Susceptibility of Mil-L-23699 (ACFT Turboshaft Engine, Synthetic Lube Oil) and Mil-L-7808 (Lubricating Oil ACFT Turbine Engine, Synthetic Base) Oils to Microbial Attack

摘要

A 6-month tropic service test of the OH-58A Helicopter System conducted at Fort Clayton, Canal Zone revealed that the tail rotor transmission oil level sight gage did not indicate the correct oil level because fungal growth plugged the sight gage drain holes. A sample of the MIL-L-23699 oil revealed it would readily support fungal and bacterial growth. A survey and test program to determine the microbial susceptibility of the MIL-L-23699 and MIL-L-7808 synthetic engine and transmission lubricants was undertaken. Of the 33 QPL samples of new and used lubricants obtained, only three were found to be resistant to microbial attack. The test microorganisms appeared to attack both the pentaerythritol and trimethylolpropane major basestock components with equal ease. The three microbially resistant products were all manufactured by one company and microbial resistance was probably due to either a side-effect of the gear load carrying additive employed or its instability in the test system employed. (Modified author abstract)