This method is designed to evaluate the changes in the chemical and physical properties of gas turbine engine lubricants subjected to elevated temperaures in the presence of air. The results are primarily applicable to low-oil-consumption gas turbine engines which do not experience regular additions of top-off oil. This is the initial documentation of this procedure and is intended to harmonize test procedures and report. The industry will need to conduct a round robin based on this procedure to develop precision statements.
Rationale: The Aerospace Standard AS5780 Specification for Aero and Aero-derived Gas Turbine Engine Lubricants requires data reporting obtained by this procedure for new oil qualification, management of change and periodic reviews. This ARP will harmonize reporting across the industry.