Sikorsky S-92: Operations
Availability is based upon ships posted to the line. The 96% only means 1 in 25 did not meet its mission. Does not tell you how many are sitting in the hangar getting transmission cases replace, oil filters changed, tail rotors overhauls, etc..
Note: Availability of the Cyclone at Paris is 0%.
The Sultan
Note: Availability of the Cyclone at Paris is 0%.
The Sultan
Light on rotor
The Sultan is correct! More simply put the S-92A is short on rotor. It has been said before on this forum, “the S-92 was proposed as a growth S-70.” As the weight grew the rotor did not follow in proportion. As the gross weight grew form 22,220 lbs in 1993 to its present weight of more than 27,000 lbs. (21.5%) the rotor diameter was increased 2.66 ft. and the rotor speed was increased from 258 to 271 rpm. These fixes were aimed to expedite the fielding of the machine, but may have resulted in some of the present issues.
Dan,
I have to fall back on the CH-53A as a basic design point. It was designed as a 33,000 lb. machine with a six bladed 72 ft. diameter rotor. Anyone with experience in one of these machines will admit that it was fine aircraft. That combination resulted in a fast smooth machine with an abundance of growth potential. Using similar criteria for the S-92, I believe that a five or six bladed system with a rotor diameter similar to the S-61 would be a great starting point.
I have to fall back on the CH-53A as a basic design point. It was designed as a 33,000 lb. machine with a six bladed 72 ft. diameter rotor. Anyone with experience in one of these machines will admit that it was fine aircraft. That combination resulted in a fast smooth machine with an abundance of growth potential. Using similar criteria for the S-92, I believe that a five or six bladed system with a rotor diameter similar to the S-61 would be a great starting point.
Sultan
Please clarify the Ch-148's availabilty % ? It is not actually meant to be flying so how can you calculate an availabilty rate?
Regarding wider S-92 availability, it is really dependend on how you count it. My company counts all unscheduled events in availability figures, so, an unscheduled MGB change for whatever reason would be counted in the availability statistics which in turn are reported to Sikorsky. Scheduled (1500 hour) inspections are not counted as they are predictable events.
Please clarify the Ch-148's availabilty % ? It is not actually meant to be flying so how can you calculate an availabilty rate?
Regarding wider S-92 availability, it is really dependend on how you count it. My company counts all unscheduled events in availability figures, so, an unscheduled MGB change for whatever reason would be counted in the availability statistics which in turn are reported to Sikorsky. Scheduled (1500 hour) inspections are not counted as they are predictable events.
Dan, should I understand your response to henra's question as meaning that you are retired from working at Sikorsky (or a UTC company)?
There is absolutely nothing wrong with loyalty if one had a good experience with a company. For that matter, there is nothing wrong with speaking well of Sikorsky, given how successful many Sikorsky helicopters are.
(UH-60M seems to be following in footsteps very nicely!
)
There is absolutely nothing wrong with loyalty if one had a good experience with a company. For that matter, there is nothing wrong with speaking well of Sikorsky, given how successful many Sikorsky helicopters are.
(UH-60M seems to be following in footsteps very nicely!
)
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Can any one comment on this?
Cougar helicopter cleared after offshore incident - Nfld. & Labrador - CBC News
I've been told it has been treated as significant enougth to report to TSB.
Cougar helicopter cleared after offshore incident - Nfld. & Labrador - CBC News
I've been told it has been treated as significant enougth to report to TSB.
Passengers on a Cougar helicopter got a rougher ride than they wanted last Saturday.
Soon after taking off from the SeaRose Floating Production, Storage, and Offloading (FPSO) facility the helicopter experienced an unplanned increase in pitch and altitude, followed by a decrease in altitude, Husky Energy told the Canada Newfoundland and Labrador Offshore Petroleum Board.
The helicopter crew was able to stabilize the aircraft into a steady hover, after which they performed equipment checks before continuing their flight to St. John's.
The helicopter arrived in St. John's without further problems. It has since been checked over and returned to service.
Husky Technical Advisors are monitory Cougar's investigation into the incident.
Soon after taking off from the SeaRose Floating Production, Storage, and Offloading (FPSO) facility the helicopter experienced an unplanned increase in pitch and altitude, followed by a decrease in altitude, Husky Energy told the Canada Newfoundland and Labrador Offshore Petroleum Board.
The helicopter crew was able to stabilize the aircraft into a steady hover, after which they performed equipment checks before continuing their flight to St. John's.
The helicopter arrived in St. John's without further problems. It has since been checked over and returned to service.
Husky Technical Advisors are monitory Cougar's investigation into the incident.
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S-92
Hi Brian
As part of prelift checks we check "AFCS" mode so it's
unlikely but not impossible
more likely AVC has dropped offline --- sometimes happens
The question of adding a 5th or 6th blade comes up now and again
can anybody tell me why it seems to be so hard or impossible for Sikorsky to come to the same conclusion
With the introduction in of Phase 3 gearboxes
any results/feedback come in yet ?
PV
As part of prelift checks we check "AFCS" mode so it's
unlikely but not impossible
more likely AVC has dropped offline --- sometimes happens
The question of adding a 5th or 6th blade comes up now and again
can anybody tell me why it seems to be so hard or impossible for Sikorsky to come to the same conclusion
With the introduction in of Phase 3 gearboxes
any results/feedback come in yet ?
PV
The AFCS is left ON throughout as it's uses WoW logic to change its status. So shouldn't be an issue. As for the AVC, can't see why that would result in drama - although it plays up, it always tells you!
There seem to be a lot of niggles!! is this aregulatory failure, most of these faults should have been sorted before certification.
"As for the AVC, can't see why that would result in drama - although it plays up, it always tells you!
If the above advertisement for Sikorsky is supposed to impress me......,well it does not.
It is still the noisiest,most vibrating helicopter I flew,and almost nothing has changed in that department over the last 5 years
RT&B does not impact 4/rev levels. The problem with the 92 is too long a blade, too high an rpm, etc. RT&B does not cause vibration hammers to fatigue off the wall and start pounding their way into the fuel cells."
Gear box
Oil filter
"As for the AVC, can't see why that would result in drama - although it plays up, it always tells you!
If the above advertisement for Sikorsky is supposed to impress me......,well it does not.
It is still the noisiest,most vibrating helicopter I flew,and almost nothing has changed in that department over the last 5 years
RT&B does not impact 4/rev levels. The problem with the 92 is too long a blade, too high an rpm, etc. RT&B does not cause vibration hammers to fatigue off the wall and start pounding their way into the fuel cells."
Gear box
Oil filter
You will probably see the 5-bladed S-92B or something to that effect up for the rebid on VXX. The design has been under development for years.
Where do we suppose all the CH-148 contract extension dollars were going?
I also heard rumors that there is a serious cabin-beefing mod design for the 92 in work, chasing the load path from the XMSN all the way down back through the station frames with external straps and whatnot.
I guess the cracking isnt limited to the gearbox feet and has made its way into the airframe as well if they really are going through something this involved.
Where do we suppose all the CH-148 contract extension dollars were going?
I also heard rumors that there is a serious cabin-beefing mod design for the 92 in work, chasing the load path from the XMSN all the way down back through the station frames with external straps and whatnot.
I guess the cracking isnt limited to the gearbox feet and has made its way into the airframe as well if they really are going through something this involved.
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There seem to be a lot of niggles!! is this aregulatory failure, most of these faults should have been sorted before certification
Note that in the NL case the A/C was returned to service the next day. I've heard that the pilots remain suspended pending a TSB investigation.
Link to AAIB report below.
Air Accidents Investigation: Sikorsky S-92A, G-SARC
Safe flying
Max
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SansA
Could the external straps not just be a response to proposed upping of the max gross weight? EC did something similar with the 225.
Sea Rose Incident
Is it correct he CFD will not couple in roll or pitch if selected at below 50 kts?
I've heard that at least one of the crew is no longer with Cougar. I hope this is not true, but if so this brings the following from the TSB report into their 2009 crash into question.
Could the external straps not just be a response to proposed upping of the max gross weight? EC did something similar with the 225.
Sea Rose Incident
Is it correct he CFD will not couple in roll or pitch if selected at below 50 kts?
