Definition
In an aircraft oxygen system, a device that controls the flow and pressure of oxygen delivered from the storage cylinder to the mask, reducing high cylinder pressure to a usable level and metering oxygen to the user according to demand or altitude.
Plain English
The part of the oxygen system that takes high-pressure oxygen from the bottle and delivers it to your mask at a safe pressure and the right amount.
Context Anchor
Seen when learning how aircraft oxygen systems deliver oxygen from the storage tank to a mask or outlet.
Derivation
From Latin regula, meaning 'rule' or 'straight stick used as a measure.' A regulator is literally something that 'rules' or controls — in this case, controlling pressure and flow rather than measuring length.
Why Pilots Care
Proper regulator function prevents hypoxia by delivering the correct oxygen quantity; a faulty unit can deliver too little or too much, creating immediate safety risks.
Analogy
A regulator is like the control on a garden hose nozzle: the water may be under pressure in the hose, but the nozzle controls how much comes out in a usable way.
Intuition Check
Do not read regulator here as a government rule or agency. In this context, it means a physical device that controls oxygen pressure and flow.
Example Sentence 1
During preflight, she checked the oxygen cylinder pressure and confirmed the regulator was delivering flow to her mask.
Example Sentence 2
During the climb the regulator automatically increased oxygen delivery as cabin altitude rose.