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Aircraft general knowledge

8.5 Aviation fuel
(Generel viden om luftfartøjer 2 - 6 videoer)

Most of our small aircraft fly on gasoline. Some, especially the newer ones, fly

on diesel. The aircraft of the future may fly on electricity.

8.5.1 Aviation gasoline

There is extensive quality control of aviation gasoline. The gasoline companies

ensure the quality of the gasoline, right up until it is filled in the tank.

Gasoline is leaded to reduce knocking. Gasoline’s knocking resistance is indicated

by the so-called octane number or performance number.

8.5.1.1 Types of gasoline

Aviation gasoline is divided into classes with regard to:

- octane number

- grade

Gasoline is leaded to reduce knocking. The knocking resistance of gasoline is

indicated by the so-called octane number or performance number.

TEL (Tetra Ethyl Lead) is used to prevent knocking in engines and to lubricate, for

example, valve seats. 1g contains 640 mg of lead.

Gasoline can also be classified according to the grade system. It is indicated with

two or three numbers, for example from 80 to 87.

We use avgas 100LL with an octane number of 100 and low lead content for most

aircraft. Today, 100LL is used all over the world.

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 702