Common Aviation Fuels, Mogas
The fact that mogas contains bio-alcohol has several implications for the experimental aircraft owner. The current European fuel standard EN 228 allows upto 3 vol-% methanol and 5 vol-% ethanol without further declaration. It is expected that other parts of the world may follow soon.
Aeronautical Information Circular 04-07
The use of automotive gasoline (mogas) containing bio-alcohol in aircraft.
Excerpt from the document:
Several aircraft equipped with piston engines are approved for operation with automotive gasoline (Mogas). These approvals may be limited to the use of Mogas that does not contain low-molecular weight alcohols (methanol or ethanol). However, not all (Supple- mental) Type Certificated products have this limitation. The current European fuel standard EN 228 allows up to 3 vol-% methanol and 5 vol-% ethanol without further declaration.
While in the past most of the fuel did not contain methanol or ethanol, this situation has changed due to implementation of the “Directive 2003/30/EC of the European Parliament and of the Council of 8 May 2003 on the promotion of the use of biofuels or other renewable fuels for transport” in the EU member states. It is anticipated that the amount of alcohol added to the fuel will increase even further in the future.
To continue reading see the pdf below: