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What are 'Icing Conditions'?

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What are 'Icing Conditions'?

Old 18th Feb 2010, 22:50
  #41 (permalink)  
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HC - my answer would be that you can't because there is no specific clearance to say you can
In the EC225 flight manual it doesn't mention that its OK to do a spot turn. Does that mean I can't do one?

Look in the RFM.
Good suggestion! But whilst the main part of the RFM says "flight in icing conditions prohibited", there is a Supplement that allow flight in limited icing conditions with specified equipment and caveats, however it doesn't say that flight in freezing precipitation is prohibited.

JohnDixon - it would be nice if the RFM covered this point but it doesn't...

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Old 18th Feb 2010, 23:58
  #42 (permalink)  

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I would class freezing precipitation as icing conditions (the worst sort).
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Old 19th Feb 2010, 07:49
  #43 (permalink)  
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HC - then you start to get into a rather fatuous argument like - does it say you can't fly backwards at 50kts? no, therefore it must be OK.

Spot turns are hardly a well documented, hazardous regime of flight (aklthough with some students I have had that might not be so) whereas flight in FP is. If your pilots want to go and fly in FP, let them and see what their viewpoint is when (if) they get back.

At some point you either have to force the manufacturer to amplify the limits in the RFM or, as you have done, make a clear policy decision not to fly in FP.
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Old 19th Feb 2010, 18:35
  #44 (permalink)  
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Isn't Freezing precip an icing condition?

HC and ShyTorque, A few years ago the FAA legal chaps wrote a response to the AOPA on this subject and in essence, referred them to the AIM, paragraph 7-1-22 and 23.

Not the clearest prose, but thats probably the best practical approach, because if one wants a complete technical definition, including liquid water content and droplet size, one would be asking for info not available in any met office briefing.

John Dixson
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Old 19th Feb 2010, 20:02
  #45 (permalink)  

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Thanks John for the reference but I'm not familiar with the term "AIM" or where to find it.
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Old 19th Feb 2010, 20:16
  #46 (permalink)  
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Shy, you can find it here

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Old 19th Feb 2010, 21:43
  #47 (permalink)  

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Please accept my sincere graticule.
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Old 19th Feb 2010, 22:30
  #48 (permalink)  
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I posted some photos of flight in known icing conditions,that were taken between 1969-73,in Canada,in Sea-king,Wessex,Wasp and Gazelle icing trials.They`re on P 15 of `R/heads around the World,28 Nov `03. Trials were done in stratiform sub-0 cloud,with a good cloudbase,and heavily instrumented aircraft.

A Gazelle we did icing-trials with in Ottawa, 1976 Feb-Mar. We flew in everything from heavy snow to freezing rain, Spray-rig, and freezing fog. I see from my log book that I also spent most of the time with the hyd. off for control force measurements.

Ice-damage to a Wx/S-K engine(T-58/Gnome), which also illustrates why an axial-flow compressor with VIGV`s is not an ideal engine to use in a helo, without adequate intake protection.

A WX blade with ice :we used a max rise in Tq. of about 20-25 %, before you quit, IF you were not getting ice shedding naturally. That would still give you an acceptable rotor performance if both motors quit/or a trans. failure. Which did happen in a S-King-- Everyone had their chutes on, but they got back before the g/b seized.

AH-56A Cheyenne on an early rig-run.

Front shot of a Wasp blade, showing the stagnation-point at the L/E, and ice growing out above/below the blade; very dangerous as the rise in drag/ torque is very rapid.

Last edited by Senior Pilot; 20th Feb 2010 at 02:18. Reason: Photos added
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Old 20th Feb 2010, 12:04
  #49 (permalink)  
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Thanks very much for the pix. Great contribution! Send more.
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Old 28th Mar 2010, 10:59
  #50 (permalink)  
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What are 'Icing Conditions'?

Aircraft Icing Training - Courses

All of your questions regarding icing are answered in the above link. Its a fantastic resource and its completely free. In short, if the SAT is between +2 and -20c and there is visible moisture in the atmosphere, then an airframe can accrete icing. The only limiting factor on the cold side is -40c. From a legal standpoint what are known icing conditions.? Well if you fly into visible moisture below the forecast freezing level, ie cloud, FZFG, FZRA, supercooled large droplets, ice pellets etc and your in a non de-iced aircraft and an accident results. The likely candidate who will inform you of the legalities would more than likely be your insurance company if you survive of course. Its also right as whirly mentions that snow isnt considered as icing conditions in flight (explained in the course relating to temp at which snow exists) but snow on an aircraft on the ground is a different issue and certainly would be considered a danger as snow insulates and a layer of snow on the aircraft on the ground could leave the airframe covered in a coating of ice. Any snow/ice should be removed prior to flight. I have known some people who thought, ah the snow will blow off when I start to roll? It most certainly would but what it left behind would certainly diminish the aerodynamic properties of said aircraft and the POH figures could be severely out.
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Old 29th Mar 2010, 19:24
  #51 (permalink)  
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I'm looking for some information and informed experience on helicopter ice detection systems...

such as which ones are reliable, which ones aren't worth jack, how much warning they give you before the aerodynamic affects are noticeable.

