Flight limits in falling snow
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Al Gore is lauging all the way to the bank, helped mightily by the mightily pathetic platitudes of the 'so called' politically correct who have a habit of spilling their guts in disarray all over the place.
His theories however were soundly debunked by a teenage schoolgirl a couple of years back, who surprisingly didn't get much press about it. I have the article somewhere.
The polar icecap this year has heaps of ice on it, so much that one hairy armpit mob changed the amount on their website at midnight one dark night recently, but, they got sprung didn't they. They had lopped off 500,000 sq kilometres.
His theories however were soundly debunked by a teenage schoolgirl a couple of years back, who surprisingly didn't get much press about it. I have the article somewhere.
The polar icecap this year has heaps of ice on it, so much that one hairy armpit mob changed the amount on their website at midnight one dark night recently, but, they got sprung didn't they. They had lopped off 500,000 sq kilometres.
Avoid imitations
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The RAF Puma HC1 had a limit (IIRC) of 20 minutes in blowing or falling snow.
Prior to the fitting of polyvalent intakes, snow would accumulate on the fairing between the engine intakes in forward flight. When it slid off, it would go sideways into one of the intakes and had the potential to cause a flameout.
Prior to the fitting of polyvalent intakes, snow would accumulate on the fairing between the engine intakes in forward flight. When it slid off, it would go sideways into one of the intakes and had the potential to cause a flameout.
TET - I'm with you on this one - the 'global warmers' data about Antarctica was misleading at best and downright dishonest at worst. The only area where ice is reducing in the whole of Antarctica is on the ice shelf that they concentrate exclusively on, conveniently ignoring the remaining 80% of the continent where the ice is increasing.
Another 'inconvenient truth' is that the earth was warmer in the Middle Ages than it is now so they chopped that data off their temperature graphs giving the 'hockey stick' display that appears to show a steady increase in global temperatures.
Strangely the term 'global warming' has lost favour and is now being replaced by 'climate change' by the scaremongers - it's still cobblers though
Another 'inconvenient truth' is that the earth was warmer in the Middle Ages than it is now so they chopped that data off their temperature graphs giving the 'hockey stick' display that appears to show a steady increase in global temperatures.
Strangely the term 'global warming' has lost favour and is now being replaced by 'climate change' by the scaremongers - it's still cobblers though
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Flying in snow
Just put my 44 away after a very nice local jolly in the snow. 5 inches on the ground and light snow falling.
I have never done it before so took the precaution of hovering a few inches off the pad just to see what I might expect on the approach.
No drama, lots of fun despite a backbreaking hour shovelling snow first.
Well worth the effort - the scenery was just stunning.
JB
I have never done it before so took the precaution of hovering a few inches off the pad just to see what I might expect on the approach.
No drama, lots of fun despite a backbreaking hour shovelling snow first.
Well worth the effort - the scenery was just stunning.
JB
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Albatross, that is just an awsome reality based picture. I myself have done much the same albeit in different machines. Oh the challenges of VFR winter work! If that was you, nice job.
Fly Safe
BWB
Fly Safe
BWB
Not me but it sure is a nice job by someone.
I think it is an Alpine Helicopters 212 on a Heli-Ski contract in Western Canada. Those guys know their way around the mountains and snow is practicaly required in the SOP I think. True professionals!
I can't remember who sent me the photo but it truely is a beautiful shot. The size was reduced for posting the full sized original is a work of art.
I think it is an Alpine Helicopters 212 on a Heli-Ski contract in Western Canada. Those guys know their way around the mountains and snow is practicaly required in the SOP I think. True professionals!
I can't remember who sent me the photo but it truely is a beautiful shot. The size was reduced for posting the full sized original is a work of art.
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I fly the AS350B3 with the sand filter and there is no limit in falling snow. I also fly the EC120 and the RFM says to avoid prolonged hovering in recirculating snow. The 120 has the barrier filter. Ive done the prolonged hovering thing and didnt have any issues. 
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Hi Albatross, well I could have sworn I'd read about the 212/412 falling snow limitation but now for the life of me can't find it so I must be confused with another type
. It would make sense that the Particle separators would do the job.
Anybody else remember anything about engine inlet snow deflectors for 212/412?
. It would make sense that the Particle separators would do the job.Anybody else remember anything about engine inlet snow deflectors for 212/412?
James Bay Daze:
Bell 47 with blade ice from flight of 2-3 minutes Ice fog -
206's A + B - with particle separator needs snow deflectors.
206's A + B - with no particle separator needs reverse scoops.
206 L (C-20B)- particle separator had to be removed and reverse scoops installed.
I recall at least 2 206s with no particle separator and no scoops flaming out in heavy snow.
( No not me )
205 - damned if I remember exactly - no scoops or deflectors - can't remember about anti-ice but we used to fly around in some very reduced vis in snow with no adverse effect however.
