Sikorsky S-92: From Design to Operations
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nbl is right when he posted, "I suggested the line line between doing what the rule book says and using your own judgement is very fine. Ask any passing lawyer."
The best I can say is that between us pilots, there should be an understanding that when the guy comes home and then gets faced by the lawyers, he gets an A+ anyway. I told a lawyer once, on the stand, that when a lawyer makes a mistake, it is a letter in a file somewhere, when a pilot makes one, we get to go to court. The judge gave me a dirty look.
Having made my living writing the flight manuals, I can say that they are not written as if they envision all possible emergencies.
The best I can say is that between us pilots, there should be an understanding that when the guy comes home and then gets faced by the lawyers, he gets an A+ anyway. I told a lawyer once, on the stand, that when a lawyer makes a mistake, it is a letter in a file somewhere, when a pilot makes one, we get to go to court. The judge gave me a dirty look.
Having made my living writing the flight manuals, I can say that they are not written as if they envision all possible emergencies.
I just wanted to say that the fact that this incident occured when I was in the vicinity - Brunei and Mulu - is sheer co-incidence. Honest guv! But I might have to plead guilty to scratching "HC wuz ere" on the paintwork.
Well done to 212 and his colleague for making a safe landing. Anyone who is of the opinion that they did not do absolutely the correct thing is...
Something I had not previously thought about was the difference between having to make an emergency landing whilst flying over the N Sea on a crap night vs flying over primary jungle - the former, you can land in 1 piece and have a modest chance of survival. The latter, you touch down in the canopy and then its 200' to fall without any rotor blades. That is unlikely to be survivable. So in fact flying over primary jungle is much less safe than over the N Sea. Talk about a hostile environment!
It seems to be nothing to do with 30mins dry running time. If a gearbox is going to fail, it doesn't matters whether its a 225 with 30mins in the RFM or a 92 without. You have to land before the bits stop going round and if you wait till the graunching noises, unless you are already in the IGE hover its likely to be too late.
In 1981 Bristow lost a SA330 Puma from transmission failure over the jungle of Sarawak. Everyone died. I am just really glad that this had a safe outcome, the rest is largely irrelevant.
HC
Well done to 212 and his colleague for making a safe landing. Anyone who is of the opinion that they did not do absolutely the correct thing is...
Something I had not previously thought about was the difference between having to make an emergency landing whilst flying over the N Sea on a crap night vs flying over primary jungle - the former, you can land in 1 piece and have a modest chance of survival. The latter, you touch down in the canopy and then its 200' to fall without any rotor blades. That is unlikely to be survivable. So in fact flying over primary jungle is much less safe than over the N Sea. Talk about a hostile environment!
It seems to be nothing to do with 30mins dry running time. If a gearbox is going to fail, it doesn't matters whether its a 225 with 30mins in the RFM or a 92 without. You have to land before the bits stop going round and if you wait till the graunching noises, unless you are already in the IGE hover its likely to be too late.
In 1981 Bristow lost a SA330 Puma from transmission failure over the jungle of Sarawak. Everyone died. I am just really glad that this had a safe outcome, the rest is largely irrelevant.
HC
DECUFAULT, where the pictures?
It is a nice change to have an offshore crew manage to get into a "confined" area. Usually something reserved for the "loggers". I guess there was still enough room left over to get the 212 in beside them.
BTW, I still haven't seen anything posted to indicate exactly what the problem was that the pilots thought they had. 212man posted a picture of a screeen and posed a hypothetical question. Was this what they were looking at in the cockpit (complete with the white haze)?
How far away were they from any airport, or shopping mall parking lot? My impression from reading the posts is that they were over solid triple layer jungle canopy in every direction for a 100 miles, save for that tiny cleared patch.
curious minds - not in NL's words, trying to pprune anyone to death.
malabo
It is a nice change to have an offshore crew manage to get into a "confined" area. Usually something reserved for the "loggers". I guess there was still enough room left over to get the 212 in beside them.
BTW, I still haven't seen anything posted to indicate exactly what the problem was that the pilots thought they had. 212man posted a picture of a screeen and posed a hypothetical question. Was this what they were looking at in the cockpit (complete with the white haze)?
