Definition
Chemical compounds produced from methanol (a type of alcohol) that are sometimes blended into automotive gasoline as oxygenates or octane enhancers. The most common is methyl tertiary butyl ether (MTBE). These additives are not approved for use in aviation gasoline and can cause serious problems if auto fuel containing them is used in an aircraft.
Plain English
Chemicals made from methanol that are sometimes added to car gasoline. They are not allowed in aviation fuel because they can damage aircraft fuel systems.
Context Anchor
Seen in fuel system and fuel approval discussions, especially when checking whether automotive gasoline is approved for use in a specific aircraft.
Derivation
Methanol comes from 'methyl' (the simplest alcohol group) plus 'alcohol.' A 'derivative' is something derived, or made, from a parent substance. So a methanol derivative is a chemical built from methanol as a starting ingredient.
Why Pilots Care
Certain methanol derivatives can swell or degrade rubber seals, hoses, and fuel system components not designed for them, leading to leaks or engine issues.
Grounding Statement
If the aircraft approval says not to use fuel containing methanol derivatives, the safe reading is: do not use fuel with methanol-based additives unless the aircraft’s approved data specifically permits it.
Intuition Check
Do not assume “methanol derivatives” means only straight methanol. In this context, it can include related fuel additives made from methanol, and those can still matter for aircraft fuel approval.
Example Sentence 1
Before fueling the aircraft from the auto gas pump, the pilot tested a sample to confirm it contained no alcohol or methanol derivatives.
Example Sentence 2
Newer fuel specifications limit methanol derivatives to protect legacy aircraft fuel systems.