Sikorsky S-92: [Archive Copy]
HC,
Nick is a former Gunship pilot....a Cobra pilot in fact....thus one cannot expect a Gunny of Greek origin to get the spelling right on the first go. For crying out loud Man, he trips over his own shoelaces.(Probably how he got selected for Cobras....or on his inability to fly formation.) Let it suffice that he understands the concepts ,which in some cases around this rodeo, does not apply to all parties to the argument.
Nick,
Remember the old cowboy saying...."When you ride for the brand....ride for the brand."
One should not criticize a cowboy's loyalty.
Nick is a former Gunship pilot....a Cobra pilot in fact....thus one cannot expect a Gunny of Greek origin to get the spelling right on the first go. For crying out loud Man, he trips over his own shoelaces.(Probably how he got selected for Cobras....or on his inability to fly formation.) Let it suffice that he understands the concepts ,which in some cases around this rodeo, does not apply to all parties to the argument.
Nick,
Remember the old cowboy saying...."When you ride for the brand....ride for the brand."
One should not criticize a cowboy's loyalty.
Thankyou SAS for coming once again to Nick's rescue - kind of sweet the way you Yanks stick together (and let's face it, he needs the support). But haven't you dropped him in it just a bit by pointing out his Greek origin? Who else could we expect to be familiar with Greek Mythology that a Greek person?
But seriously, of course I can understand his brand loyalty. My question, as it stated, was not intended to be a subtle (or otherwise) dig at the 92. I don't need to slag it off any more, its reputation precedes it! It was out of genuine interest as I have never operated a fully de-iced helicopter, and never seen a flight manual supplement for a full de-icing system. Here on the N Sea we cope adequately with the famous British Limited Icing Clearance.
One of my policies is that I never take manufacturer's sales talk at face value, so it will be interesting to find out whether the S92 and / or the EC de-icing systems are fully duplex with no common parts that could fail and bring both "channels" down.
And another thing - are you familiar with the meaning of the expression "cowboy" to a Brit?
HC
But seriously, of course I can understand his brand loyalty. My question, as it stated, was not intended to be a subtle (or otherwise) dig at the 92. I don't need to slag it off any more, its reputation precedes it! It was out of genuine interest as I have never operated a fully de-iced helicopter, and never seen a flight manual supplement for a full de-icing system. Here on the N Sea we cope adequately with the famous British Limited Icing Clearance.
One of my policies is that I never take manufacturer's sales talk at face value, so it will be interesting to find out whether the S92 and / or the EC de-icing systems are fully duplex with no common parts that could fail and bring both "channels" down.
And another thing - are you familiar with the meaning of the expression "cowboy" to a Brit?
HC
Well now pardner....cannot say I do....but then we live in a multi-national world last I checked and the English language has many idioms and slang definitions thus it could mean most anything convenient to the user I reckon.
I can assure you however that there is a world of difference between a real life, rooting tooting, lariat throwing Cowboy than some fancy dress and affected drawl.
Where real Cowpokes dwell we have a saying...."Never kick fresh Cow ****."
I can assure you however that there is a world of difference between a real life, rooting tooting, lariat throwing Cowboy than some fancy dress and affected drawl.
Where real Cowpokes dwell we have a saying...."Never kick fresh Cow ****."
Errrrrrr HC,
In cowboy talk....that translates to "Don't worry about biting off more than you can chew....your mouth is probably a whole lot bigger'n you think."
In cowboy talk....that translates to "Don't worry about biting off more than you can chew....your mouth is probably a whole lot bigger'n you think."
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Now, now now, calm down guys
The humerous light-hearted abuse was amusing but now we are descending into some really unnecessary territory.
Some interesting stuff has come out of the (competitive) dialogue in the past so why don't you two just apologise to each other for overstepping the mark and then Nick explain how the system is designed.
Come on guys, it's Easter, give us a break!!!
G
PS - I think George Bush would advise the use of "duplexitousness" instead of "duplexity" but then we always were two nations divided by a common language as in don't ask for a 'fag' (cigarette) when in the US or you will get more than you bargained for.
