Icing at -38c

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Bravo

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Bravo
I just transitioned into an SR22 with FIKI and during my transition training was able to experience icing for the first time. I remember hearing that +2c to -20c was the spread to be cautious when flying non-fiki. Maybe I misread something?anyhow, we were flying along at 8k and started picking up rime ice and it didn't stop until getting above the clouds at 12k. Nothing the Cirrus couldn't handle well, but I was surprised to see it at that temp. Just thought I would pass it along to keep everyone safe.
 
The FAA now says turn on anti icing equipment below +10C and in visible moisture.
Obviously one would assume that at -20 or so any moisture would already be frozen, but there is probably a reason they left it so open ended like that. Covers their bases at least.
 
Bravo said:
I just transitioned into an SR22 with FIKI and during my transition training was able to experience icing for the first time. I remember hearing that +2c to -20c was the spread to be cautious when flying non-fiki. Maybe I misread something?anyhow, we were flying along at 8k and started picking up rime ice and it didn't stop until getting above the clouds at 12k. Nothing the Cirrus couldn't handle well, but I was surprised to see it at that temp. Just thought I would pass it along to keep everyone safe.
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What was "that temp"?
 
:eek:

Holy crap that is cold. Was the cabin heat keeping up?
 
RotorDude said:
Same temp for 4000'? doubtful, as well as -38c at 12,000' near MD.
Not a very good icing Pirep, I'm afraid.
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Considering was -15C a few days this week, I do believe the -38 at 12,000. It has been horrible here this past week. Moving to Florida is looking better and better.
 
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If I recall correctly, a B-52 picked up ice at -40 degrees. I'm sure that you have seen SLD (semi-liquid droplets) in icing discussions. Although as terrestrials we think of 32F as the freezing point, water in liquid form exists afar below zero at high altitude; all it takes is a disturbance, like a passing wing, to change state from liquid to solid. See if you can find a copy of "The Weather Book" by USA Today weather editor Jack Williams (copyright 1992)...he has a great section on icing.

Bob Gardner
 
-38C at 12,000 feet? Where? The only place I'm seeing a temperature that cold at that altitude today is over Hudson Bay in northern Canada. If you were in Maryland, it wasn't even down to -10C at that altitude today, although the temps there would certainly have been in the heart of the icing envelope. You might want to check your OAT gauge.
 
Ron Levy said:
-38C at 12,000 feet? Where? The only place I'm seeing a temperature that cold at that altitude today is over Hudson Bay in northern Canada. If you were in Maryland, it wasn't even down to -10C at that altitude today, although the temps there would certainly have been in the heart of the icing envelope. You might want to check your OAT gauge.
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It wasn't today. It was Thursday evening. Heck, it was -14F at my house that evening Ron. You do remember where I live right?

Edit.. I just remembered I took a picture with my phone of the temp right after we started climbing out of 8k to get out of the ice.
 

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Something to keep in mind is that the minimum temp for the FIKI system to work according to my POH is -34 C.
 
PFD in that photo shows -32 C for the OAT. That is -26 F. Pretty cold, but very believable.

Are you sure you didn't pick up the ice at another altitude where it was warmer?
 
On the way in to KHPN White Plains NY 2 days ago we had temp of -42 at 15,000 feet. We both noted that we have never seen it that low before at that low of a ALT.

So I'm thinking it is very possible

Steel
 
Might be -24C at the surface projected to -38C at 8000 - but - and this is a huge butt - you'd see an inversion leading to temps much warmer at altitude. Which is where the Skew-T comes in handy.

I took off on a 6F am in Connecticut one December AM and by the time I got to 8500 in severe clear over the CT river it was 32F . . . . explains the severe clear too.
 
Wingsofglass said:
Something to keep in mind is that the minimum temp for the FIKI system to work according to my POH is -34 C.
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I will have to see if it says that. Didn't even think of that.


NoHeat said:
PFD in that photo shows -32 C for the OAT. That is -26 F. Pretty cold, but very believable.

Are you sure you didn't pick up the ice at another altitude where it was warmer?
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We entered the clouds at 7500' and had icing which got worse as we got near the tops at approx 11000' with colder temps at -38C.
 
Bravo said:
It wasn't today. It was Thursday evening. Heck, it was -14F at my house that evening Ron. You do remember where I live right?

Edit.. I just remembered I took a picture with my phone of the temp right after we started climbing out of 8k to get out of the ice.
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-32C at 8500 (which is what I see in that picture) would be about ISA-30C, which is quite a bit non-standard, but not unthinkable if the surface temp is 14F (about -10C). However, with that surface temp, I'd still be expecting it a bit warmer than that, so I'm guessing you had an unusually steep lapse rate. That suggests some instability in the atmosphere, which increases the likelihood of supercooled droplets. In any event, it appears you found a combination of circumstances which resulted in the normally unlikely situation where icing occurred with temps in the -30's, so now you know that those temps are not a guarantee of no icing.
 
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Ron Levy said:
-32C at 8500 (which is what I see in that picture) would be about ISA-30C, which is quite a bit non-standard, but not unthinkable if the surface temp is 14F (about -10C). However, with that surface temp, I'd still be expecting it a bit warmer than that, so I'm guessing you had an unusually steep lapse rate. That suggests some instability in the atmosphere, which increases the likelihood of supercooled droplets. In any event, it appears you found a combination of circumstances with resulted in the normally unlikely situation where icing occurred with temps in the -30's, so now you know that those temps are not a guarantee of no icing.
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It was actually shocking to the instructor I was with as well. Btw. It was minus 14F at my house. :eek: +14 would have felt like a heat wave. :)
 
Wingsofglass said:
Something to keep in mind is that the minimum temp for the FIKI system to work according to my POH is -34 C.
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Just read where mine says -30F (-34C) , guess we broke that rule. Atleast we now know it works to -38C ;)
 
You're not supposed to use most boot systems below -35 F. You can damage them.
 
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