AeroShell Fluid 31 Synthetic Hydrocarbon Fire Resistant Hydraulic Fluid
AeroShell Fluid 31 is a synthetic hydrocarbon based aircraft hydraulic fluid with greatly improved fire resistance characteristics when compared with conventional petroleum products.
AeroShell Fluid 31 has a specially designed base stock which imparts a relatively high flash point, excellent low temperature properties and good oxidation and thermal stability. In addition, AeroShell Fluid 31 is formulated with high technology additives to provide oxidation and corrosion resistance, antiwear, and anti-foaming protection.
AeroShell Fluid 31 is superclean filtered to ensure optimum performance in particulate monitored systems.
AeroShell Fluid 31 is dyed red.
The useful operating temperature range is -40 to +205°C.
ApplicationsAeroShell Fluid 31 is recommended for use in aircraft, ordnance, and missile systems operating from 40°C to +205°C . This fluid should be considered for use in auto pilots, shock absorbers, brakes, flight control systems, hydraulic servo-controlled systems and other systems using synthetic elastomer seals.
An increasing number of aircraft manufacturers now recommend use of this type of fluid in aircraft hydraulic systems in preference to mineral hydraulic oils. This move has been prompted by need to use fluids with better fire resistant properties.
AeroShell Fluid 31 is also approved for use in the Honeywell (formerly Garrett) cooling turbine (cabin air compressors).
Increasingly this type of hydraulic fluid is being adopted for use in hydraulic systems of military aircraft in place of mineral hydraulic fluids. AeroShell Fluid 31 is a synthetic hydrocarbon oil and should not be used in contact with incompatible seal materials. Refer to the General Notes at the front of this section for further information.
AeroShell Fluid 31 is compatible with AeroShell Fluids 4, 41, 51, 61 and 71 and can be used in systems designed to operate with MIL-PRF-5606, MIL-PRF-6083, MIL-PRF-87257 and MIL-PRF-46170 fluids.
Chlorinated solvents should not be used for cleaning hydraulic components which use AeroShell Fluid 31. The residual solvent contaminates the hydraulic fluid and may lead to corrosion.
Kinematic viscosity mm2/s
Particle Count, Automatic, per Lt
4-Ball Wear, 1 hr @ 75°C scar dia, mm
Oxidation & corrosion stability 168 hrs @ 121°C
A viscosity/temperature curve is shown at the end of this section