Definition
A clear, colorless alcohol (chemical formula C2H5OH) produced by the fermentation of plant sugars or starches, used as a fuel or fuel additive. In aviation maintenance contexts, ethanol is significant because it is blended into many automotive gasolines and is generally not approved for use in aircraft piston engines, as it can damage fuel system components and absorb water.
Plain English
Ethanol is the kind of alcohol made from crops like corn or sugar cane. It can be burned as fuel, but it is not safe to use in most aircraft engines because it can harm seals, hoses, and tanks, and it pulls moisture out of the air.
Context Anchor
Seen in fuel discussions, aircraft fueling decisions, maintenance checks, and when considering automotive gasoline for an aircraft.
Derivation
From 'ethyl' (a chemical group containing two carbon atoms) plus '-ol' (the chemical suffix marking an alcohol). So ethanol literally means 'ethyl alcohol' — the specific alcohol found in beverages and used as fuel.
Why Pilots Care
Most certified aircraft engines are not approved for ethanol-blended fuels because it absorbs water and degrades rubber seals, hoses, and other components.
Intuition Check
Ethanol is not simply “better gasoline” or “cleaner fuel” in an aircraft. It is an alcohol added to some fuels, and the aircraft and engine must be approved to use fuel containing it.
Example Sentence 1
The mechanic warned the owner that pumping ethanol-blended gas into the aircraft could damage the fuel bladder over time.
Example Sentence 2
Using automotive gasoline with ethanol can corrode carburetor parts and fuel lines in piston engines.