Any info much appreciated.
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Old 29th Mar 2010, 21:50
  #52 (permalink)  
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What are 'Icing Conditions'?

YouTube - N1278L Icing Encounter.wmv

These are icing conditions and this is what happens when a full understanding of them arent met. And this aircraft was fully de-iced but a de iced aircraft in unskilled hands and the icing usually wins

Last edited by Senior Pilot; 29th Mar 2010 at 22:04. Reason: Embed YouTube link
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Old 10th Nov 2010, 03:58
  #53 (permalink)  
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Question ***** ICE *****

Hello fellow Rotorheads.

Winter as arrived here in Europe. Ice formation is an old problem, but it continues to kill.

I never had to face it and would like to keep it that way, but if I have to face it it's best be be better informed to solve or avoid it the best way.

The only indication the most RFM gives besides not get in to the condition is to turn on the PITOT at 5 C to 0C.
I can go through the clouds at temperaures very negative?

At what temperatures can not pass into the clouds. I've read the information from +5 C to 0 C and also have read from 0 C to -10 C. ..?

I wish that those who have some experience in the subject write here in the forum to better clarify this phenomenon, identification signs and solutions.

Thank you all in advance, and sorry about my English writing.

Safe Landings To All...
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Old 10th Nov 2010, 12:13
  #54 (permalink)  
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There are engine icing conditions and airframe icing conditions. It is possible to get engine intake icing on some types well above zero (depends a lot on the intake design.) Likewise on the pitots, because of the pressure drop in the airflow around them, causing a reduction in the temperature from ambient.

Airframe icing will tend to start at one particular place for each airframe. Often the first place you will see it is on the wipers, the front of skids or antennae. You will have to ask around for the acquired knowledge on your particular aircraft. Airframe icing builds up fastest in temperatures close to zero, because of the size of droplets and the time it takes them to freeze as they run over the airframe. You can build up ice very quickly if you are in the wrong conditions, affecting the performance of your rotors (main and tail), affecting balance, aircraft weight, ability to autorotate etc. Shedding of ice from the rotors can damege other parts of the aircraft. In very cold weather, you may get less icing, but its best not to try it!

If your rotorcraft flight manual says to avoid icing conditions, then the best plan is to do just that. Dont fly where icing conditions are forecast - especially freezing rain. If you do enter icing conditions, turn round and get out again.
I knew a colleague when I was in the Navy who flew a Sea King into icing conditions. There was no way out (in cloud in mountainous region, no radar). They ended up pulling maximum contingency power at best rate of climb speed, and were still descending fast. They were lucky enough to exit the cloud at the base without hitting the ground , but it could easily have gone the other way!
Most helicopters dont like icing - very few have significant airframe/rotor icing protection. If you dont want to scare yourself, stay out of the clouds in Winter!
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Old 10th Nov 2010, 15:40
  #55 (permalink)  
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Icing conditions occur when your Wife's mother catches you in the rack with her other daughter.
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Old 15th Nov 2010, 12:35
  #56 (permalink)  
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here you go guys, something Mrs tet found in

Watts Up With That?
one of the frequented blogs when we were fighting the warmists, also there is a substance the name of which totally eludes me now but it was around a few years ago for sure which you could spray on your motor car windscreen and it would disspate the rain drops very well allowing much less use of the wipers. If I can remember it I'll post the name.

cheers tet

Fighting ice at the nano level a promise for improved safety

Posted on November 14, 2010 by Anthony Watts
This is a really neat discovery. As we all know, ice is a big killer and safety hazard, especially on airplanes. This new material prevents supercooled droplets from freezing, sticking, and accumulating.- Anthony

From Harvard: Breaking the ice before it begins
Nanostructured materials repel water droplets before they have a chance to freeze
Sequential images of ice layer removal from hydrophilic Al, fluorinated hydrophobic Si, and microstructured fluorinated Si (SHS). Note the supercooled droplet bounces right off without sticking.

Cambridge, Mass., November 12, 2010 Engineers from Harvard University have designed and demonstrated ice-free nanostructured materials that literally repel water droplets before they even have the chance to freeze.
The finding, reported online in ACS Nano on November 9th, could lead to a new way to keep airplane wings, buildings, powerlines, and even entire highways free of ice during the worst winter weather. Moreover, integrating anti-ice technology right into a material is more efficient and sustainable than conventional solutions like chemical sprays, salt, and heating.
Continue reading →

Posted in Science, Technology, weather | 49 Comments
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Old 16th Nov 2010, 03:07
  #57 (permalink)  
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Do you mean Rain X ?

That aeroplane looks scary. I can't believe it is still generating lift with all of that on.
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Old 19th Nov 2010, 11:41
  #58 (permalink)  
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Do you mean Rain X ?
yes I think so.
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Old 28th Nov 2010, 23:31
  #59 (permalink)  
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AIC 118/2006 (Pink 106) 5.1

This AIC will give you the CAA definition of Freezing +3C < 1500m Viz.

I hope it helps.
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Old 29th Nov 2010, 02:12
  #60 (permalink)  
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Come to Canada, if you can;t figure icing conditions this time of year, theres no hope......been in it all day, on a longline, you start picking up ice, you land, wait 10 mins, then go again when it clears up....easy...Still got 6.2 in and thats 8hrs of daylight.....
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