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.
The update implements multifold revisions to the document. The title was changed to describe better the content of the document, which discusses the significance and relevance of aircraft hydraulic fluid properties, rather than being an compilation of typical fluid properties. Scope was extended to include phosphate ester hydraulic fluids used in commercial aircraft. Referenced test methods and property descriptions were updated, where appropriate. Sections that did not relate to physical and chemical properties of aircraft hydraulic fluids were deleted.