The wing anti-ice valve shutoff limit is not more than how many turns during servicing?

• A. 1/4 turn
• B. 1/2 turn
• C. 1 turn
• D. 3/4 turn

Answer: (D)

The principle here is to protect the valve and its linkage by limiting how far you rotate it during servicing. For the wing anti-ice shutoff valve, the maximum travel during servicing is three-quarters of a turn. This small, controlled movement is enough to verify operation without over‑stressing the valve, seat, or actuator, which could cause leaks or mispositioning when the system is reassembled and actuated in flight. Rotating less than that (quarter or half turn) may not allow proper verification, while a full turn could exceed the mechanical stop and risk damage.