Icing Conditions

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fire67bird

Filing Flight Plan
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fire67bird
I’m working on my PPL and have my night flight coming up. I’m down in the south where the humidity is high and the forecast that day is calling for 30 F temperatures. Other than the humidity it’s supposed to be clear that night. I’m anticipating some carb icing which isn’t a problem with the carb heat. Is there potential for airframe icing in those conditions?
 
Airframe ice is a visible thing for the most part, so shy of IFR level visibility, or precip of some sort, I wouldn’t worry about it.
 
This might be a good time in your training to get familiar with FAA Advisory Circulars. https://www.faa.gov/regulations_policies/advisory_circulars/

They cover all kinds of topics of interest to pilots. As a student pilot you should read AC 00-6B Aviation Weather. There is a section in it that covers icing.

For icing to occur, the outside air temperature must be below 0 °C. As clouds get colder, SLWC decreases until only ice crystals remain. Thus, almost all icing tends to occur in the temperature interval between 0 °C and -20 °C, with about half of all reports occurring between -8 °C and -12 °C. In altitude terms, the peak of occurrence is near 10,000 feet, with approximately half of incidents occurring between 5,000 feet and 13,000 feet. The only physical cold limit to icing is at -40 °C because liquid droplets freeze without nuclei present.

If that interests you, then check out AC 91-74B Flight In Icing Conditions.
 
Airframe icing can only occur with visible moisture (ie., clouds, freezing rain etc). If that isn’t present than the odds of ice accumulation are next to nothing.

The question I would present to you would be, can you still fly when the ambient temperature is below freezing?
 
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Ryanb said:
Airframe icing can only occur with visible moisture (ie., clouds, freezing rain etc). If that isn’t present than the odds of ice accumulation are next to nothing.

The question I would present to you would be, can you still fly when the ambient temperature is below freezing?
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I appreciate the clarification. That is pretty much how I was interpreting it but wanted to get the experts verification.

As for flying when ambient temp is below freezing I figure there are airframe limitations based on temperature but am unaware of any FAA restrictions. If there are I would be grateful if you could point me in the right direction so I can read up on it.
 
Ryanb said:
Airframe icing can only occur with visible moisture (ie., clouds, freezing rain etc). If that isn’t present than the odds of ice accumulation are next to nothing.

The question I would present to you would be, can you still fly when the ambient temperature is below freezing?
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Why couldn’t you?

Would kinda destroy aviation in most of the north part of the US for most of the year.
 
Ryanb said:
Airframe icing can only occur with visible moisture (ie., clouds, freezing rain etc). If that isn’t present than the odds of ice accumulation are next to nothing.

The question I would present to you would be, can you still fly when the ambient temperature is below freezing?
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Are you implying they couldn’t fly at below freezing temps?
 
fire67bird said:
I’m working on my PPL and have my night flight coming up. I’m down in the south where the humidity is high and the forecast that day is calling for 30 F temperatures. Other than the humidity it’s supposed to be clear that night. I’m anticipating some carb icing which isn’t a problem with the carb heat. Is there potential for airframe icing in those conditions?
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No.

However, there is potential for frost to form on top of your wing while the plane is sitting outside after sunset, especially if the winds are calm. I would suggest preflighting in a hangar.
 
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