The question of what constitutes known icing conditions and the legalities involved have been the subject of three articles by AVweb's Scott Puddy and a rebuttal by retired FAA inspector Eric Jaderborg. Scott took a close look at existing regulations and a celebrated enforcement case in which Eric participated. Now, it's Eric's turn again as he takes a close look at what the FAA thinks about icing, where it draws the line and why. Before you depart into icing conditions, read this. You may be risking more than you think.