Definition
A valve that takes a higher-pressure fluid supply and delivers it downstream at a lower, regulated pressure, holding that lower pressure steady regardless of changes in the upstream supply or downstream demand.
Plain English
A valve that takes high-pressure fluid coming in and lets it out at a lower, steady pressure on the other side.
Context Anchor
Seen in aircraft hydraulic and pneumatic system descriptions, troubleshooting steps, and maintenance manuals where one part of a system must operate at a lower pressure than the main supply.
Why Pilots Care
Prevents damage to lines, seals, and components from excessive pressure that could cause system failure or leaks.
Analogy
It works like a water pressure regulator in a building: strong supply pressure comes in, but the equipment after the regulator receives a lower, safer pressure.
Intuition Check
Do not think of a pressure reducing valve as simply dumping pressure overboard. Its job is to supply a lower controlled pressure on the outlet side.
Example Sentence 1
The brake system uses a pressure reducing valve so the wheel brakes receive a lower pressure than the main hydraulic system.
Example Sentence 2
Maintenance confirmed the pressure reducing valve was holding the outlet pressure steady before returning the aircraft to service.