NoPax said:
Airmet Zulu, isn't "known icing"...its an advisory that (upto moderate) icing has been forecast in sometimes a large geographical area. As a former poster said, if its in a PIREP, then it's "known".
This excerpt from a 1997 NTSB decision would appear to disagree with you.
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The Board has long viewed the phrase "known icing conditions" to include predicted weather: "We do not construe the adjective 'known' to mean that there must be a near-certainty that icing will occur, such as might be established by pilot reports....Rather, we take the entire phrase to mean that icing conditions are being reported or forecast in reports which are known to a pilot or of which he should be reasonably aware."
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http://www.ntsb.gov/O_n_O/docs/AVIATION/3870.PDF
In fact, in that case there wre PIREPs that reported =no= icing.
BTW, the excerpt is a quote is from an older decision. As of 1974, the NTSB had "long viewed" this.
There's an even later decision (from 2005) which is even scarier than the SIGMET one. A CFII got nailed for flying in "known icing" without even an Airmet or a Sigment. There were some PIREPs away from his route of flight. The NTSB said that given even remote PIREPS, he should have asked. But it's the unnecessary addition of the following that is interesting:
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Here, respondent knew that he would be flying into clouds that contained moisture, knew that the temperature on the ground at his destination was close to freezing, and knew that in the cloudy skies on the way to and above Payne Field the temperature would be colder. The risk of icing was clear. Respondent nevertheless chose to make the flight,
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http://www.ntsb.gov/O_n_O/docs/AVIATION/5154.PDF