Which condition allows anti-ice operation above 10 °C?

• A. Icing conditions indicated by the ICING annunciator or airframe ice accumulation
• B. When the ICING annunciator is off
• C. In cruise at altitude above 30,000 ft
• D. None of the above

Answer: (A)

Anti-ice operation is driven by the presence of icing conditions, not just a temperature value. On the Beechjet, you enable anti-ice when icing conditions are indicated or when there is actual ice accumulation on the airframe. The ICING annunciator in the cockpit is the cue for such conditions, and visible airframe ice confirms the need for protection. Therefore, the correct condition is the one that specifies icing conditions indicated by the ICING annunciator or airframe ice accumulation. If the ICING annunciator is off, there are no detecting icing conditions to justify anti-ice activation, and cruising at a high altitude by itself doesn’t mandate anti-ice.