When must wing and cowl anti-ice systems be activated?

The prompt specifies that wing and cowl anti-ice systems must be activated when ice is detected. This is critical for ensuring safe flight operations in conditions prone to icing. When ice forms on the wings or engine areas, it can significantly affect aircraft performance, including lift, drag, and overall control. By activating the anti-ice systems as soon as ice is detected, pilots can mitigate these risks and maintain safe flying conditions.

In contrast, activating these systems in non-icing conditions or only under specific temperature conditions is not appropriate, as they are designed to be used specifically when icing is a concern. Continuous operation at all times during flight is excessive and could lead to unnecessary wear and energy consumption. Thus, the correct timing for activating these systems is crucial to ensure both safety and efficiency.