本文件讨论了与航空航天液压系统设计相关的液压流体物理和化学性质的相对优点，以及相关材料的兼容性。本报告中的讨论适用于碳氢化合物和磷酸酯基飞机液压油。在某些情况下，会提出数值限制，但一般来说，属性的重要性和影响是定性的。

This document discusses the relative merits of the physical and chemical properties of hydraulic fluids in relation to the aerospace hydraulic system design, and the related materials compatibility. The discussion in this report applies both to hydrocarbon and phosphate ester based aircraft hydraulic fluids. In some cases, numerical limits are suggested, but, in general, the significance and effect of a property is noted qualitatively.