What triggers the CG control to close valves in the affected tank?

• A. If fuel in tank #4 becomes excessive.
• B. If fuel in tank #1 becomes excessive.
• C. If any tank becomes empty.
• D. If the aircraft climbs above 30,000 ft.

Answer: (A)

The main idea is that the CG control system actively manages fuel distribution to keep the aircraft’s center of gravity within safe limits. It monitors how much fuel is in each tank and can isolate a tank by closing its valves if that tank is carrying too much fuel. When fuel in tank #4 becomes excessive, the system closes the valves in that tank to stop any further accumulation there, helping to prevent the CG from shifting beyond acceptable limits and allowing redistribution of fuel to restore balance.

Altitude changes or a tank being empty aren’t the triggers for closing valves in the affected tank. Closing valves is specifically tied to an excessive quantity in that particular tank to maintain controllability and structural safety.