How far away were they from any airport, or shopping mall parking lot? My impression from reading the posts is that they were over solid triple layer jungle canopy in every direction for a 100 miles, save for that tiny cleared patch.
curious minds - not in NL's words, trying to pprune anyone to death.
malabo
Malabo,
it wasn't THAT confined, more obstacles to watch out for and fnding a firm surface that wasn't water logged. Both of us had spent 8+ years in Nigeria (mainly Delta sites), so weren't too phased by landing off field (or not on a platform.)
The EICAS I showed was what we had prior to landing, complete with smell and haze.
The nearest aiport was 4.9 nm away (we could see the DME on the ground!) but having spent longer than we aleady wanted remaining airborne, we weren't about to try our luck for much longer. Besides; you don't get a lot of sympathy for going tech at holiday resort!
For those S-92 pilots that didn't know, note how the MGB Temp gauge just stops indicating, the numbers are replaced by dashes and an orange M appears, above a certain temperature! Can't find reference to that in the RFM or AMM (or FSI PTM.)
it wasn't THAT confined, more obstacles to watch out for and fnding a firm surface that wasn't water logged. Both of us had spent 8+ years in Nigeria (mainly Delta sites), so weren't too phased by landing off field (or not on a platform.)
The EICAS I showed was what we had prior to landing, complete with smell and haze.
The nearest aiport was 4.9 nm away (we could see the DME on the ground!) but having spent longer than we aleady wanted remaining airborne, we weren't about to try our luck for much longer. Besides; you don't get a lot of sympathy for going tech at holiday resort!
For those S-92 pilots that didn't know, note how the MGB Temp gauge just stops indicating, the numbers are replaced by dashes and an orange M appears, above a certain temperature! Can't find reference to that in the RFM or AMM (or FSI PTM.)
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Well Done 212
Well done 212 man. As has been said, it's always easy to criticise from the comfort of an armchair having had time to pontificate on a situation which a crew had to make a reasoned decision on in seconds. At the end of the day, you landed an aircraft safely and with no casualties, so you made the right decision. Quality will out 
. Good training, a good attitude and consistently high standards always show through. Again, well done.
. Good training, a good attitude and consistently high standards always show through. Again, well done.
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soggyboxers said, "Good training, a good attitude and consistently high standards always show through."
Well said, and also one can ask, "when will a computer be able to do it that well?"
Well said, and also one can ask, "when will a computer be able to do it that well?"
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For those S-92 pilots that didn't know, note how the MGB Temp gauge just stops indicating, the numbers are replaced by dashes and an orange M appears, above a certain temperature! Can't find reference to that in the RFM or AMM (or FSI PTM.)
Well done on the actions you took, based on our EOP's I would have done the same. With a new aircraft you are better to be safe than sorry.
NW
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Oil Temp Indications
212Man
Can you just clarify if the indications following loss of MGB oil. Are those temp indications valid ones given the lack of oil to measure the temp? Could the blanks indicate 'uncertain values'? Always a dilemma when looking for 'double indications' in the early stages.
The only example of MGB oil loss that I am familiar with in any detail involved a 412 2 years ago in S. America. Chaffed pressure line caused total loss of lube oil during offshore flight. Crew failed to cancel master caution so did not observe the subsequent illumination of chip light during their dash to the beach. MGB seized but they were able to enter autorotation and crash-landed in the sea with zero fatalities. The result indicates that although they did a lot wrong the crew did enough right to survive this nightmare.
Is the 139 the only helo to have completed the JAR/FAR29 MGB 'run dry' test satisfactorily?
Are gearboxes designed so that autorotation with always be possible following seizure of the most vulnerable components?
G
Can you just clarify if the indications following loss of MGB oil. Are those temp indications valid ones given the lack of oil to measure the temp? Could the blanks indicate 'uncertain values'? Always a dilemma when looking for 'double indications' in the early stages.
The only example of MGB oil loss that I am familiar with in any detail involved a 412 2 years ago in S. America. Chaffed pressure line caused total loss of lube oil during offshore flight. Crew failed to cancel master caution so did not observe the subsequent illumination of chip light during their dash to the beach. MGB seized but they were able to enter autorotation and crash-landed in the sea with zero fatalities. The result indicates that although they did a lot wrong the crew did enough right to survive this nightmare.
