Definition
The intentional release or discharge of fuel, cargo, stores, or other items from an aircraft in flight, typically performed in an emergency to reduce weight or eliminate a hazard.
Plain English
Deliberately dumping something out of the aircraft while flying, usually to make the aircraft lighter or safer in an emergency.
Context Anchor
Seen in emergency procedures, fuel-dumping discussions, and aircraft systems that allow a pilot or crew to release something from the aircraft.
Derivation
From the Old French 'getaison' (a throwing), itself from Latin 'jactare' meaning 'to throw.' The aviation use carries the same idea: deliberately throwing something overboard.
Why Pilots Care
Reduces aircraft weight quickly in emergencies, improving climb performance or preventing structural overload.
Analogy
Like tossing sandbags overboard from a balloon to gain altitude.
Intuition Check
Jettison does not mean something fell off by accident. It means the pilot, crew, or aircraft system intentionally released it.
Example Sentence 1
After the engine failure, the crew jettisoned fuel to bring the aircraft down to maximum landing weight before returning to the field.
Example Sentence 2
After losing an engine on takeoff, the pilot jettisoned cargo to maintain climb performance.