Defueling is required in which scenario?

• A. Fuel tanks need maintenance
• B. Increase in cargo and the weight is too much
• C. When mission profile changes
• D. Needed when mission profile changes

Answer: (D)

Defueling is done to match the aircraft’s fuel load to what the mission actually requires. When the mission profile changes, the planned endurance and fuel needs often change as well. If the new plan calls for less flight time, shorter legs, or different routing/alternates, you remove the unused fuel so the airplane isn’t carrying more weight than necessary. This keeps takeoff and landing weights, as well as the center of gravity, within safe limits and preserves performance margins. The other scenarios don’t inherently trigger defueling: fuel tank maintenance is a separate maintenance action, and simply having more cargo doesn’t automatically mean you should defuel—the trigger is a change in the mission’s fuel requirements.