Definition
A type of valve that controls the flow of a fluid or gas by sliding a flat or cylindrical plate across one or more ports, opening and closing them as it moves. In aviation systems, slide valves are used in some hydraulic and pneumatic components where smooth, linear actuation is needed to direct flow between passages.
Plain English
A valve that opens and closes by sliding a plate back and forth across holes, letting fluid or air through when the holes line up and blocking it when they don't.
Context Anchor
Seen in aircraft maintenance and system descriptions where a component controls flow inside an engine, pump, regulator, or other mechanical unit.
Derivation
Slide comes from an old word meaning to move smoothly along a surface. Valve comes from a Latin word for a folding door or leaf. Together, the words point to a flow-control part that opens and closes by sliding like a small door.
Why Pilots Care
A slide valve that sticks, wears, or leaks may keep a system from controlling flow correctly, which can lead to rough operation or a component that does not respond as expected.
Analogy
Think of a sliding door on a cabinet: when it lines up with the opening, things can pass through; slide it over, and the opening is sealed.
Intuition Check
A slide valve is not necessarily a valve that the pilot slides by hand. The name describes how the valve works inside the component: one part slides to cover or uncover openings.
Example Sentence 1
The slide valve shifted position to redirect hydraulic fluid to the opposite side of the actuator.
Example Sentence 2
A worn slide valve in the fuel control unit caused uneven engine response during climb.