Shell AeroShell Fluid 31
Shell AeroShell Fluid 31 is a synthetic hydrocarbon-based aircraft hydraulic fluid developed to provide significantly improved fire resistance compared with conventional petroleum-based hydraulic fluids. It is formulated using a specially designed base stock that delivers a relatively high flash point, excellent low-temperature properties and strong oxidation and thermal stability.
The fluid incorporates advanced additive technology to provide effective oxidation and corrosion resistance, anti-wear protection and anti-foaming characteristics. In addition, Shell AeroShell Fluid 31 is superclean filtered to ensure optimum performance in particulate-monitored hydraulic systems, helping maintain system reliability and component longevity. The product is dyed red for identification purposes and has a useful operating temperature range of –40°C to +205°C.
Shell AeroShell Fluid 31 is recommended for use in aircraft, ordnance and missile systems operating across a wide temperature range. Typical applications include autopilots, shock absorbers, brakes, flight control systems, hydraulic servo-controlled systems and other hydraulic systems utilising synthetic elastomer seals. Increasingly, aircraft manufacturers specify this type of hydraulic fluid in preference to mineral hydraulic oils due to its enhanced fire-resistant properties.
The product is also approved for use in Honeywell (formerly Garrett) cooling turbines (cabin air compressors) and is widely adopted in military aircraft hydraulic systems. Shell AeroShell Fluid 31 is compatible with Shell AeroShell Fluids 41 and 61 and may be used in systems designed to operate with MIL-PRF-5606, MIL-PRF-6083, MIL-PRF-87257 and MIL-PRF-46170 fluids.
Performance characteristics include strong low-temperature fluidity, a high flash and fire point for improved safety margins, controlled evaporation loss and excellent corrosion and oxidation stability during extended high-temperature operation. The fluid passes stringent wear testing, including multiple 4-ball wear scar evaluations, supporting reliable anti-wear performance under load. It also meets strict cleanliness, water content and flame propagation requirements.
Shell AeroShell Fluid 31 meets MIL-PRF-83282D, carries NATO Code H-537 and Joint Service Designation OX-19, and complies with French DCSEA 437/A. As a synthetic hydrocarbon fluid, it should not be used with incompatible seal materials. Chlorinated solvents should not be used for cleaning components in systems containing this fluid, as solvent contamination may lead to corrosion.
