Definition
A fuel system icing inhibitor additive blended into aviation gasoline in small, controlled concentrations to prevent water suspended in the fuel from freezing and forming ice crystals that could block fuel filters or fuel lines at low temperatures.
Plain English
A chemical added to fuel in tiny amounts to stop water in the fuel from freezing and clogging the fuel system when it's cold.
Context Anchor
Seen in fuel-system discussions about preventing water-related fuel icing, especially in procedures for cold-weather or high-altitude operations.
Derivation
From chemistry naming: 'ethylene glycol' is a well-known antifreeze compound, and 'monomethyl ether' describes a specific chemical modification of it. Knowing the 'glycol' part links it mentally to antifreeze, which is exactly what it does in the fuel — it keeps water from freezing.
Why Pilots Care
Uninhibited water in fuel can freeze at altitude and cause engine stoppage; EGME provides reliable protection without damaging engine components.
Grounding Statement
If water in the fuel freezes, it can become ice in places where fuel needs to keep moving; EGME lowers that risk.
Intuition Check
EGME is not the same as the deicing fluid sprayed on wings, and it is not engine coolant. In this context, it is a fuel additive used to help prevent fuel-system icing.
Example Sentence 1
Before the cold-weather flight, the mechanic added EGME to the fuel at the manufacturer's specified concentration to prevent ice from forming in the fuel lines.
Example Sentence 2
Preflight checks confirmed the EGME concentration met the level needed to prevent fuel icing.