Which type of hydraulic fluid is used in this aircraft?

The correct choice of mineral-based hydraulic fluid, dyed red, is prevalent in many aircraft systems due to its specific properties. Mineral-based hydraulic fluids are derived from petroleum and provide excellent lubrication, anti-foaming, and corrosion resistance characteristics that are essential for the reliable operation of hydraulic systems under various temperature and pressure conditions. The dyeing of the fluid red serves a practical purpose; it helps in identifying the hydraulic fluid during maintenance checks and aids in spotting leaks, ensuring that any issues can be quickly detected and addressed.

Water-based fluids are less commonly used in aviation because they typically do not provide the high-performance lubrication and temperature stability required for aircraft operations. Biodegradable fluids, while environmentally friendly, are not as widely used in traditional aircraft systems, and their performance can vary significantly. Petroleum-based hydraulic fluids, while related to mineral-based fluids, do not have the same specific formulation and properties that mineral-based fluids offer.