When must Wing Anti-ice not be used?

The use of Wing Anti-ice is specifically avoided during ground operations or for takeoff primarily to prevent potential engine performance issues and aerodynamic impairments. In these phases of flight, the aircraft is often at lower speeds, and the application of wing anti-ice can alter the airflow over the wings and lead to reduced lift. Ice accumulation is typically a concern during ascent, so it is critical to ensure that the surfaces are free of ice before takeoff.

In cruise flight, the wing anti-ice system may be employed if there are indications of ice accumulation, as the aircraft can handle those conditions better at higher speeds and altitudes. Regarding landing in wet conditions, the system may also be utilized depending on the specific situation and pilot discretion. The restriction below 10,000 feet isn't absolute since the decision to deploy wing anti-ice can depend on several factors including temperature and weather conditions, rather than solely altitude.