If normal electrical power is lost, which statement describes the failure of Wing anti-ice and Engine anti-ice valves?

If normal electrical power is lost, which statement describes the failure of Wing anti-ice and Engine anti-ice valves?

• A. Wing opens; Engine closes
• B. Wing closes; Engine opens
• C. Wing remains in last commanded position
• D. Wing opens; Engine opens

Answer: (B)

When electrical power is lost, the anti-ice valves in the A320 bleed/anti-ice system go to their fail-safe positions due to the way their actuators are designed. The wing anti-ice valve is spring-loaded to close, so without power it automatically returns to the closed position, preventing bleed air from going to the wing leading edge. The engine anti-ice valve is spring-loaded to open, so loss of power allows it to spring to the open position, keeping engine nacelle/air intake anti-ice provision active if needed. This combination results in the wing anti-ice being off while the engine anti-ice is on when power is lost.

When electrical power is lost, the anti-ice valves in the A320 bleed/anti-ice system go to their fail-safe positions due to the way their actuators are designed. The wing anti-ice valve is spring-loaded to close, so without power it automatically returns to the closed position, preventing bleed air from going to the wing leading edge. The engine anti-ice valve is spring-loaded to open, so loss of power allows it to spring to the open position, keeping engine nacelle/air intake anti-ice provision active if needed. This combination results in the wing anti-ice being off while the engine anti-ice is on when power is lost.