Some interesting stuff has come out of the (competitive) dialogue in the past so why don't you two just apologise to each other for overstepping the mark and then Nick explain how the system is designed.
Come on guys, it's Easter, give us a break!!!
G
PS - I think George Bush would advise the use of "duplexitousness" instead of "duplexity" but then we always were two nations divided by a common language as in don't ask for a 'fag' (cigarette) when in the US or you will get more than you bargained for.
HC, if you can wait till after the 23rd I'll e-mail you the relevant pages from the RFM (in the UK now so don't have it to hand).
I think the question you raise has some merit but equally has a pretty obvious answer; attempt to fly out of icing conditions! I wonder whether fixed wing a/c have specific advice for similar situations? Somehow I doubt it.
I guess other analogies include flying above Vne for flotation gear inflated or power off: Do you limit your speed on the off chance the floats inflate inadvertently or you have a double engine failure?
Best to fly somewhere with no icing!
I think the question you raise has some merit but equally has a pretty obvious answer; attempt to fly out of icing conditions! I wonder whether fixed wing a/c have specific advice for similar situations? Somehow I doubt it.
I guess other analogies include flying above Vne for flotation gear inflated or power off: Do you limit your speed on the off chance the floats inflate inadvertently or you have a double engine failure?
Best to fly somewhere with no icing!
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Quite right 212man, A330/340 says 'Avoid Icing Conditions' if and anti-icing system goes down due to a primary system failure (usually to do with bleed air availability). There are no duplex systems on our (modern) fw. The difference is on the NS and other areas (before the Canadians scream) is the length of exposure. Usually we pass through the icing pretty quickly in an Airbus, the biggest icing accumulation I have ever seen was on that weird toadstool nailed to the side of a Super Puma (or Tiger in case there are more sensitive souls out there).
TOD
TOD
212man - thanks for the offer of the rfm pages, I would appreciate a look-see and I can wait til the 23rd!
As you say, one option is to fly out of the icing conditions but if you make it a requirement to have somewhere to go, surely you are back in the realms of the limited icing clearance and so the full de-icing isn't giving you much advantage?
On the other hand, if the rfm (any rfm, not just the 92's) allows you, for instance, to fly in icing conditions in a mountainous region where surface temperatures are below zero and cloud base is well below msa, but its not a fully duplex system, surely that's a gotcha if (when) it fails?
TOD - interesting that the airbus only has a simplex system. Of course you make a fair point that you are normally above all the crap that we mortals fly in, but if the system fails at cruising FL, and you are above 8/8 icing clouds, how do you comply with the flight manual?
Answering my own question, perhaps you have the range / speed to go somewhere else where there isn't 8/8 icing clouds?
And I suppose it could be argued that the fixed wing system should be more reliable as surely its easier to de-ice bits when they are not whirling round and round!
To 212's other points I would say that you should have the ability to cope with a single failure but not a double. ie you should not fly above float vne with the system armed, as a single failure (the firing system) would cause you a problem. However if not armed, its OK to fly above that speed (just as well on a SKY machine!) as you would have to have a problem with both the arming and the firing systems (assuming a well designed system!) before a problem occured. But with the Vne power off, its OK to fly above that because you would have to have a double simultaneous engine failure for there to be a problem and that is extremely unlikely. Perhaps not impossible but then consider where the limit comes from? I don't know that answer but perhaps it is just because that is as far as the test pilots wanted to go with no engines and an eyewatering rate of descent, or because the handling at that speed is not nice. But its probably not because anything catastrophic would happen in the few seconds it took to lose the speed. But inflating floats above float Vne could be catastrophic in various ways such as the floats ripping off and hitting rotors, or an uncontrollable pitching up/down etc. Not a very scientific analysis I know so I'll stop now!
HC
As you say, one option is to fly out of the icing conditions but if you make it a requirement to have somewhere to go, surely you are back in the realms of the limited icing clearance and so the full de-icing isn't giving you much advantage?
