Which hydraulic oil number is commonly used in aircraft?

The hydraulic oil number that is commonly used in aircraft is MIL-PRF-83282. This specific type of hydraulic fluid is designed to operate at high temperatures and pressures, making it suitable for the demanding environments experienced in aviation. It offers excellent thermal stability, low temperature fluidity, and resistance to oxidation and corrosion, which are critical factors in maintaining the reliability and efficiency of aircraft hydraulic systems.

The importance of using the correct hydraulic fluid cannot be overstated, as it directly impacts the performance of hydraulic systems that control various functionalities, including landing gear, brakes, and flight control surfaces. MIL-PRF-83282 meets the requirements set forth by the military for use in aircraft, ensuring compatibility and reliability across a variety of defense platforms.

Other options listed, such as MIL-PRF-23699, MIL-PRF-10523, and MIL-PRF-27830, are used for different applications or types of fluids. MIL-PRF-23699 is typically a jet engine oil, while the others are designated for specific lubricating or non-hydraulic applications. Thus, they do not meet the criteria for hydraulic fluid use in aircraft systems.