212 no scoops, no deflectors, no worry - durn things do not have inlet anti-icing - gotta love P+W - snow didn't hack the 90 deg turn down into the intake.
AS 350D carry on as normal
AS 350B I recall we had particle separators all year.
AS 355 straight intakes no Particle Separator - I think there was a limit if you had a particle separator installed but only flew TwinStars with particle separators installed in Africa where it did not snow much.
Long ago and far away now but that's how I recall the scenario.
Bell 47 with blade ice from flight of 2-3 minutes Ice fog -
206's A + B - with particle separator needs snow deflectors.
206's A + B - with no particle separator needs reverse scoops.
206 L (C-20B)- particle separator had to be removed and reverse scoops installed.
I recall at least 2 206s with no particle separator and no scoops flaming out in heavy snow.
( No not me ) 205 - damned if I remember exactly - no scoops or deflectors - can't remember about anti-ice but we used to fly around in some very reduced vis in snow with no adverse effect however.
212 no scoops, no deflectors, no worry - durn things do not have inlet anti-icing - gotta love P+W - snow didn't hack the 90 deg turn down into the intake.
AS 350D carry on as normal
AS 350B I recall we had particle separators all year.
AS 355 straight intakes no Particle Separator - I think there was a limit if you had a particle separator installed but only flew TwinStars with particle separators installed in Africa where it did not snow much.
Long ago and far away now but that's how I recall the scenario.
Last edited by albatross; 6th Feb 2009 at 08:21.
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The prevelance of snow generally precludes icing, since the two are opposites on how water is suspended in the air - supercooled ice cannot be snow.
The reason for snow limits on helicopters is almost always the threat that gobs of snow afford to the engine's air supply or inlets. The typical problem is with plenum fed engines, were the inlet is typically a hole or slot in a cowling, and the engine is inside somewhere, with its heated bell mouth far away from the initial opening. The deep pockets invite snow to collect where it can be partially warmed and then slog its way into the inlet.
Cures for snow ingestion usually involve shields or diverters that keep snow from forming near the plenum, or heating sections where the snow does for to melt it before it builds up. Flying a helo into snow when it is not approved is a very effective noise abatement scheme, once the engine(s) have quit.
Engines with exposed bell mouths or with heated inlet assemblies are virtually always immune to snow problems, since the ice tests for which the inlets are designed are far worse in heat requirements than the typical wet, heavy snow.
OT personal attack on crab@ deleted.
Senior Pilot
Rotorheads Moderator
Ramen,
I would suggest current science technology lacks the ability to accurately measure and quantify all of the data necessary to produce a scientific model that accurately forecasts future results as is required by scientific procedures for a model to be considered valid.
Even the IPCC in their Fourth Assessment (Section 8) point that out and call for more work to be done.
http://www.ipcc.ch/pdf/technical-pap...w/chapter8.pdf
Knowing Al Gore's amazing ability to conjure who images of grandeur for himself....as in claiming to have invented the Internet surely poses credibility problems for the man. Just as he relies upon James Hansen who works at the Goddard Institute of Space Studies (GISS) run by NASA. Hansen has been caught out using erroneous and false data in his models and has spurned the use of space based technology in his studies. That alone is an odd situation for NASA funded scientific studies. Is it the Satellite based sensors produce data that is contrary to his theories?
His models fail to accurately future temperatures which alone are enough to invalidate them based upon accepted scientific standards. Has any of his studies been given a legitimate Peer Review? Any of them? Just one even?
I do believe you are falling into the description of Warming Advocates that Roger Pielke, Jr. wrote of in his book "Honest Broker".
I would suggest current science technology lacks the ability to accurately measure and quantify all of the data necessary to produce a scientific model that accurately forecasts future results as is required by scientific procedures for a model to be considered valid.
Even the IPCC in their Fourth Assessment (Section 8) point that out and call for more work to be done.
http://www.ipcc.ch/pdf/technical-pap...w/chapter8.pdf
Knowing Al Gore's amazing ability to conjure who images of grandeur for himself....as in claiming to have invented the Internet surely poses credibility problems for the man. Just as he relies upon James Hansen who works at the Goddard Institute of Space Studies (GISS) run by NASA. Hansen has been caught out using erroneous and false data in his models and has spurned the use of space based technology in his studies. That alone is an odd situation for NASA funded scientific studies. Is it the Satellite based sensors produce data that is contrary to his theories?
His models fail to accurately future temperatures which alone are enough to invalidate them based upon accepted scientific standards. Has any of his studies been given a legitimate Peer Review? Any of them? Just one even?
I do believe you are falling into the description of Warming Advocates that Roger Pielke, Jr. wrote of in his book "Honest Broker".
Last edited by SASless; 7th Feb 2009 at 21:20.
