26.18 Fuel

26.18.2 Explain the differences between aviation gasoline (AVGAS) and motor gasoline (MOGAS).

Aviation gasoline (AVGAS) and motor gasoline (MOGAS) differ in several key aspects:

1. Composition:

AVGAS is specifically formulated for aviation engines and typically contains higher octane ratings, which help prevent engine knocking under high power conditions.

MOGAS, on the other hand, is designed for use in automotive engines and has a lower octane rating.  Some aircraft have automotive and Rotax engines using MOGAS.

2. Additives:

AVGAS often contains specific additives to enhance performance, such as anti-knock agents like tetraethyl lead (in some types) and other compounds to improve stability at high altitudes.

MOGAS, on the other hand, contains different additives focused on improving combustion efficiency and reducing emissions in automotive engines.

3. Volatility and Performance:

AVGAS is designed to maintain performance at various altitudes and temperatures, which is essential for flight operations.

MOGAS may not perform as reliably in the variable conditions experienced during flight, particularly at higher altitudes.