I've heard that at least one of the crew is no longer with Cougar. I hope this is not true, but if so this brings the following from the TSB report into their 2009 crash into question.
Cougar Helicopters promotes a non-punitive, "just culture" within its organization as per industry recommended best practices for establishing an effective safety management system. Employees are encouraged to report any safety issue, even if it involves a personal mistake, knowing that they will not be penalized for an unintentional error.
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I've heard that at least one of the crew is no longer with Cougar. I hope this is not true, but if so this brings the following from the TSB report into their 2009 crash into question
Here's a link again to the AAIB incident report to refresh memories.
Air Accidents Investigation: Sikorsky S-92A, G-SARC
Hopefully this TSB report will be produced relatively quickly and communicated to all in this industry in a proactive way.
Safe flying
Max
It is my understanding that the two incidents are not connected.
Again, it is my understanding that mishandling (or should that be handling!) of the aircraft when coupled led to the Cougar incident.
To answer Zalt's question, the only 'standard' AP coupling mode that will work in a non-SAR machine below 50 knots IAS is RadAlt. Any roll or pitch coupling will "decouple" when the aircraft is decelerated through 50 knots.
Again, it is my understanding that mishandling (or should that be handling!) of the aircraft when coupled led to the Cougar incident.
To answer Zalt's question, the only 'standard' AP coupling mode that will work in a non-SAR machine below 50 knots IAS is RadAlt. Any roll or pitch coupling will "decouple" when the aircraft is decelerated through 50 knots.
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Any details on an incident last month in GoM involving a failure of horizontal stabilizer fitting?
To prevent cracking of the tail rotor pylon and horizontal at the stabilizer mounting points there is now an ASB which calls for the machined surfaces to be painted with a Teflon coating. Bonding jumper cables are also to be added to maintain electrical bonding.
The ASB has a 250 hour / 6 month implementation period. Considerably higher priority that the infamous Boome oil filter stud ASB.
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Zalt
Thanks for the information. Does anyone actually know what happened in the GOM? Did the stabaliser come off?
I think you will find that any future ASB on the studs would have a far more rapid compliance time.
Thanks for the information. Does anyone actually know what happened in the GOM? Did the stabaliser come off?
I think you will find that any future ASB on the studs would have a far more rapid compliance time.
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Sikorsky Upgrades Gearbox for S-92
It looks like Sikorsky have finally admitted they need to add an auxiliary lube system.
Sikorsky Upgrades Gearbox for S-92 | Aviation International News
Sikorsky Upgrades Gearbox for S-92 | Aviation International News
Sikorsky Upgrades Gearbox for S-92 by Douglas Nelms
Sikorsky is developing a next-generation main gearbox (MGB) with enhanced lubrication capabilities with built-in redundancy systems such as chip detectors and oil scavenge systems, according to Spencer Elani, Sikorsky’s S-92 program manager. “We are continuing to make a lot of improvements to the current gearbox, and to automate some of the features,” Elani said.
The new MGB is part of a program improvement plan to the oil supply system designed to prevent another catastrophic accident such the March 2009 crash of a Cougar Helicopter S-92 into the Atlantic Ocean. The aircraft crashed following oil loss due to failure of the MGB oil-filter bowl assembly.
A key change has been the replacement of the original filter bowl assembly with a new double oil-filter bowl. Six steel studs now secure the assembly to the MGB in place of three titanium studs in the original design. A higher-capacity filter is also part of the new assembly, which has been retrofitted to all S-92s, and is now standard on all new-production S-92s.
The next-generation gearbox will also feature an automatic oil-cooler bypass switch, unipleat oil filter and improved durability with redundant scavenge and an auxiliary/emergency lubrication system. “The aircraft’s gearbox today already has a lot of redundancy,” Elani said. “We’re adding to that to further improve safety.”
Visual and aural warnings of a drop in oil pressure or a failed oil pump indicator will help pilots and crew in the decision-making process.
The March 2009 crash has created an industry-wide controversy as to certification requirements for large Category A transport helicopters.
