Definition
A hydraulic system component that maintains operating pressure within a specified range by directing pump output to the system when pressure is low and routing it back to the reservoir, unloaded, when the desired pressure is reached. It allows a constant-displacement pump to run continuously without overpressurizing the system.
Plain English
A device that keeps the hydraulic system's pressure within safe limits. When the system has enough pressure, it sends the pump's flow back to the tank instead of forcing more fluid into the system.
Context Anchor
Seen in aircraft oxygen-system descriptions, servicing information, and maintenance checks involving pressure control.
Derivation
From Latin regula meaning 'rule' or 'straight piece of wood used as a measuring stick.' A regulator keeps something within set limits — here, the limit being system pressure.
Why Pilots Care
Prevents over-pressurization that could damage lines or actuators while ensuring consistent power for flight controls and landing gear.
Analogy
It is like a household water pressure regulator: the main supply may be at a high pressure, but the equipment in the house needs a lower, controlled pressure.
Intuition Check
Do not read “regulator” as just an on/off valve. A system pressure regulator’s job is to control pressure to a set usable level, not simply stop or start flow.
Example Sentence 1
When the system pressure regulator failed, the hydraulic pump kept building pressure until the relief valve opened.
Example Sentence 2
Mechanics adjusted the system pressure regulator after the pump was replaced to restore normal operating pressure.