Which statement best describes anticipated icing conditions?

• A. OAT/TAT <= 0 C with visible moisture
• B. OAT/TAT <= 10 C with no moisture
• C. OAT/TAT > 10 C with visible moisture
• D. OAT/TAT <= 10 C with visible moisture

Answer: (D)

Anticipated icing occurs when the air temperature is cold enough and there is visible moisture in the air. The best description is an air temperature at or below 10°C with visible moisture present. In that temperature range, moisture in the environment can begin to freeze on aircraft surfaces, increasing icing risk.

Visible moisture includes clouds, fog with droplets, rain, drizzle, snow, or ice crystals. If moisture isn’t present, icing won’t form even if the air is cold. If the temperature is above 10°C, icing is unlikely even with moisture.

So the statement that matches OAT/TAT at or below 10°C with visible moisture best describes anticipated icing conditions, while the others either restrict the range too much, reflect no moisture, or require a temperature above 10°C.