Ten thousand years of 'nice weather' - Ice forcast !
Chief Bottle Washer
That's quite enough thread drift into global warming/cooling/climate change/Al Gore/etc. Nothing to do with Rotorheads, nor with "Flight limits in falling snow"
Unless you want this thread consigned to the doom and gloom of JetBlast?
Unless you want this thread consigned to the doom and gloom of JetBlast?
Ramen noodles - sorry to have missed your comments on me, I'm sure they were very informed and erudite - a bit like your knowledge of snow.
Snow can only form when there is an adequate supply of moisture (water vapour) that can condense into a water droplet and then freeze. The more water vapour there is, the bigger the snowflakes but there must also be freezing nuclei for the process to work. In the absence of the freezing nuclei, supercooled water droplets are formed and it is quite reasonable to have both SCD and snow, especially in the cloud from which the snow is falling.
Many icing limitations (ours included) specifically prohibit entry into cloud when it is snowing for exactly this reason.
At the moment in the UK much of the weather is mixed rain and snow (sleet in old money) falling from the same clouds so how can they be mutually exclusive?
BTW what exactly is supercooled ice?
Snow can only form when there is an adequate supply of moisture (water vapour) that can condense into a water droplet and then freeze. The more water vapour there is, the bigger the snowflakes but there must also be freezing nuclei for the process to work. In the absence of the freezing nuclei, supercooled water droplets are formed and it is quite reasonable to have both SCD and snow, especially in the cloud from which the snow is falling.
Many icing limitations (ours included) specifically prohibit entry into cloud when it is snowing for exactly this reason.
At the moment in the UK much of the weather is mixed rain and snow (sleet in old money) falling from the same clouds so how can they be mutually exclusive?
BTW what exactly is supercooled ice?
Many icing limitations (ours included) specifically prohibit entry into cloud when it is snowing for exactly this reason.
You can enter a cloud in freezing conditions but may or may not get icing on the helicopter, you will never know about the ice until you are inside the cloud.
As I understand you need to avoid that 'below 0C' cloud as far as possible or enter it only if you have enough altitude below in case you encounter icing.
regards
Aser
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crab,
The removed sections dealt with your introduction of politics to this thread, and they were (rightly) removed by Senior Pilot as being a bit too rough.
The simple fact is that in many of hours of snow and icing flight, and in the qualification of several helos in snow (the reason why I entered this thread, having experienced at least one engine failure in a prototype due to snow ingestion), I have never seen Ice where there is snow. And BTW, sleet is not snow, unless you decided to change the definition. The boundary between the two forms of precip is usually a temperature change, in my experience, where the temp goes close to zero C and sleet/freezing rain are present. Once moisture makes snow, it does not make ice. The change from sleet to snow can take place in as little as 5 miles of airspace, but I repeat, where there is snow, there is not ice.
Supercooled ice comes in Bourbon, btw.
acer, I certainly agree with you. "Known" would seem to allow one to fly in clouds where no reports of ice exist, but that is a sucker hole. In terms of flight planning, cold clouds mean the reasonable probability of "knowing" there will be ice, period. The cure is simple. Get a helo with blade anti-ice!
However, flight in snow virtually never results in icing, unless the temperature is nearer freezing where you can cross the line between snow and sleet/freezing rain.
The removed sections dealt with your introduction of politics to this thread, and they were (rightly) removed by Senior Pilot as being a bit too rough.
The simple fact is that in many of hours of snow and icing flight, and in the qualification of several helos in snow (the reason why I entered this thread, having experienced at least one engine failure in a prototype due to snow ingestion), I have never seen Ice where there is snow. And BTW, sleet is not snow, unless you decided to change the definition. The boundary between the two forms of precip is usually a temperature change, in my experience, where the temp goes close to zero C and sleet/freezing rain are present. Once moisture makes snow, it does not make ice. The change from sleet to snow can take place in as little as 5 miles of airspace, but I repeat, where there is snow, there is not ice.
Supercooled ice comes in Bourbon, btw.
acer, I certainly agree with you. "Known" would seem to allow one to fly in clouds where no reports of ice exist, but that is a sucker hole. In terms of flight planning, cold clouds mean the reasonable probability of "knowing" there will be ice, period. The cure is simple. Get a helo with blade anti-ice!
However, flight in snow virtually never results in icing, unless the temperature is nearer freezing where you can cross the line between snow and sleet/freezing rain.
Ramen - snow is an ice crystal so the SCD can evaporate onto the freezing nuclei (Bergeron-Findeisen process) or freeze on impact with a cold airframe. Equally the snowflakes can melt as they fall and again freeze on contact with a cold airframe.
Blade anti-ice only protects the blades and will not protect the rest of the airframe from SCD.
Blade anti-ice only protects the blades and will not protect the rest of the airframe from SCD.