Most helicopters are not certified to fly in known icing conditions, and there are many good reasons for that. • Icing conditions were not forecast, except for inside the snow shower clouds. • The IBF system did not fullfil the certification requirements for icing protection. • The Norwegian coast is exposed to winter conditions that are conducive to icing in the IBF system. Understand and Respect Icing ConditionsThe definition of icing condition varies among different regulators, OPS manuals, and even pilots.