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Icing in thick altostratus at -2°C

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Star Alliance created the topic: Icing in thick altostratus at -2°C

Hi all, a quick question regarding icing:
You are cruising in thick altostratus cloud where the outside air temperature is -2°C. What type of icing is most likely to occur?
A.rime ice
B.clear ice
C.both rime and clear

I saw this question from previous post. I would go for C, because the word ”thick ” means strong vertical development which can form large droplet. But someone says the answer A)rime ice only is correct.
Can’t find a solid answer. Can anyone help?
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bobtait replied the topic: Icing in thick altostratus at -2°C

Clear ice would be correct. If that is one of my questions, can you let me know where you found it.

Bob
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Star Alliance replied the topic: Icing in thick altostratus at -2°C

Hi Bob,
Thanks for your reply! This question isn't from your book, maybe it's a feedback from CASA or practice exam.

In the booklet from BOM, it says "light to moderate rime ice , clear ice possible in lower level " . So why don't we go for both rime and clear ice?
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Star Alliance replied the topic: Icing in thick altostratus at -2°C

Sorry Bob, I find where it's from. It's on page311, reversion questions set 1 No.9. The answer you give is clear ice only. But some guys say rime and clear should be better.
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S70BlackHawk replied the topic: Icing in thick altostratus at -2°C

It’s B clear ice for two reasons. 1st is the cloud type. As you mention the “thick” vertical development and thus larger water droplets. 2nd is the temp is only -2deg. So not as cold for when the large droplets impact the aircraft.
Combination of these two factors lead to a large, not so cold 0 to -10deg, droplet hitting the leading edge and then sliding back and freezing. Thus causing clear ice. Rime is formed at much colder temps -10-20deg and smaller droplets in stratiform clouds because they freeze on impact. Causing clumps of ice with air trapped inside as well. Hope this helps.
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