Definition
A cockpit-operated valve that allows the pilot to stop the flow of fuel from the airplane's fuel tanks to the engine. In most light airplanes it is combined with the fuel selector, which lets the pilot choose which tank feeds the engine or shut the supply off entirely.
Plain English
A control in the cockpit that turns the fuel supply to the engine on or off, and on many airplanes also picks which tank the fuel comes from.
Context Anchor
You will see this term in emergency procedures, especially engine fire checklists and fuel system discussions.
Derivation
Valve comes from an old word for a folding door. That helps here because a valve acts like a door for fuel: open lets fuel pass, closed stops it.
Why Pilots Care
Cutting fuel supply starves an engine fire of additional fuel, limiting damage and helping maintain aircraft control.
Grounding Statement
If the engine area is burning, the pilot wants to stop sending fuel toward that area as quickly and correctly as the checklist requires.
Intuition Check
The fuel selector shutoff valve is not the same as reducing engine power. Power controls how much the engine is asked to produce; this valve controls whether fuel is allowed to flow to the engine at all.
Example Sentence 1
When the engine caught fire on the ground, the pilot moved the fuel selector shutoff valve to OFF and continued the emergency checklist.
Example Sentence 2
During the engine fire checklist, confirming the fuel selector is in the shutoff position ensures no fuel reaches the flames.