Helicopter crash off the coast of Newfoundland - 18 aboard, March 2009
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That sound like a brilliant design, North America engineering does not go by that they're design strategy is to meet the rule.
Even so an emergency lube system to extend the 30 minute dry run would be a nice option. Just a AMP meter in the S92 would be nice as well, would it be not nice to know where 200KW is going (nearly 300 HP).
CHW
Even so an emergency lube system to extend the 30 minute dry run would be a nice option. Just a AMP meter in the S92 would be nice as well, would it be not nice to know where 200KW is going (nearly 300 HP).
CHW
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Probably more useful and practical than an oil level sensor is the solution some other types have, whereby the two pumps take their feed from different levels within the sump. When the higher one loses its supply it generates a caution and when the lower one loses it supply it generates a warning. This gives a sequence that points directly to oil loss.
30-minute run-dry time would perhaps have allowed 491 to land on Hibernia, but the sad fact is that it still wouldn't have made landfall. I still say the PIC should have ditched, but I can understand why not when the type only had SS4 EFS installed and the SS was at SS4 plus the false and ambiguous data provided by the MRGB flight instruments. Without HUEBA and a good chance of a quick capsize the odds of survival probably would not have been much higher, but at least better than a high velocity impact.
I believe that all the Cougar S92s now have SS6 EFS, noticeable by the addition of step feet on the sponsons.
If the TSB recommendations are enforced to the letter we will not see the S92A retained in NL if SAC do not address their inherent design issues and Achilles' heel on this type.
I didn't see any mention of the S92A mounting feet cracks in the report, even though this is not perceived to be a causal factor on the demise of 491 it is still another clear indication that this MRGB design has other serious design flaws.
Until SAC get their act together on the S92 give me a EC225 or 332L2 with their own specific RIPS functionality (332 apparently has heated mats and slip rings same as the EC225 plus a pneumatic boot on the leading edge on the horizontal stabiliser) so we can fly most of the year up here, or the CH-148 MRGB version in the S92A for our hostile waters. We flew the Super Pumas up here for years in the winter and to my knowledge all they did was wear out their gearboxes frequently and were high maintenance. So much for progress...
Safe flying
Max
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No more flights over rough seas...
Oil companies curtail chopper use over rough seas off Newfoundland
Oil companies curtail chopper use over rough seas off Newfoundland
I hope you're joking HC
And as soon as workload is elevated a bit, eg flying an instrument approach, looking at the system gauges just doesn't happen.
We had a real case of an oil cooler fan failure on an AS332L some time ago, so of course transmission oil temperature rises, maybe a degree every 2 or 3 seconds, but crew did not notice until the high temperature warning light came on maybe 2 minutes later.
Its interesting to compare the diametrically opposite philosophies of SAC and EC in terms of HMI:
SAC likes to give crews as much information as possible (thus maximising the potential for misinterpretation by the crews)
EC knows that pilots are stupid and only gives them the information that they really need to know in a black and white way (or grey and red in the case of the EC225) - giving them any more will only confuse them.
On the 225, the gauges have no markings and mostly the gauge range is grey (no more Ts and Ps in the green!). The extremes of the gauge are red lines. If the gauge touches the red line, its out of limits and a caution light comes on and the numeric value of the parameter appears in yellow or red. But there is no sense of how far into the red it goes since the red line is the end of gauge travel, its either red or its not - you either have to apply the RFM procedure or you don't. You can set it to show the numeric values all the time, but that is only for those of a nervous disposition.
On the EC175 I believe the standard display will not include system gauges - they will only pop up if something goes into an amber or red range.
Being a stupid pilot, I prefer the EC way.
HC
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The TSB report is a tour de force.
Its important not to over concentrate on the indications of oil loss when the root cause is the repeat failure of simple component and a sub-standard gearbox.
However, anyone who does want to analyse the indication aspects need to consider the following:
1) The Amber Caution was followed by a Red Warning so fast that the crew didn't have chance to notice the first (this would not have been a surprise to Sikorsky who afterall wanted the bypas valve activated in just 5s to stop a rapid and catestrophic oil leak)
2) The FSI checklist in use was however written with the assumption that their would be a much more gradual leak (as used in all training scenarios).
3) As a result the NHP had to thumb page thru page to find the Oil P Warning as it wasn't in the index.
4) The fact that there had been 4 oil system S-92 emergencies in the past of which 3 were pump failures and 1 that "was not considered a cause for concern since the problem was attributed to another company's field repair".
5) Sikorsky had concealed that during the 6 August 2002 initial certification loss of lubricant test (when they drained the MGB and to just the 1,3 gallon residual oil) the MGB "suffered a catastrophic failure about 11 minutes after the test was started...due to excessive temperature caused by lack of lubrication".
6) As Brains said: Finding yourself suddenly with zero pressure (say) in the cruise at 9,000 is going to eat up lot of that 11 minutes (as demonstrated) getting to the ground/water.
