S92 "unexpected control responses"
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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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.
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
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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.
"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.
Last edited by Satcomm; 18th Jan 2017 at 13:27.
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?
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?
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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.
Last edited by Pablo332; 18th Jan 2017 at 15:58.
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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.
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.
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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.
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.
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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.
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 -
Downloaded and released by not analysed until after the fact?
Courtesy of (NSFW) Rig Workers Rant
Sounds like real time analysis is supposed to be the fix if you drink the Kool Aid on offer by SK at HAI.
Meanwhile .......................................
.............. 
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.
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.
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!
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 .......................................
..............
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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 ?
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 ?
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.
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.
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.
Sure, as pilots we need to rely on other people to do their job properly. Despite this, ultimately the pilot is responsible for the final disposition of the aircraft. If I was flying an aircraft that did an unexpected 45 degree right turn in the hover that was not arrested with full left pedal I would most certainly be parking the bus on that very spot and calling one of those aforementioned other people to deal with it.
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.
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.
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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.