Under what circumstances must the wing anti-ice system be turned ON?

The wing anti-ice system must be turned ON primarily when the ICE DETECTED CAS message is activated or when flying in known icing conditions. This is crucial for aircraft safety, as ice accumulation on the wings can significantly reduce lift and impact the aircraft's performance and controllability. The system is designed to prevent ice from forming on the wings, which can occur in specific temperature ranges and humid conditions during flight.

In contrast, while airspeed considerations and temperature may influence icing risks, they do not define the immediate need to activate the anti-ice system. The temperature being above 10°C suggests a lower risk of icing, and flying at lower altitudes does not inherently indicate that ice will form; instead, it's the presence of atmospheric conditions that are conducive to icing that triggers the need for the anti-ice system. Therefore, the critical factor remains the detection of icing conditions, making the activation of the system vital for safe operations in such scenarios.