Definition
Automotive gasoline used as a fuel for some piston aircraft engines under a Supplemental Type Certificate (STC). It is chemically different from aviation gasoline (avgas) and, if spilled on composite aircraft surfaces, can soften or damage the resin matrix that holds the structure together.
Plain English
Car gas. In aviation, it refers to ordinary automotive gasoline that some aircraft are approved to burn instead of avgas. It can harm composite aircraft skins if spilled on them.
Context Anchor
Seen in discussions of fuel types, approved aircraft fuels, and cleaning up fluid spills on composite aircraft surfaces.
Derivation
Auto is short for automobile, and gas is short for gasoline. The term points to gasoline made for cars, which helps separate it from aviation gasoline made specifically for aircraft.
Why Pilots Care
Spills can damage composite resins if not cleaned with approved methods.
Grounding Statement
If auto gas is spilled on a composite aircraft surface, treat it as a chemical spill: remove it promptly and follow the aircraft’s maintenance guidance.
Intuition Check
Auto gas does not mean an automatic fuel system or any gasoline that happens to be available. Here it means automotive gasoline, and it is acceptable in an aircraft only when that aircraft is approved to use it.
Example Sentence 1
The owner installed an STC that allowed the aircraft to run on auto gas instead of 100LL.
Example Sentence 2
The checklist warns against using auto gas near composite parts during refueling.