Is the 139 the only helo to have completed the JAR/FAR29 MGB 'run dry' test satisfactorily?
Are gearboxes designed so that autorotation with always be possible following seizure of the most vulnerable components?
G
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For the record, this Did occour over the North Sea with a Norsk Helikopter S-92, 3 years ago about 5-6 min. from an oil rig. The indications of the failure looks very similar, loss of MGB oil P, but stil about 5-6 psi. after bypass.
As a result Sikorsky has been redesigning the MGB pump systems, which should be installed in later machines or overhaul.
212man, does the failure look familiar or is it a new type of failure that occured on your machine?
As a result Sikorsky has been redesigning the MGB pump systems, which should be installed in later machines or overhaul.
212man, does the failure look familiar or is it a new type of failure that occured on your machine?
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The "chip system fault" is interresting. Is this a correct picture of what the situation was before or after landing? (Show OBE, only on gnd)
Red MGP comes on below 30psi, so there is still oil left. The Red M is new to me as well. Another software update not in the books....
I don`t expect there was any time to look at the HLTH page or maintenance page?
Looking forward to learn the sequence of breakdown and indications with something we could all learn from.
Good Job.
Red MGP comes on below 30psi, so there is still oil left. The Red M is new to me as well. Another software update not in the books....
I don`t expect there was any time to look at the HLTH page or maintenance page?
Looking forward to learn the sequence of breakdown and indications with something we could all learn from.
Good Job.
Geoffers,
it was not an oil loss situation. The loss of Temp indications indicates an offscale condition: the temperature rose rapidly, then reached a value (unknown or described in the AMM) and then the indications you see appeared in lieu of a valid display.
Airjock, no: not the same as the Norsk machine. That was a vespel spline failure in a pump which, with an associated lack of check valve from the other pump output, allowed the oil to be circulated through the failed pump rather than the main system. In the main, the pressure held around 44 psi until the later stages when it dropped to 25 psi.
The red oil Pressure band starts at 35 psi, but the Warning (not caution) doesn't come on till 24 psi.
The CHIP SYS FAULT appears to be a result of the input chip detector starting to 'dissolve'!
it was not an oil loss situation. The loss of Temp indications indicates an offscale condition: the temperature rose rapidly, then reached a value (unknown or described in the AMM) and then the indications you see appeared in lieu of a valid display.
Airjock, no: not the same as the Norsk machine. That was a vespel spline failure in a pump which, with an associated lack of check valve from the other pump output, allowed the oil to be circulated through the failed pump rather than the main system. In the main, the pressure held around 44 psi until the later stages when it dropped to 25 psi.
The red oil Pressure band starts at 35 psi, but the Warning (not caution) doesn't come on till 24 psi.
The CHIP SYS FAULT appears to be a result of the input chip detector starting to 'dissolve'!
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OIl temp conundrum
212man
If the pressure was low and the oil loss minimal then I guess your circulation has been compromised so my question remains - How accurate will the temp indications be if the circulation has failed? It will almost certainly depend on where the sensor is located in relation to the component(s) generating the most heat.
When gearboxes are designed are these various failure modes taken into account given that you are looking for multiple indications to confirm a problem?
G
If the pressure was low and the oil loss minimal then I guess your circulation has been compromised so my question remains - How accurate will the temp indications be if the circulation has failed? It will almost certainly depend on where the sensor is located in relation to the component(s) generating the most heat.
When gearboxes are designed are these various failure modes taken into account given that you are looking for multiple indications to confirm a problem?
G
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Is there any visual signs of high temperature and where was the leaks, because the oil did not just evaporize, or??
At what stage of the flight did this occur?
Hope you will follow up with the cause of this very interresting occurence.
At what stage of the flight did this occur?
Hope you will follow up with the cause of this very interresting occurence.
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How do you post an image as a file.. without using URL? Tried the Search function but don't see the 'Manage attachment' Button
Last edited by anomkneeus; 2nd Feb 2008 at 13:22.
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Bernouli's what
Just "borrowed" this photo. I don't think I'll be anonymous for long!
Image: http://photos-173.ll.facebook.com/ph...19854_1522.jpg
Upset someone?
Image: http://photos-173.ll.facebook.com/ph...19854_1522.jpg
Upset someone?
