Definition
A small, portable oxygen cylinder with an attached mask or regulator, used by a crew member to maintain a supply of supplemental oxygen while moving away from the aircraft's fixed oxygen system. It allows the user to remain on oxygen during short tasks at altitude, such as moving through the cabin or attending to passengers, before reconnecting to the main system.
Plain English
A small oxygen tank a crew member can carry around so they keep breathing oxygen while away from the aircraft's built-in oxygen supply.
Context Anchor
Seen in aircraft oxygen system discussions, cabin safety procedures, and checks of portable emergency oxygen equipment.
Derivation
Named for its purpose: it lets the user 'walk around' the cabin while still receiving oxygen, rather than being tethered to a fixed supply point.
Why Pilots Care
Allows safe movement without risk of hypoxia when fixed oxygen systems cannot be used.
Intuition Check
Do not confuse this with a water bottle or with the pilot’s outside preflight walk-around. Here, “bottle” means an oxygen pressure container, and “walk-around” means portable enough to use while moving in the aircraft.
Example Sentence 1
After the cabin altitude warning, the first officer grabbed the walk-around bottle before leaving the cockpit to check on the passengers.
Example Sentence 2
During the high-altitude preflight, the captain used the walk-around bottle to check the wing surfaces.