On the other hand, if the rfm (any rfm, not just the 92's) allows you, for instance, to fly in icing conditions in a mountainous region where surface temperatures are below zero and cloud base is well below msa, but its not a fully duplex system, surely that's a gotcha if (when) it fails?
TOD - interesting that the airbus only has a simplex system. Of course you make a fair point that you are normally above all the crap that we mortals fly in, but if the system fails at cruising FL, and you are above 8/8 icing clouds, how do you comply with the flight manual?
Answering my own question, perhaps you have the range / speed to go somewhere else where there isn't 8/8 icing clouds?
And I suppose it could be argued that the fixed wing system should be more reliable as surely its easier to de-ice bits when they are not whirling round and round!
To 212's other points I would say that you should have the ability to cope with a single failure but not a double. ie you should not fly above float vne with the system armed, as a single failure (the firing system) would cause you a problem. However if not armed, its OK to fly above that speed (just as well on a SKY machine!) as you would have to have a problem with both the arming and the firing systems (assuming a well designed system!) before a problem occured. But with the Vne power off, its OK to fly above that because you would have to have a double simultaneous engine failure for there to be a problem and that is extremely unlikely. Perhaps not impossible but then consider where the limit comes from? I don't know that answer but perhaps it is just because that is as far as the test pilots wanted to go with no engines and an eyewatering rate of descent, or because the handling at that speed is not nice. But its probably not because anything catastrophic would happen in the few seconds it took to lose the speed. But inflating floats above float Vne could be catastrophic in various ways such as the floats ripping off and hitting rotors, or an uncontrollable pitching up/down etc. Not a very scientific analysis I know so I'll stop now!
HC
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Hi HC, the whole thing hangs around the typical use of weasel words like 'Avoid', it doesn't say 'Prohibited'. If as you say we expect any icing in the TMA then there is a little line in the QRH which asks us to increment the approach speed by 10 kts in case we believe there is ice buildup on unheated surfaces. If the ice detection system picks up any deposit then the 'Severe Icing Detected' warning is in amber - not red, indicative of the level of threat that Airbus sees in the situation.
Also as you indicate, the deicing system doesn't accelerate and decelerate on an Airbus by 130kts 280 times a min, also it is rarely the system it's self that causes the problem but some primary failure leading to the restriction of available bleed air, since this is what typically does the removal. I suppose on that basis - that little tailess reaction helicopter the French built - the Djinn I think it was called - should remain pretty ice free no matter the circumstances (unless the engine failed, then it's pretty cut and dried)
Generally though there is plenty of warning that you are liable to encounter icing from other traffic and the ATIS and typically we find for out ops that this is only a couple of thousand feet thick.
TOD
Also as you indicate, the deicing system doesn't accelerate and decelerate on an Airbus by 130kts 280 times a min, also it is rarely the system it's self that causes the problem but some primary failure leading to the restriction of available bleed air, since this is what typically does the removal. I suppose on that basis - that little tailess reaction helicopter the French built - the Djinn I think it was called - should remain pretty ice free no matter the circumstances (unless the engine failed, then it's pretty cut and dried)
Generally though there is plenty of warning that you are liable to encounter icing from other traffic and the ATIS and typically we find for out ops that this is only a couple of thousand feet thick.
TOD
HC
The system is duplex including 2 controllers (1 running in standby, usual system). Actions in the event of failure depend on what's failed, but in the worst case it requires vacate icing as soon as possible. I know that the issue you raised was one that concerned the EASA team, which is why the EASA approval took so long. I haven't heard whether they have put any additional restrictions on the clearance. Drop round some time if you want and I will show you the relevant bits of the RFM.
Cheers
Steve
The system is duplex including 2 controllers (1 running in standby, usual system). Actions in the event of failure depend on what's failed, but in the worst case it requires vacate icing as soon as possible. I know that the issue you raised was one that concerned the EASA team, which is why the EASA approval took so long. I haven't heard whether they have put any additional restrictions on the clearance. Drop round some time if you want and I will show you the relevant bits of the RFM.
