Takeoff with ground contamination and/or visible moisture and OAT 5C or below: which anti-ice system is used?

• A. Cowls
• B. Wing and Cowls
• C. Wing only
• D. All surfaces

Answer: (B)

When icing risk is present during takeoff—specifically with ground contamination or visible moisture and an outside air temp of 5 °C or below—the surfaces most prone to ice are the wings' leading edges and the engine nacelles. Protecting both is essential. Wing anti-ice keeps the wing leading edges from accumulating ice, preserving lift and handling characteristics. Cowl anti-ice safeguards the engine nacelles and inlets from ice buildup, which can disrupt airflow into the engines. If you only heat one system, ice can still form on the unprotected surface, creating hazards to takeoff performance or engine operation. Therefore, the required setting is to have both wing and cowl anti-ice active for takeoff in these conditions.