Current certification requirements of the FAA, EASA and Transport Canada require that the aircraft be able to continue safe flight for at least 30 minutes after the flight crew has detected lubrication system failure or loss of lubrication.
However, there is a provision within that regulation for all three agencies that adds the caveat “unless such failures are [determined to be] extremely remote.” This was the provision under which the S-92 was certified.
An FAA spokesman stated that Sikorsky had initially tried to show that the main gearbox would continue to produce power for 30 minutes after loss of lubrication was detected by a noticeable decrease in oil pressure. “But it failed to do so,” he said.
Sikorsky said that it identified the external oil cooler system as the one component in the main gearbox lubrication system potentially subject to a leak that was not considered extremely remote. The company said that, “with the consent of the FAA,” it incorporated a bypass valve before the oil cooler designed to maintain some oil reserve in the gearbox should that failure occur.
The FAA said that with activation of the bypass valve after sudden massive leakage was detected, “[the S-92] passed the 30-minute test.”
The 30-minute test has now created the highly ambiguous term “run-dry,” but without a clear definition as to whether “run-dry” means totally without any lubrication, or with only residual lubrication, with an auxiliary or emergency lubrication system, or with an auxiliary cooling system.
The FAA spokesman noted that the term “run-dry” is not in the regulation. Instead it states that “residual oil supply or secondary lubrication systems may be used to show compliance.” It was the complete loss of lubrication that caused the problem with the Cougar aircraft, a problem that Sikorsky and the certifying agencies had stated was “extremely remote.”
However, on July 2, 2008, approximately nine months before the Cougar accident, a CHC S-92 experienced sudden loss of oil pressure, putting the CHC crew in a “land immediately” situation. The aircraft landed safely, and an inspection of the main gearbox showed that two of the three MGB oil filter bowl studs had fractured, causing a total loss of oil.
In December 2009 Sikorsky issued an Alert Service Bulletin calling for replacement of the MGB oil filter bowl with a two-piece oil filter bowl held on by six steel studs. The FAA issued an AD effective June 21, 2010. But it still did not call for a 30-minute “run-dry” capability.
TSB Recommends Rule Changes
The Transportation Safety Board of Canada, which investigated the Cougar accident, has issued two recommendations to Transport Canada, the FAA and the EASA regarding a true 30-minute operating capability for Category A transport helicopters.
The first, A11-01, recommends that the “extremely remote” provision of the loss of lubrication certification requirement be removed “for all newly constructed Category A transport helicopters and, after a phase-in period, for all existing ones.”
The second, A11-02, recommends that the FAA “assess the adequacy of the 30-minute main gearbox run-dry requirement for Category A transport helicopters.”
In its response to these recommendations, the EASA simply stated that it acknowledges receipt of the recommendation and that it is “under consideration and the outcome will be communicated (to the TSBC) in due course.”
The FAA’s response reiterated its requirement that the MGB must be able to run for at least 30 minutes with a loss of lubricating oil, “unless a lubrication failure resulting in a loss of lubrication is determined to be ‘extremely remote.’”
It noted that the S-92A had met the 30-minute “loss of lubrication” requirement by using an oil cooler bypass valve, thereby eliminating the most likely sources of leakage. However, the agency also stated that “events that have occurred during the operational use of the Model S-92A, such as the MGB oil filter bowl failure associated with the S-92 Cougar accident, have shown that certain failures not considered during certification testing are more likely than ‘extremely remote.’ The service history therefore does not support the method of compliance that was originally accepted by the FAA at the time of the Model S-92A type certification.”
The FAA said that it will therefore propose a rule change to either clarify or eliminate the ‘extremely remote’ provision of the regulation.
Having said that, the FAA response then went on to state that the agency does not believe it is practical or necessary to require all existing and newly manufactured transport Category A helicopters to be equipped with MGBs that meet the 30-minute loss of lubrication requirement, based on the millions of cumulative flight hours on those helicopters and service histories that show they are operating at a satisfactory level of safety.
Modifying those helicopters with the new MGBs would have a “significant economic impact on the aviation community, with the cost outweighing any improvement in safety,” said the agency.
