How is fuel jettisoned from an aircraft if needed?

Fuel jettisoning from an aircraft is primarily accomplished through dedicated jettison valves. These valves are specifically designed to allow for the quick and efficient release of fuel from the aircraft's fuel system. When activated, they open to release fuel from designated fuel tanks, allowing the aircraft to reduce its weight, particularly in emergency situations such as needing to return to land shortly after takeoff or during an in-flight emergency where excess weight must be eliminated.

Dedicated jettison valves are engineered to work under the specific pressure and flow requirements of the fuel system, ensuring safe and effective fuel release. This controlled method of jettisoning fuel is crucial, as it minimizes the risk of fuel contamination and ensures that the remaining fuel can be managed appropriately for the remainder of the flight.

Other methods mentioned in the options, while they might relate to fuel systems, are not primarily used for jettisoning fuel in a controlled manner. Gravity feeding systems typically relate to fuel delivery to engines and don't serve the functionality required for fuel jettisoning. Engine thrust could theoretically expel fuel, but this is not a practical or controlled method for fuel management during jettisoning. Manual release mechanisms are less common and could introduce complications or delays in an emergency situation where