What is the purpose of a fuel jettison system, and when is it typically used?

• A. To rapidly reduce landing weight when necessary; used on certain large aircraft under approved conditions.
• B. To improve takeoff performance by increasing fuel load.
• C. To adjust fuel temperature during flight.
• D. To purge fuel lines after maintenance.

Answer: (A)

Fuel jettison is used to rapidly shed fuel so the airplane’s weight at landing can be brought down to or below the maximum landing weight when necessary. This is especially important for large aircraft that may arrive with more fuel than the landing limit due to holding, diversions, or required reserves. By dumping fuel from dedicated wing nozzles under controlled conditions, the crew can reach a safe landing weight without wasting time burning off fuel or performing a lengthy hold.

The operation is tightly controlled and typically requires approval and clearance from air traffic control, and it’s done in flight away from populated areas to minimize risk and environmental impact. It is not a method to improve takeoff performance by adding fuel, it does not adjust fuel temperature, and it isn’t a procedure used to purge fuel lines after maintenance.