7) As the AAIB described the S-92 this week, it does have "sub-optimal switch locations and markings" in the cockpit Air Accidents Investigation: Sikorsky S-92A, G-SARC
8) The sea state was at the limits of the basic S-92 floats (as Cougar had not bought the enhanced floats - though they were not available when the S-92 first entered service)
Sikorsky had 6.5 years to address the MGBs shortcomings, the Cougar crew had just seconds.
Its important not to over concentrate on the indications of oil loss when the root cause is the repeat failure of simple component and a sub-standard gearbox.
However, anyone who does want to analyse the indication aspects need to consider the following:
1) The Amber Caution was followed by a Red Warning so fast that the crew didn't have chance to notice the first (this would not have been a surprise to Sikorsky who afterall wanted the bypas valve activated in just 5s to stop a rapid and catestrophic oil leak)
2) The FSI checklist in use was however written with the assumption that their would be a much more gradual leak (as used in all training scenarios).
3) As a result the NHP had to thumb page thru page to find the Oil P Warning as it wasn't in the index.
4) The fact that there had been 4 oil system S-92 emergencies in the past of which 3 were pump failures and 1 that "was not considered a cause for concern since the problem was attributed to another company's field repair".
5) Sikorsky had concealed that during the 6 August 2002 initial certification loss of lubricant test (when they drained the MGB and to just the 1,3 gallon residual oil) the MGB "suffered a catastrophic failure about 11 minutes after the test was started...due to excessive temperature caused by lack of lubrication".
6) As Brains said: Finding yourself suddenly with zero pressure (say) in the cruise at 9,000 is going to eat up lot of that 11 minutes (as demonstrated) getting to the ground/water.
7) As the AAIB described the S-92 this week, it does have "sub-optimal switch locations and markings" in the cockpit Air Accidents Investigation: Sikorsky S-92A, G-SARC
8) The sea state was at the limits of the basic S-92 floats (as Cougar had not bought the enhanced floats - though they were not available when the S-92 first entered service)
Sikorsky had 6.5 years to address the MGBs shortcomings, the Cougar crew had just seconds.
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or a ELS such as the S61 which has a published 120 minutes limit at Vy? (RFM: proceed to nearest landing site at an airspeed of approx 70 -90 knots).
The 120 minutes mentioned in the RFM deals with the maximum time allowed for the electric ELS pump, not how long the MGB can be flown on ELS. The ELS system only supplies oil to the babbitt bearings, which would not survive more than a few seconds without oil, which would then either cause the engine inputs to seize or cause a fire in the magnesium gearbox.....catastrophic.
I hope S61 crews are not lulled into thinking they can fly for 120 mins on ELS.
Last edited by Outwest; 11th Feb 2011 at 22:44.
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HC, I was being somewhat deliberately provocative in my post. I've seen pilots flying in excess of half an hour in the cruise VFR (non existent work load) with an engine oil pressure gauge reading zero and not noticing until it was pointed out to them (engineered to see how long before a response). Perhaps the manufacturers could save a bit of money by just providing idiot lights as in our motor vehicles. A sign we have become a little too comfortable with the reliability of our machinery?
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Not another Sikorsky RFM misconception?
S61 crews need to be aware that on ELS none of the gears (planetary, sun, TTO, etc) are receiving lube oil, so they should consider that the 61 transmission will probably not last much longer than the 92 did.
Being a stupid pilot, I prefer the EC way.
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Perhaps ambiguity is SAC's middle name.
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Outwest, thanks for clarifying, I did go back and look at older posts on the main S92 thread, there was a lot of discussion on ELS just after 491. Here's the link for those interested in refreshing their memory.
http://www.pprune.org/rotorheads/163...ml#post4794848
The statement about the S61 ELS is on page 70 and was your own but I missed the other information wrt. the babbitt bearings and their magnesium gearbox fuel source. At least the S61 ELS comes on automatically and it has one.
I recall reading that the CH-148 ELS was meant to be similar to the EC225 i.e. glycol cooled and 30-minute true run-dry conditions i.e. complete loss of lube oil. For me that is what SAC should have put into the S92 from day 1.
The sad fact is that we're nearly 2 years on after 491 and SAC still haven't provided a solution to the MRGB issues and tried to play the "oh it still meets FAA requirements" card with its steel studs now. Well guess what, it doesn't, never did after Broome, should have been grounded until SAC fixed the problem. What about the premature oil filter false blockages requiring much more extensive filter inspections, which caused additional wear on the titanium studs? The root cause of the mounting feet cracks still hasn't been published, do SAC actually know yet?
I now wonder how long TC will give SAC to address these long-outstanding issues.
At least now thanks to this forum and the TSB report everybody is aware of the real issues.
Perhaps the oil companies should invest in the EC225 and return the S92s as "unfit for required use".
Safe flying
Max
http://www.pprune.org/rotorheads/163...ml#post4794848
The statement about the S61 ELS is on page 70 and was your own but I missed the other information wrt. the babbitt bearings and their magnesium gearbox fuel source. At least the S61 ELS comes on automatically and it has one.
