Flight operations: Wing anti-ice must be ON when which conditions?

• A. Ice annunciated by Ice Detection System
• B. Icing conditions with TAT <= 10C and visible moisture
• C. A/S < 230 KIAS in icing conditions
• D. All of the above

Answer: (D)

Wing anti-ice must be on whenever icing could form or is detected to protect the aircraft from ice buildup on the leading edges. If ice is annunciated by the Ice Detection System, that’s a clear signal to activate anti-ice. In icing conditions with a temperature at or below 10 C and visible moisture, ice can form quickly, so turning on wing anti-ice is required. At slower speeds (below 230 KIAS) in icing conditions, the risk of ice accumulation increases, so keeping anti-ice on is necessary. Because all of these situations call for anti-ice operation, the best answer is that all of the above apply.