A hazardous ice formation is one that can substantially degrade aircraft performance, cause handling problems, and, in the extreme, result in a stall or loss of control–in flight (LOC-I). Such a formation is characterized by its size or volume, shape, and location, especially when ice accretes on wings and tail surfaces. The cause may be an ice-protection system failure, pilot error or a severe icing condition — such as the presence of super-cooled large droplets — that overwhelms the protection system.
