Product Description

Mobil HyJet V is a Type V fire-resistant phosphate ester hydraulic fluid, which is superior in thermal and hydrolytic stability to commercially available Type IV hydraulic fluids. Better stability means the extent of fluid degradation in aircraft systems will be less than Type IV fluids, in-service fluid life will be longer, and consequently aircraft operator maintenance costs may be lower.

HyJet V provides excellent high and low temperature flow properties (kinematic viscosities) and rust protection. HyJet V has also demonstrated an improvement over the erosion protection performance afforded by Type IV fluids.

Features and Benefits

Mobil HyJet V offers the following key features and benefits:

Features Advantages and Potential Benefits
Higher stability than Type IV fluids Longer fluid life,

Lesser need to replace fluid due to degradation,

Reduced hydraulic system maintenance costs

Meets Boeing BMS 3-11 and SAE AS1241 Type IV and Type V requirements Improved flammability characteristics over meeting just the Type V requirements
Low density Reduced weight of the hydraulic fluid carried by aircraft,

Reduced aircraft fuel consumption,

Lower operating costs

Excellent rust protection Reduced risk of equipment damage in the event of major water contamination
Excellent low and high temperature viscosity balance Precise hydraulic system control and response even during extended range/polar flights,

Longer aircraft hydraulic system equipment life

Excellent deposit control Longer aircraft hydraulic system equipment life,

Reduced maintenance costs

Improved protection against electro-chemical corrosion (erosion) Protection against servo valve and pump damage
Fully compatible with all approved Type IV and Type V phosphate ester hydraulic fluids Flexibility in use by airline operators


Mobil HyJet V is designed for use in commercial aircraft phosphate ester hydraulic systems. It meets the SAE AS1241 requirements and is included in commercial and business airframe manufacturer Qualified Products Lists, as shown below. It is compatible in all proportions with commercial Type IV and Type V phosphate ester aviation hydraulic fluids.

Specifications and Approvals

This product has the following approvals:
AIRBUS NSA 307110N -Type V
BOEING, BMS 3-11P, Type V, Grade A and C
Boeing-Long Beach DMS2014H – Type 5
This product meets or exceeds the requirements of:
SAE AS1241D, Type V, Class 1 (low density), Grade A

Properties and Specifications

Acid Number, mgKOH/g, ASTM D974 0.04
Autoignition Temperature, F, ASTM D2155 >427 (800)
Bulk Modulus, Isothermal secant at 100 F/3000 psi, psi, ASTM D6793 210000
Calcium, ppm, ICPES 4
Chlorine, ppm, XRF 10
Coefficient of Thermal Expansion, 25 to 100 C, per degree C, API MPMS 11.1 0.00086 (0.00048)
Conductivity @ 20 C, MicS/cm, ASTM D2624 0.4
Density @ 60 F, lb/USg, ASTM D4052 1.000 (8.35)
Fire Point, Cleveland Open Cup, °F, ASTM D92 186 (366)
Flash Point, Cleveland Open Cup, °F, ASTM D92 174 (346)
Foam, Sequence I, Collapse Time, s, ASTM D892 32/18
Foam, Sequence II, Collapse Time, s, ASTM D892 23/13
Foam, Sequence III, Collapse Time, s, ASTM D892 34/19
Four-Ball Wear Test, Scar Diameter, 10 kg, 600 rpm, 1 h, 75 C, mm, ASTM D4172 (mod) 0.26
Four-Ball Wear Test, Scar Diameter, 4 kg, 600 rpm, 1 h, 75 C, mm, ASTM D4172 (mod) 0.21
Four-Ball Wear Test, Scar Diameter, 40 kg, 600 rpm, 1 h, 75 C, mm, ASTM D4172 (mod) 0.63
Kinematic Viscosity @ 100 F, mm2/s, ASTM D445 10.6
Kinematic Viscosity @ 127.6 C, mm2/s, ASTM D445 2.6
Kinematic Viscosity @ -15 F, mm2/s, ASTM D445 132
Kinematic Viscosity @ 210 F, mm2/s, ASTM D445 3.6
Kinematic Viscosity @ -65 F, mm2/s, ASTM D445 1350
Potassium, ppm, ICPES/AA 38
Shear Stability, % Kinematic Viscosity Loss, 40 C, %, ASTM D5621 21
Sodium, ppm, ICPES 1
Specific Gravity, 25 C/25 C, ASTM D4052 0.997
Specific Heat Capacity, cal/g-deg.C, Reference 0.42
Sulfur, ppm, ICPES/XRF 51
Thermal Conductivity at 40 C, cal/cm-sec-deg.C, Reference 33×10^-5 (0.0799)
Viscosity Index, ASTM D2270 280
Water Content, mass%, ASTM D6304 0.09
Pour Point, °F, ASTM D97 / ASTM D5950 -80
NAS 1638 Class, HIAC, ISO 11500 7

Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @


It cannot be guaranteed that the product information given above is up to date. For the latest version of the Product Data Sheet we refer to the product library of ExxonMobil.