How many wing anti-ice schedules are there?

• A. Three
• B. Two
• C. One
• D. Four

Answer: (B)

Wing anti-ice scheduling governs when and how aggressively heat is applied to the wing leading edges to prevent ice buildup. There are two schedules to cover both normal operation and a degraded/alternate path. In normal operation, the system uses icing conditions and flight phase to modulate heat, keeping the wing surface just above freezing when ice is possible while balancing bleed-air use. If the primary control path isn’t available, the alternate schedule provides a safe fallback heat pattern so protection continues even with a fault. This setup ensures reliable ice protection across a range of conditions without requiring manual intervention.