ASTM D6424-25

1.1 This practice covers ground based octane rating procedures for naturally aspirated spark ignition aircraft engines using primary reference fuels.

1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 This practice is used as a basis for determining the minimum motor octane requirement of naturally aspirated aircraft engines by use of PRFs.

5.2 Results from standardized octane ratings will play an important role in defining the actual octane requirement of a given aircraft engine, which can be applied in an effort to determine a fleet requirement.