While it is working on the rule change to clarify or eliminate the ‘extremely remote’ provision, it is “revising guidance material to ensure consistent interpretation and standardized methods of compliance for the current rule,” the FAA spokesman said. The revised guidance is expected to be released for comment next spring.
In its response, Transport Canada said it has initiated with the FAA and EASA “a coordinated formal review” of the rules regarding the 30-minute requirement and the “extremely remote” provision “to reach an international agreement on what changes may be required to the rules.”
Transport Canada also stated that it is accelerating a review of the guidance material referred to in the recommendations to identify “additional direction or clarification for the Canadian certification of Category A helicopters by this fall.”
Eurocopter System
As a method of meeting the FAA and EASA certification requirement to operate 30 minutes without lubrication for its EC225, Eurocopter developed a system consisting of an 11-liter tank of glycol connected to the MGB. If the aircraft experiences a total loss of oil, the glycol will be slowly sprayed into the MGB to reduce the temperature and allow the MGB to function. Eurocopter said that during certification trials, the system demonstrated 52 minutes of operation before the MGB failed. The EC225 was certified and delivered in 2004.
Eurocopter said that its EC175 also has a 30-minute “dry run” capacity, but that MGB protection is based on specific gears treatment providing very high resistance to hot temperature, so [it] does not encompass an additional glycol tank as back-up.”
Eurocopter also noted that no EC225 has ever experienced a loss of oil pressure that would require it to activate the system.
Sikorsky is developing a next-generation main gearbox (MGB) with enhanced lubrication capabilities with built-in redundancy systems such as chip detectors and oil scavenge systems, according to Spencer Elani, Sikorsky’s S-92 program manager. “We are continuing to make a lot of improvements to the current gearbox, and to automate some of the features,” Elani said.
The new MGB is part of a program improvement plan to the oil supply system designed to prevent another catastrophic accident such the March 2009 crash of a Cougar Helicopter S-92 into the Atlantic Ocean. The aircraft crashed following oil loss due to failure of the MGB oil-filter bowl assembly.
A key change has been the replacement of the original filter bowl assembly with a new double oil-filter bowl. Six steel studs now secure the assembly to the MGB in place of three titanium studs in the original design. A higher-capacity filter is also part of the new assembly, which has been retrofitted to all S-92s, and is now standard on all new-production S-92s.
The next-generation gearbox will also feature an automatic oil-cooler bypass switch, unipleat oil filter and improved durability with redundant scavenge and an auxiliary/emergency lubrication system. “The aircraft’s gearbox today already has a lot of redundancy,” Elani said. “We’re adding to that to further improve safety.”
Visual and aural warnings of a drop in oil pressure or a failed oil pump indicator will help pilots and crew in the decision-making process.
The March 2009 crash has created an industry-wide controversy as to certification requirements for large Category A transport helicopters.
Current certification requirements of the FAA, EASA and Transport Canada require that the aircraft be able to continue safe flight for at least 30 minutes after the flight crew has detected lubrication system failure or loss of lubrication.
However, there is a provision within that regulation for all three agencies that adds the caveat “unless such failures are [determined to be] extremely remote.” This was the provision under which the S-92 was certified.
An FAA spokesman stated that Sikorsky had initially tried to show that the main gearbox would continue to produce power for 30 minutes after loss of lubrication was detected by a noticeable decrease in oil pressure. “But it failed to do so,” he said.
Sikorsky said that it identified the external oil cooler system as the one component in the main gearbox lubrication system potentially subject to a leak that was not considered extremely remote. The company said that, “with the consent of the FAA,” it incorporated a bypass valve before the oil cooler designed to maintain some oil reserve in the gearbox should that failure occur.
The FAA said that with activation of the bypass valve after sudden massive leakage was detected, “[the S-92] passed the 30-minute test.”
The 30-minute test has now created the highly ambiguous term “run-dry,” but without a clear definition as to whether “run-dry” means totally without any lubrication, or with only residual lubrication, with an auxiliary or emergency lubrication system, or with an auxiliary cooling system.
The FAA spokesman noted that the term “run-dry” is not in the regulation. Instead it states that “residual oil supply or secondary lubrication systems may be used to show compliance.” It was the complete loss of lubrication that caused the problem with the Cougar aircraft, a problem that Sikorsky and the certifying agencies had stated was “extremely remote.”
