Definition
A gas that has been compressed and stored under pressure inside a sealed metal cylinder so it can be transported and used as needed. In aviation maintenance, common bottled gases include oxygen for crew and passenger breathing systems, nitrogen for servicing tires and shock struts, and various fuel or shielding gases used in shop work.
Plain English
Gas squeezed into a strong metal bottle so it can be carried around and used when needed.
Context Anchor
Seen in aircraft maintenance, servicing, welding, oxygen servicing, tire inflation, and shop safety discussions.
Derivation
Bottle comes from an old French word for a container. Gas refers to a substance like air or oxygen that spreads out to fill its container. Together, bottled gas means a gas held inside a container, not fuel gasoline in a bottle.
Why Pilots Care
Provides a reliable onboard supply of breathing oxygen or system gas when external sources are unavailable.
Intuition Check
Do not read “gas” here as gasoline or aviation fuel. In this term, “gas” means a substance such as oxygen, nitrogen, or carbon dioxide stored in a pressure cylinder.
Example Sentence 1
The mechanic used bottled nitrogen to service the landing gear struts to the correct pressure.
Example Sentence 2
During preflight the mechanic verified the pressure in all bottled gas cylinders.