Definition
A specialized high-octane gasoline formulated for use in piston-engine aircraft. AVGAS is distinct from automotive gasoline and from jet fuel: it is blended for stable performance at altitude, resistance to detonation under high cylinder pressures, and reliable vaporization across a wide temperature range. The most common grade in general aviation is 100LL (100 octane, low lead), which is dyed blue for visual identification.
Plain English
Aviation gasoline — the fuel used by piston-engine airplanes. It is not the same as the gasoline used in cars or the kerosene-based fuel used in jets.
Context Anchor
Seen on GPS nearest-airport pages, airport information listings, fuel signs, and preflight planning tools to show whether aviation gasoline is available at an airport.
Derivation
A contraction of "aviation gasoline." The name simply marks it as gasoline made for aircraft, distinguishing it from MOGAS (motor gasoline) and Jet A (jet fuel).
Why Pilots Care
Using the wrong fuel can cause engine failure or damage; confirming AVGAS prevents costly and dangerous mistakes during refueling.
Intuition Check
AVGAS does not mean any fuel used by airplanes. It specifically means aviation gasoline for gasoline-type aircraft engines, not jet fuel.
Example Sentence 1
Before departure, the pilot confirmed the fuel truck was delivering 100LL AVGAS and checked that the fuel sample was blue and free of contamination.
Example Sentence 2
Always double-check the fuel truck label to ensure it is dispensing AVGAS rather than Jet A.