy.
(Post 10117493)
I think we may be comparing apples and oranges here. The report is clear about the human error on interpreting the HUMS data (available the night before the accident). Now, a HUMS download and analysis is made after each flight. Despite the gravity of a TR control failure, it was detectable (4.75hrs and the full left pedal) and quite different than loosing the MR without warning.
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If you’ve read the AAIB reports on G-REDL and the other two bevel gear failures in the 225’s in 2012 you would also note that HUMS actually picked up these failures several hours before too |
The EC225 bevel gear debacle is not why they are currently not being used (although it didn't help!), it is because LN-OJF suffered a catastrophic failure of the MGB that was not and cannot be detected by HUMS or any maintenance practice. This is compounded by no definitive root cause being identified.
Airbus did themselves no favours during all of the EC225 woes with their public denial and mud slinging, rather than being open and honest or even just saying very little. With the current S92 issue, we have a HUMS process that has been shown to work. The HUMS did it's job, but the alert was missed (not for the first time by CHC UK). HUMS itself has been subsequently modified to make it more "user friendly". As mentioned earlier, Sikorsky are now working on a suitable modification. Chance It - the general negative tone of your messages are worrying. I suspect you are in the wrong job if this is carried into the cockpit every day! Or perhaps you just need to sober up on a Saturday morning and take a deep breath :E:E:E |
Originally Posted by Apate
(Post 10117906)
The EC225 bevel gear debacle is not why they are currently not being used (although it didn't help!), it is because LN-OJF suffered a catastrophic failure of the MGB that was not and cannot be detected by HUMS or any maintenance practice. This is compounded by no definitive root cause being identified.
Airbus did themselves no favours during all of the EC225 woes with their public denial and mud slinging, rather than being open and honest or even just saying very little. With the current S92 issue, we have a HUMS process that has been shown to work. The HUMS did it's job, but the alert was missed (not for the first time by CHC UK). HUMS itself has been subsequently modified to make it more "user friendly". As mentioned earlier, Sikorsky are now working on a suitable modification. “Chance It - the general negative tone of your messages are worrying. I suspect you are in the wrong job if this is carried into the cockpit every day! Or perhaps you just need to sober up on a Saturday morning and take a deep breath” :E:E:E Apate , for negativity read realism. It seems ok to berate the Puma on this forum but to even question the S92 one gets accused of being drunk ? |
the argument is moot when the norwegian themselves called the fault on EC before even finding evident and EC duly complied with demonstration that it is very unlikely the few early theories the norwegian thought were the root cause to the event. The continuing no finding only proof that it has nothing to do with the design and build. Only people with agenda is pushing such idea till today.
talking about HUMS, it is not as easy as some people here would like it to be. It is until today still a brilliant idea that never been reliable in actual operation. No matter the system from which OEM attached with which OEM's frame, they are all plague with noise and fault reading. It is very easy for the OEM and top expert in the investigation to point out the "obvious". But to the people on the floor with all kinds of factor in effect, human factor just bound to happen. |
What is missing from HUMS is something that we wanted to have when it first started in the 1980s. A light in the cockpit which would say.
DO NOT FLY THIS HELICOPTER or LAND AS SOON AS POSSIBLE |
What is missing from HUMS is something that we wanted to have when it first started in the 1980s. A light in the cockpit which would say. DO NOT FLY THIS HELICOPTER or LAND AS SOON AS POSSIBLE |
I said LAND, not DITCH it.
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