However, on July 2, 2008, approximately nine months before the Cougar accident, a CHC S-92 experienced sudden loss of oil pressure, putting the CHC crew in a “land immediately” situation. The aircraft landed safely, and an inspection of the main gearbox showed that two of the three MGB oil filter bowl studs had fractured, causing a total loss of oil.
In December 2009 Sikorsky issued an Alert Service Bulletin calling for replacement of the MGB oil filter bowl with a two-piece oil filter bowl held on by six steel studs. The FAA issued an AD effective June 21, 2010. But it still did not call for a 30-minute “run-dry” capability.
TSB Recommends Rule Changes
The Transportation Safety Board of Canada, which investigated the Cougar accident, has issued two recommendations to Transport Canada, the FAA and the EASA regarding a true 30-minute operating capability for Category A transport helicopters.
The first, A11-01, recommends that the “extremely remote” provision of the loss of lubrication certification requirement be removed “for all newly constructed Category A transport helicopters and, after a phase-in period, for all existing ones.”
The second, A11-02, recommends that the FAA “assess the adequacy of the 30-minute main gearbox run-dry requirement for Category A transport helicopters.”
In its response to these recommendations, the EASA simply stated that it acknowledges receipt of the recommendation and that it is “under consideration and the outcome will be communicated (to the TSBC) in due course.”
The FAA’s response reiterated its requirement that the MGB must be able to run for at least 30 minutes with a loss of lubricating oil, “unless a lubrication failure resulting in a loss of lubrication is determined to be ‘extremely remote.’”
It noted that the S-92A had met the 30-minute “loss of lubrication” requirement by using an oil cooler bypass valve, thereby eliminating the most likely sources of leakage. However, the agency also stated that “events that have occurred during the operational use of the Model S-92A, such as the MGB oil filter bowl failure associated with the S-92 Cougar accident, have shown that certain failures not considered during certification testing are more likely than ‘extremely remote.’ The service history therefore does not support the method of compliance that was originally accepted by the FAA at the time of the Model S-92A type certification.”
The FAA said that it will therefore propose a rule change to either clarify or eliminate the ‘extremely remote’ provision of the regulation.
Having said that, the FAA response then went on to state that the agency does not believe it is practical or necessary to require all existing and newly manufactured transport Category A helicopters to be equipped with MGBs that meet the 30-minute loss of lubrication requirement, based on the millions of cumulative flight hours on those helicopters and service histories that show they are operating at a satisfactory level of safety.
Modifying those helicopters with the new MGBs would have a “significant economic impact on the aviation community, with the cost outweighing any improvement in safety,” said the agency.
While it is working on the rule change to clarify or eliminate the ‘extremely remote’ provision, it is “revising guidance material to ensure consistent interpretation and standardized methods of compliance for the current rule,” the FAA spokesman said. The revised guidance is expected to be released for comment next spring.
In its response, Transport Canada said it has initiated with the FAA and EASA “a coordinated formal review” of the rules regarding the 30-minute requirement and the “extremely remote” provision “to reach an international agreement on what changes may be required to the rules.”
Transport Canada also stated that it is accelerating a review of the guidance material referred to in the recommendations to identify “additional direction or clarification for the Canadian certification of Category A helicopters by this fall.”
Eurocopter System
As a method of meeting the FAA and EASA certification requirement to operate 30 minutes without lubrication for its EC225, Eurocopter developed a system consisting of an 11-liter tank of glycol connected to the MGB. If the aircraft experiences a total loss of oil, the glycol will be slowly sprayed into the MGB to reduce the temperature and allow the MGB to function. Eurocopter said that during certification trials, the system demonstrated 52 minutes of operation before the MGB failed. The EC225 was certified and delivered in 2004.
Eurocopter said that its EC175 also has a 30-minute “dry run” capacity, but that MGB protection is based on specific gears treatment providing very high resistance to hot temperature, so [it] does not encompass an additional glycol tank as back-up.”
Eurocopter also noted that no EC225 has ever experienced a loss of oil pressure that would require it to activate the system.