With loss of normal electrical power, the Wing Anti-ice valves fail ________, and the Engine Anti-ice valves ________.

With loss of normal electrical power, the Wing Anti-ice valves fail ________, and the Engine Anti-ice valves ________.

• A. Open; closed
• B. Open; open
• C. Closed; open
• D. Closed; closed

Answer: (C)

When electrical power is lost, the two anti-ice valve systems are designed to go to different default positions to protect the aircraft in icing conditions. The wing anti-ice valve is spring-loaded to a closed position, so with no power it shuts off bleed air to the wing leading edge. The engine anti-ice valve is spring-loaded to an open position, so without power the engine anti-ice circuit remains supplied if bleed air is available. This combination keeps engine ice protection active as long as bleed air can reach it, while avoiding unintended wing anti-ice operation and bleed air use in a loss-of-power condition.

When electrical power is lost, the two anti-ice valve systems are designed to go to different default positions to protect the aircraft in icing conditions. The wing anti-ice valve is spring-loaded to a closed position, so with no power it shuts off bleed air to the wing leading edge. The engine anti-ice valve is spring-loaded to an open position, so without power the engine anti-ice circuit remains supplied if bleed air is available. This combination keeps engine ice protection active as long as bleed air can reach it, while avoiding unintended wing anti-ice operation and bleed air use in a loss-of-power condition.