I recall reading that the CH-148 ELS was meant to be similar to the EC225 i.e. glycol cooled and 30-minute true run-dry conditions i.e. complete loss of lube oil. For me that is what SAC should have put into the S92 from day 1.
The sad fact is that we're nearly 2 years on after 491 and SAC still haven't provided a solution to the MRGB issues and tried to play the "oh it still meets FAA requirements" card with its steel studs now. Well guess what, it doesn't, never did after Broome, should have been grounded until SAC fixed the problem. What about the premature oil filter false blockages requiring much more extensive filter inspections, which caused additional wear on the titanium studs? The root cause of the mounting feet cracks still hasn't been published, do SAC actually know yet?
I now wonder how long TC will give SAC to address these long-outstanding issues.
At least now thanks to this forum and the TSB report everybody is aware of the real issues.
Perhaps the oil companies should invest in the EC225 and return the S92s as "unfit for required use".
Safe flying
Max
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Your welcome Max, and I fully support your statement:
I just went back to the posts you mentioned and I think I may have added to the confusion over the S61......again due to some vagueness of the RFM.
I will re-state the S61 MGB has NO demonstrated run dry capability that I'm aware of. The ELS will only give you time (how much no one knows) to make a controlled landing/ditching.
Anyone who has access to the S61 RFM can reference Part 2 Sec 1, page 1-5 for clarification on just what the ELS supplies oil to.
Well guess what, it doesn't, never did after Broome, should have been grounded until SAC fixed the problem.
I will re-state the S61 MGB has NO demonstrated run dry capability that I'm aware of. The ELS will only give you time (how much no one knows) to make a controlled landing/ditching.
Anyone who has access to the S61 RFM can reference Part 2 Sec 1, page 1-5 for clarification on just what the ELS supplies oil to.
Last edited by Outwest; 11th Feb 2011 at 23:41.
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The sad fact is that we're nearly 2 years on after 491 and SAC still haven't provided a solution to the MRGB issues and tried to play the "oh it still meets FAA requirements" card with its steel studs now.
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ATC recording final moments from CBC
Time to Bring Up the Tail Rotor
From the report.
1. The pilot's delay in flipping the bypass switch would have had no effect.
2. The main transmission was not compromised to such an extent to degrade the basic aircraft autorotation capability.
3. The FM states the only response to a loss of tail rotor thrust is immediate autorotation.
4. The transmission failure was a loss of drive to the tail rotor.
5. Loss of tail rotor resulted in extreme attitude excursions which had to have an impact on the ability of the crew to pull off a successful autorotation.
As the S-92 requires a lot of torque to the tail rotor, even in cruise, is this aircraft even capable of surviving a total loss of tail rotor thrust? Did SAC actually test their flight manual procedures to show the aircraft can be successfully autorotated with no tail rotor thrust?
It has been reported that there was an S-92 that lost tail rotor control resulting in a runway landing in Norway. The loss of control does not equate to total loss of thrust as the elastomers can maintain the tail rotor at a thrust level.
All helicopters I have flown in (and there are many) can have a total tail rotor failure in cruise flight and can be guided to a controlled run on landing or an auto into a selected area. I admit none of these have highly canted tail rotors.
The Sultan
1. The pilot's delay in flipping the bypass switch would have had no effect.
2. The main transmission was not compromised to such an extent to degrade the basic aircraft autorotation capability.
3. The FM states the only response to a loss of tail rotor thrust is immediate autorotation.
4. The transmission failure was a loss of drive to the tail rotor.
5. Loss of tail rotor resulted in extreme attitude excursions which had to have an impact on the ability of the crew to pull off a successful autorotation.
As the S-92 requires a lot of torque to the tail rotor, even in cruise, is this aircraft even capable of surviving a total loss of tail rotor thrust? Did SAC actually test their flight manual procedures to show the aircraft can be successfully autorotated with no tail rotor thrust?
It has been reported that there was an S-92 that lost tail rotor control resulting in a runway landing in Norway. The loss of control does not equate to total loss of thrust as the elastomers can maintain the tail rotor at a thrust level.
All helicopters I have flown in (and there are many) can have a total tail rotor failure in cruise flight and can be guided to a controlled run on landing or an auto into a selected area. I admit none of these have highly canted tail rotors.
The Sultan
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Damning
In a dark corner somewhere... Sikorsky tested thier MGB without oil.
It ran for 11 minutes before coming apart.
At 12:15 UTC. at 9000ft Cougar 91's MGB pukes out all its oil....
and exactly 11 minutes later...
They didn't stand a chance.
Godspeed.
It ran for 11 minutes before coming apart.
At 12:15 UTC. at 9000ft Cougar 91's MGB pukes out all its oil....
and exactly 11 minutes later...
They didn't stand a chance.
Godspeed.
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As the S-92 requires a lot of torque to the tail rotor, even in cruise, is this aircraft even capable of surviving a total loss of tail rotor thrust? Did SAC actually test their flight manual procedures to show the aircraft can be successfully autorotated with no tail rotor thrust?
