SAE ARP 5921A:2026-03-13

This method is designed to evaluate the coking propensity of synthetic ester-based aviation lubricants under two phase air-oil mist conditions as found in certain parts of a gas turbine engine, for instance, bearing chamber vent lines. Based on the results from round robin data in 2008 to 2009 from four laboratories, this method is currently intended to provide a comparison between lubricants as a research tool; it is not currently a satisfactory pass/fail test.