Why no ice?

Discussion in 'Cleared for the Approach' started by Mtns2Skies, Dec 17, 2016.

  1. Mtns2Skies

    Mtns2Skies Pattern Altitude PoA Supporter

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    I was flying right seat with a buddy with his instrument. We flew from BJC (Denver Area) to BFF(Scottsbluff) for some food in a 182RG with a STOL kit. Visibility was maybe 1/2 miles to maybe a mile of vis for about .8 of the trip and the OAT was about 23F. Why the heck didn't we pick up ice?
     
  2. kgruber

    kgruber En-Route

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    Ice is where you find it. Very often, flying in cloud......below the freezing level.....there might be no ice.
     
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  3. frfly172

    frfly172 Touchdown! Greaser!

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    Not enough moisture in the air you where flying in.
     
  4. Mtns2Skies

    Mtns2Skies Pattern Altitude PoA Supporter

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    Even though it was visible moisture?
     
  5. Ryanb

    Ryanb En-Route PoA Supporter

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    I would say that any visible moisture might have already been frozen which would've made it too cold to stick onto the airframe, but 23F or -5C most likely wouldn't do it. Under the conditions you described it seems as though icing would be likely. Interested to hear others' opinions on this.
     
  6. Zeldman

    Zeldman En-Route

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    What caused the 1/2 mile visibility...snow, fog, mist....?
     
  7. Clark1961

    Clark1961 Touchdown! Greaser!

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    The moisture was glaciated and had warmed to 23. This is a large arctic air mass...

    Also remember that air warms coming down off the Rockies
     
    Last edited: Dec 17, 2016
  8. Mtns2Skies

    Mtns2Skies Pattern Altitude PoA Supporter

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    On the way there fog/cloud, on the way back snow.
     
  9. Ryanb

    Ryanb En-Route PoA Supporter

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    I'm not familiar with the area nor the current conditions. I was just basing that off of the OAT alone. Typically getting into -30 range, give or take, freezes any moisture in the air, reducing the the chances for anything to stick.
     
  10. kgruber

    kgruber En-Route

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    You are unlikely to get ice when it is snowing.
     
  11. RotorDude

    RotorDude Pattern Altitude

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    In my experience you pick up icing less than 50% of the times you might expect it, sometimes much less. Airframe icing forms when you have "supercooled" water droplets that hit your airframe. That means those droplets must be: a) below zero degrees C; and b) still liquid!
    You might wonder how water can remain liquid below the freezing temperature, but that's actually very normal. Sufficiently cold water only freezes when it has something that shakes it a bit, and hitting your airplane does just that, at which point the droplet instantly freezes and adheres to the surface that shook it.
    Having those supercooled water droplets hang around waiting for you to pass through is not all that common. Very often they are already frozen by the time you get there, so no (d)ice. (Already frozen ice/snow particles will bounce right off.)
    Once you understand all this, you'd be much better equipped to fly safely through areas that are theoretically conducive to icing, and get your backside safely out of icing conditions when inadvertently encountered.
     
    Last edited: Dec 17, 2016
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  12. tlglenn

    tlglenn Line Up and Wait

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    I remember this one time being vectored to an Austin airport through hard IMC. The outside air temperature was around 0C. I was flying a 182. The controller was working another 182 at the same altitude that was reporting ice. I had nothing which I reported.
     
  13. l8evator

    l8evator Pre-takeoff checklist

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    So how was the food and service at Scottsbluff? The airport restaurant seems to go through operators frequently. It's a nice facility but traffic might be too low to support it.
     
  14. Mtns2Skies

    Mtns2Skies Pattern Altitude PoA Supporter

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    Fantastic service, food though looked promising was a bit disappointing overall. My fried chicken was undercooked and my buddy's burger was dry. But it was still a cool place.
     
  15. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Does a skew-T help with this question?
     
  16. RotorDude

    RotorDude Pattern Altitude

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    Absolutely. It's my number one defensive weapon, coupled with this tool, which is very likely based on skew-T data. You generally want to avoid the areas of expected icing (esp. in non-FIKI), which skew-T does a good job of predicting. As far as the age of the droplets (old cold droplets tend to freeze and become less of a hazard), you can only guess, but logically the colder the droplets the sooner they freeze.
     
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  17. Tom-D

    Tom-D Taxi to Parking

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    Visible moisture can be frozen, and won't stick to a super cooled surface.
     
  18. Clark1961

    Clark1961 Touchdown! Greaser!

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    That's really the thing about ice, you have to know the airmass and what it's been through.
     
  19. jordane93

    jordane93 Final Approach PoA Supporter

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    Luckily nothing stuck. Flying into icing conditions in a non FIKI plane is not my idea of fun.
     
  20. Jim Case

    Jim Case Pre-takeoff checklist

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    Likely because the moisture you saw was already frozen. And thus didn't stick to the frame of the airplane. It's definitely interesting though, under the conditions described, it seems like icing would be nearly unavoidable. I'm sure someone will break it down more, and give a more detailed if not better all a
     
  21. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Lets see it then, for the place and time in the o.p.
    Someone show us why or how he could have known in advance.
     