Cheers
Steve
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The redundancy of the S92 de-ice extends to all principal components. The sensors which detect the ice, the computer controllers (as steve_oc says), and the electric power supply. There are two independant busses, and each large generator is able to hold up the de-ice load after the other fails.
Also, the aircraft was shown to be able to maintain safe flight control after many minutes with it all turned off, as a last resort. I believe it was at least 15 minutes.
Airplanes have simplex systems based on exposure time, since the climb and descend quickly thru the icing region of the sky, while helos flog through it.
I am not sure if the 225 will have a de-ice system, I do recall Helicomparitor telling us why de-ice was not necessary, back when the French were not planning to install it. I think I heard that the 225 was now installing such a kit, as part of its need to meet the market that has been redefined.
Also, the aircraft was shown to be able to maintain safe flight control after many minutes with it all turned off, as a last resort. I believe it was at least 15 minutes.
Airplanes have simplex systems based on exposure time, since the climb and descend quickly thru the icing region of the sky, while helos flog through it.
I am not sure if the 225 will have a de-ice system, I do recall Helicomparitor telling us why de-ice was not necessary, back when the French were not planning to install it. I think I heard that the 225 was now installing such a kit, as part of its need to meet the market that has been redefined.
Morning Nick
In fairness to HC, the 225/725 does have a certified blade deice system (it was developed initially for the military combat SAR 725 variant) and the French have reasonable blade deice experience with the AS332L system, which does work. The decision whether to equip the 225 with blade deice for North Sea operations, instead of using the limited icing clearance, has basically (and unfortunately) become a commercial one, weighing the number of days potentially lost due to icing (say a week or two per year maximum) against the lost payload from the weight of the system (around 2.5 passengers) for the other 50 or 51 weeks of the year. Your protege, of course, comes only with a full icing clearance and we just take the weight hit, but then (I think) we are safer in the winter because we aren't always worried about the 500 feet of positive air and whether or not the freezing level will come down in that shower we can't actually see too well on the radar. But that's my view.
In fairness to HC, the 225/725 does have a certified blade deice system (it was developed initially for the military combat SAR 725 variant) and the French have reasonable blade deice experience with the AS332L system, which does work. The decision whether to equip the 225 with blade deice for North Sea operations, instead of using the limited icing clearance, has basically (and unfortunately) become a commercial one, weighing the number of days potentially lost due to icing (say a week or two per year maximum) against the lost payload from the weight of the system (around 2.5 passengers) for the other 50 or 51 weeks of the year. Your protege, of course, comes only with a full icing clearance and we just take the weight hit, but then (I think) we are safer in the winter because we aren't always worried about the 500 feet of positive air and whether or not the freezing level will come down in that shower we can't actually see too well on the radar. But that's my view.
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Yes, Steve, I have heard only favorable comments from the de-ice systems on the 332 family. I do believe (independant of any competitive differences between specific models) that de-ice is simply part of the necessary kit, regardless of the rationalizations about percentage of use.
I can't recall, but I think the floats are used very much less than .00001% or the time, for example!
I can't recall, but I think the floats are used very much less than .00001% or the time, for example!
Steve, thanks for the offer but I am not around until after the 23rd when 212 has promised me a copy, so I think I will wait for that. From what you say it sounds as though there is quite a lot of "duplexity" in the system but are there any single failures that would cause a problem? I am thinking of a failed slip ring brush, open circuit on a blade heating element etc. And in fact a failure on just one blade would be really bad news owing to the out-of balance.
As I have said before, under some circumstances full deicing is not only safer but probably essential. However in the N Sea the conditions are such that we seem to cope safely without it. In my time (25 years now - old git!) I cannot remember seeing a single incident report, or hearing of anyone getting into significant trouble due to icing. No-flying days yes - a few each year of course, but that is not a safety issue.
By contrast Nick, the floatation system has been required a few times!
Given the choice, from a personal viewpoint I would of course rather have the system, just as I would rather have any other toys you care to chuck in, to play with or to make life less stressful (ACAS, digital map, autohover, though perhaps not TAWS), but de-icing doesn't seem to make economical sense to our clients so we do quite happily without it.
