Icing is considered severe when

• A. The rate of accumulation is such that anti-icing reduces the hazard
• B. The rate of accumulation is such that anti-icing/deicing equipment fails to reduce or control the hazard
• C. No icing present
• D. Only trace icing

Answer: (B)

Severe icing is reached when ice is accumulating so quickly that the aircraft’s anti-icing and de-icing systems can no longer prevent or remove the ice effectively. In this situation, the ice buildup outpaces the capability of heated surfaces, boots, or chemical de-icing, so the hazard cannot be reduced or controlled by the equipment in use. When icing remains unmanaged like this, lift declines, drag rises, and handling or control authority can be compromised, posing a real safety risk. If icing were only trace or nonexistent, or if the anti-icing/de-icing systems could still keep up and mitigate the hazard, it wouldn’t be considered severe.