  22. RotorDude

    RotorDude Pattern Altitude

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    The only way "icing would be nearly unavoidable" is if you had supercooled liquid water droplets sitting around and waiting for you. In many situations they are either already frozen, or not cold enough.
    The OP's 23F OAT (-5C) is certainly in the "danger zone", but the droplets encountered could have already been frozen when the aircraft met them, at which point they'd bounce right off.
    As I mentioned above, in my experience very often the droplets you meet are frozen, so there is no icing, therefore this case wouldn't be at all surprising.
    It's also possible the droplets were liquid but very small, which would have required a very long time to get an appreciable buildup.
     
  23. Ryanb

    Ryanb En-Route PoA Supporter

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    Jim,
    What you wrote above is nearly the exact same as what I said, almost word for word too, you just re-stated it. Did you really just come up with the same idea that I had?! :dunno:
     
    Last edited: Dec 18, 2016
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  24. Art VanDelay

    Art VanDelay Pattern Altitude

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    It's pretty tough to get any light airplane actual IMC in the Denver area. On the rare occasions when they get that kind of weather it can quickly exceed the abilities of most GA aircraft.
     
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  25. Cpt_Kirk

    Cpt_Kirk En-Route

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    I've been IMC @ 0*c in a few types. No ice. It happens.
     
  26. mondtster

    mondtster Cleared for Takeoff

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    Ice can be strange. Just the other day I was getting vectored for an approach and while I was east of town there was no ice, but north and west of town I started to pick up some light ice. I was in IMC the whole time, and there was a guy who just gave a pilot report of negative ice right before I showed up in the same area he was at when he reported. So in your situation, it is conceivable that at his location there was ice but not in your location.

    The conditions may have been conducive to ice, but the OP never mentioned anything of flying in known ice conditions. It might be a minor nit to pick but there is a difference. ;)
     
  27. Jim Case

    Jim Case Pre-takeoff checklist

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    Seems like it. Any other explanation as to why that would happen?
     
  28. Jim Case

    Jim Case Pre-takeoff checklist

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    This is what I meant by a "more detailed explanation" . I was simply referring to icing being highly likely in this senerio.
     
  29. Ryanb

    Ryanb En-Route PoA Supporter

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    I find that hard to believe Jim. Now I feel like you're just trolling. o_O
     
  30. comanchepilot

    comanchepilot En-Route

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    So the airframe is below freezing and the air hitting it is below freezing - and the moisture is below freezing- its gonna stick how?

    I've usually only seen ice in convective clouds [cumulus] in the top 1000 feet or so - and then again in freezing rain in a layer in the clear - which makes a helluva lot of sense.
     
  31. Jim Case

    Jim Case Pre-takeoff checklist

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    I could care less what you believe. I don't know what trolling is but believe me, I don't really have enough spare time to waste arguing with you, you are going on the ignore list.
     
  32. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    That's the ONLY place you've seen ice? Really???
     
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  33. comanchepilot

    comanchepilot En-Route

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    other than thats not what I said -

    on an airplane in the air . . . . sure

    I've seen ice in my drink, I've put in a margarita machine, I see it on the mountains - but I never see it on the ground anymore . . .
     
  34. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    Me thinks you must not have spent much time in the clouds in cold weather then. I've picked up ice in many non convective cloud layers.
     
  35. comanchepilot

    comanchepilot En-Route

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    c.mon - what I said was the "I've usually only seen ice. . . . ' I never said only or never- words mean things. All of them.

    You're running into ice alot in non-convective winter stratus - maybe launching into those conditions in a non-FIKI airplane requires a different decision tree. . .
     
  36. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    Still it's an odd thing to say 'usually' about.

    At any rate, maybe I misinterpreted your original post, but it seemed you were implying that as long as you were busting around in stratus laters, you'd be fine, which is contrary to my ice experience.
     
  37. gkainz

    gkainz Final Approach PoA Supporter

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    You must have been flying Spirit - ice is now extra charge
     
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  38. denverpilot

    denverpilot Taxi to Parking

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    I think that's the first time I've ever heard "cool" and "Scottsbluff" in the same sentence. :)

    Sometimes air masses come with all sorts of emotional baggage. ;)
     
  39. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    I did not see anyone post this (the plot for the time and place in question and a description of how it works). Starting to doubt that it can predict as described. Surely plot history is available?
     
  40. coloradobluesky

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    Its the same as in your car. Some snowstorms, sleet storms and rainstorms produce ice and some don't. The odd thing about icing to remember is you CAN get ice when the temperature is ABOVE 32 degrees, maybe as high as 38 degrees F or even higher. This is due to the existence of water that is below 32 degrees but hasnt turned to ice. This water floats around in the air, and the air it is in can be at a higher temp than freezing, which seems kind of odd. When the airplane collides with the water it turns into ice. This phenomenon is called "supercooled droplets of water". Most of us learned that when water goes below 32F it turns to ice. Turns out it CAN stay liquid down to quite a bit below 32F. Interesting phenomenon. When an airplane runs into an area of supercooled drops of water, the leading edges of the airplane and the windshield all get covered with ice. Not nice.

    There are two kinds of ice. Clear ice and rime. Clear ice is not always perfectly clear, it can be white. It is white from air trapped inside the ice. Clear ice can be smooth or knarly surfaced. There is also "mixed ice", which is a combination of clear and rime. Rime is more like frost. If you get ice and report it to ATC they will want to know the outside temperature and the type of ice.
     
    Last edited: Dec 27, 2016