This SAE Recommended Practice describes an empirical method for determining the theoretical ash content of aviation piston engine lubricating oils by calculating the equivalent weight of metallic oxides formed at 775 °C based on the metallic elemental concentration. The calculation method of ash determination may be used as an alternate to ASTM D 482 for application to the standards for aviation piston engine lubricating oils.
This standard was revised based on recommendations made at the 22 April 2010 SAE E-38 Aviation Piston Engine Fuels and Lubricants Committer meeting. It is part of the standard SAE five-year review process and it includes only editorial changes. The name of the preparing SAE committee has changed to E-38 and is now under the Aerospace Council.