When CHC Abz get their 92 into service (and perhaps when BHL do the same) it will be nice to have de-icing as standard, but on the other hand you lose the ability to carry 19 passengers with baggage and full fuel - life remains a balancing act between fuel and passengers, something which in 225 world has been banished.
HC
As I have said before, under some circumstances full deicing is not only safer but probably essential. However in the N Sea the conditions are such that we seem to cope safely without it. In my time (25 years now - old git!) I cannot remember seeing a single incident report, or hearing of anyone getting into significant trouble due to icing. No-flying days yes - a few each year of course, but that is not a safety issue.
By contrast Nick, the floatation system has been required a few times!
Given the choice, from a personal viewpoint I would of course rather have the system, just as I would rather have any other toys you care to chuck in, to play with or to make life less stressful (ACAS, digital map, autohover, though perhaps not TAWS), but de-icing doesn't seem to make economical sense to our clients so we do quite happily without it.
When CHC Abz get their 92 into service (and perhaps when BHL do the same) it will be nice to have de-icing as standard, but on the other hand you lose the ability to carry 19 passengers with baggage and full fuel - life remains a balancing act between fuel and passengers, something which in 225 world has been banished.
HC
Avoid imitations
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Now, let me see.....
Icing protection or an extra passenger? .....
Seeing that our senior passenger seems to believe that icing is a mere figment of pilots' imaginations, not a difficult decision for me, especially in view of last winter's cooler temperatures.
Our heli (not a '92) could certainly make use of a retrofit.
Icing protection or an extra passenger? .....
Seeing that our senior passenger seems to believe that icing is a mere figment of pilots' imaginations, not a difficult decision for me, especially in view of last winter's cooler temperatures.
Our heli (not a '92) could certainly make use of a retrofit.
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Helicomparitor has trouble with redundancy, but I will (again) help him. The slip rings are also redundant, and certified as such.
Why does one sell de-ice systems, in spite of Helicomparitor's firm belief otherwise? One makes helicopters that customers want to buy. Customers are those in back, HC (or should I say Nick), not those up front at Bristow with rationalizations instead.
Why does one sell de-ice systems, in spite of Helicomparitor's firm belief otherwise? One makes helicopters that customers want to buy. Customers are those in back, HC (or should I say Nick), not those up front at Bristow with rationalizations instead.
Nick, thanks for clearing up the slip rings thing. Could you say, then, that there are no single point failures (short of daft things like blades falling off etc) that would bring the system down? If so, that is commendable, not sure that I am convinced just yet....
Customers, as you say Nick, are those in the back. They charter our aircraft, they pay my salary and increasingly they decide what equipment they want to have in the helicopters that they are going to fly around in. When they say that they would like to have de-icing, we will be delighted to supply that for them but so far they neither they, nor we, have identified a justification for the cost and weight (I say again, within the context of the N Sea). It does not make business sense to spend a lot of money on a feature that is not wanted by our clients nor strictly necessary. That would make us uncompetitive in a very competitive market, and going bust does not do much for flight safety.
Ditto when they say they would like to be flown around in an S92, though so far they have not said that, but I expect one of them might one day.... No rationalisations going on, just commercial reality.
HC
Customers, as you say Nick, are those in the back. They charter our aircraft, they pay my salary and increasingly they decide what equipment they want to have in the helicopters that they are going to fly around in. When they say that they would like to have de-icing, we will be delighted to supply that for them but so far they neither they, nor we, have identified a justification for the cost and weight (I say again, within the context of the N Sea). It does not make business sense to spend a lot of money on a feature that is not wanted by our clients nor strictly necessary. That would make us uncompetitive in a very competitive market, and going bust does not do much for flight safety.
Ditto when they say they would like to be flown around in an S92, though so far they have not said that, but I expect one of them might one day.... No rationalisations going on, just commercial reality.
HC
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Keep on truckin'
Originally Posted by NickLappos
Also, the aircraft was shown to be able to maintain safe flight control after many minutes with it all turned off, as a last resort. I believe it was at least 15 minutes.