Definition
A colorless, flammable hydrocarbon gas (C3H8) of the paraffin series, derived from natural gas and petroleum refining. It is stored as a liquid under moderate pressure and used as a fuel for heating, cooking, and ground-based equipment. In aviation, propane is most commonly associated with hot air balloons, where it is burned to heat the air inside the envelope and provide lift.
Plain English
A fuel gas that is kept as a liquid in a pressurized tank and burns with a hot flame. In flying, it is best known as the fuel that heats the air in a hot air balloon.
Context Anchor
Pilots most often encounter propane in hot-air balloon operations and around fuel cylinders used for burners or heaters.
Derivation
From the chemical naming system: 'prop-' indicates three carbon atoms, and '-ane' marks it as a saturated hydrocarbon (the same family as methane and butane). Knowing this places propane in the same family of clean-burning fuel gases.
Why Pilots Care
Balloon pilots must understand propane handling, tank pressure behavior in cold weather, and burner operation, since the fuel directly controls climb, descent, and level flight.
Grounding Statement
A propane cylinder holds liquid fuel under pressure, and the released gas is what actually burns.
Example Sentence 1
The balloon pilot checked the propane tanks before sunrise to confirm enough fuel for the morning flight.
Example Sentence 2
Before launch the crew verified that both propane tanks held adequate pressure and fuel quantity.