Title: Describe aircraft fuel.
Course: Aircraft Pilot Training I (20053-I) > Section: Examining Aircraft Instruments, Components, Systems, and Performance

Description should include the following:

- Aviation gasoline (AVGAS) is identified by an octane or performance number (grade), which designates the antiknock value or knock resistance of the fuel mixture in the engine cylinder.
- The higher the grade of gasoline, the more pressure the fuel can withstand without detonating.
- Lower grades of fuel are used in lower-compression engines, because these fuels ignite at lower temperatures.
- Higher grades are used in higher-compression engines because they ignite at higher temperatures, but not prematurely.
- If the proper grade of fuel is not available, use the next higher grade as a substitute. Never use a grade lower than recommended.

PLT130