When are ENGINE/WING STAB anti icing systems turned on?

When are ENGINE/WING STAB anti icing systems turned on?

• A. ENGINE: When in icing conditions with 10 degrees Celsius, invisible moisture, or less than one statute mile visibility
• B. ALL: Amber ICING message displays on EICAS or EIS
• C. ALL: Icing accumulation is observed by pilot
• D. ENGINE: Only when shown by a specific cockpit alert

Answer: (A)

Engines, wing, and tail anti-ice are activated whenever the aircraft is in icing conditions to prevent ice from building up on critical surfaces. In this airplane, icing conditions are defined by the presence of moisture and the temperature range where icing can occur. The trigger described—icing conditions with a temperature around 10°C or below, or the presence of invisible moisture (fog/cloud) or very low visibility (less than one mile)—shows the environmental cues that indicate icing risk. When these cues are present, the anti-ice systems are turned on to protect the engine inlets, wing leading edges, and tail surfaces from ice accretion. The other options rely on warnings or pilot observations rather than the environmental triggers that mandate activation. An amber icing message on EICAS/EIS is a warning, not the automatic trigger for turning on anti-ice. Icing accumulation observed by the pilot is itself a reaction to icing, not the predefined condition that initiates anti-ice. And relying solely on a cockpit alert to decide to engage the system ignores the standard automatic or procedure-based response to actual icing conditions.

Engines, wing, and tail anti-ice are activated whenever the aircraft is in icing conditions to prevent ice from building up on critical surfaces. In this airplane, icing conditions are defined by the presence of moisture and the temperature range where icing can occur. The trigger described—icing conditions with a temperature around 10°C or below, or the presence of invisible moisture (fog/cloud) or very low visibility (less than one mile)—shows the environmental cues that indicate icing risk. When these cues are present, the anti-ice systems are turned on to protect the engine inlets, wing leading edges, and tail surfaces from ice accretion.

The other options rely on warnings or pilot observations rather than the environmental triggers that mandate activation. An amber icing message on EICAS/EIS is a warning, not the automatic trigger for turning on anti-ice. Icing accumulation observed by the pilot is itself a reaction to icing, not the predefined condition that initiates anti-ice. And relying solely on a cockpit alert to decide to engage the system ignores the standard automatic or procedure-based response to actual icing conditions.