X/C®5606J & X/C®5606A Aviation Hydraulic Fluids

Zinc-Free Antiwear Hydraulic Fluids

Phillips 66®X/C 5606J and X/C 5606A Aviation Hydraulic Fluids are mineral oil-based, high viscosity index, ashless (zinc-free) antiwear hydraulic fluids designed to meet the severe demands of aerospace and industrial applications. They have excellent oxidation resistance and outstanding low-temperature properties for use over a wide temperature range. They provide excellent wear protection for hydraulic pumps and motors, protect hydraulic system components against rust and corrosion, and are resistant to excessive foam buildup that can cause poor or sluggish hydraulic system response.


Features & Benefits

• Very high viscosity index for use over a wide temperature range

• Outstanding low-temperature properties

• Excellent wear protection

• Resists deposit formation and viscosity increase due to oxidation

• Protects against rust and corrosion

• Good foam resistance

• Does not contain zinc or other heavy metals


X/C Aviation Hydraulic Fluids are recommended for use in non-pressurized systems operating between –54°C and 90°C (-65°F to 194°F), and in pressurized systems operating between –54°C and 135°C (-65°F to 275°F) at pressures up to 3,000 psi.(1)

Typical applications include:

• Aircraft and missile control systems, autopilots and shock absorbers

• Auto wreckers, boom trucks and electrical service equipment (cherry pickers) where all-weather performance is required

• Industrial robotics

• Hydraulic systems that require a “super clean” fluid for extended service life and reliability (X/C 5606J)

(1) Note: Do not use these fluids in hydraulic systems with natural rubber elastomers.

Technical Details

Licenses & Approvals

X/C 5606J Aviation Hydraulic Fluid meets the requirements of:

• U.S. Military Specification MIL-PRF-5606H (supercedes MIL-O-5606, AN-O-336, AN-VV-O-336 and AAF-3580)

X/C 5606A Aviation Hydraulic Fluid meets the requirements of:

• U.S. Military Specification MIL-H-5606A (obsolete)

Additional Details
ISO Grade15
Gravity, °API31
Specific Gravity @ 60°F0.871
Density, lbs/gal @ 60°F7.25
Color, VisualRed
Flash Point (PMCC), °C (°F)90 (194)
Pour Point, °C (°F)-64 (-83)
Viscosity, Kinematic
cSt @ -54°C2450
cSt @ 40°C13.5
cSt @ 40°C495
cSt @ 100°C5.1
Viscosity Index382
Acid Number, ASTM D664, mg KOH/g0.05
Copper Corrosion, ASTM D130, 71°C (160°F), 72 hours1b
Dielectric Strength, ASTM D877, kV(2)49.6
Evaporation Loss, ASTM D972, 71°C (160°F), 6 hours, wt %13.6
Foam Resistance, ASTM D892, 75°F25-0
Four-Ball Wear, ASTM D4172, Scar Diameter, mm0.65
Gravimetric Filtration, FTM 313, mg/100 ml, 0.45 microns @ 25°C,
Filter time, minutes6
Particle Contamination, FTM 3012, Automatic Counter,
Particle Size, microns
Water Content, ASTM D6304, ppm60
(2)At the point of manufacture