Definition
Gasoline formulated for automobile engines, sometimes referred to as autogas or mogas. It may be used in certain aircraft only when those aircraft and engines have been specifically approved for it through a Supplemental Type Certificate (STC) or by the manufacturer. Automobile gasoline differs from aviation gasoline in volatility characteristics, additive content, and resistance to vapor lock at altitude, and is not interchangeable with aviation gasoline unless explicitly authorized.
Plain English
The same kind of gasoline sold at car fuel stations. Some aircraft are approved to use it, but most are not. You can only put it in an aircraft if a specific written approval allows it for that aircraft and engine.
Context Anchor
You may see this term in fuel and oil discussions, in an airplane’s operating handbook, on fuel placards, or when checking what fuel is allowed before refueling.
Why Pilots Care
Aircraft not specifically approved for it can suffer detonation, vapor lock, or corrosion because automobile gasoline lacks the high-octane stability and anti-icing additives required at altitude.
Intuition Check
Do not assume “gasoline is gasoline.” Automobile gasoline is not automatically acceptable for an aircraft; the airplane, engine, and fuel must all match the approval.
Example Sentence 1
The owner installed an STC that allows the aircraft to operate on automobile gasoline, provided it is ethanol-free and meets the specified octane rating.
Example Sentence 2
The owner consulted the aircraft flight manual before considering a switch to automobile gasoline under an approved supplemental type certificate.