What are the four levels of icing?

• A. Trace, Light, Moderate, Severe
• B. Light, Moderate, Severe, Extreme
• C. Trace, Moderate, Light, Severe
• D. Light, Trace, Severe, Moderate

Answer: (A)

Icing intensity is categorized into four levels that describe how much ice accumulates on the airframe and how that ice affects performance and handling. Start with trace icing, which is just detectable ice on surfaces but does not significantly change flight characteristics or require major changes in operation. Move to light icing, where the ice is more noticeable and begins to add drag and weight; you can usually continue with some caution and the airplane’s anti-icing/de-icing systems functioning. Then comes moderate icing, where the accumulation is clearly affecting performance—stall characteristics, controllability, and required power settings change more noticeably, and you’d plan to adjust course or altitude or depart icing conditions if possible. Finally, severe icing represents rapid, heavy accumulation that can overwhelm the aircraft’s systems and degrade control, typically requiring immediate action to exit the icing or find a safe place to land.

So the four levels are trace, light, moderate, and severe.