Mobil™ HyJet™ IV-Aplus

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Engineered for use in commercial and business aircraft, Mobil HyJet IV-Aplus is the hydraulic fluid of choice for many of today’s mixed-fleet airlines.

Mobil HyJet IV-Aplus is a fire-resistant Type IV phosphate ester aviation hydraulic fluid that offers performance capabilities at levels close to those of Type V fluids. Mobil HyJet IV-Aplus hydraulic fluid offers outstanding rust and deposit control. The lowest density Type IV fluid commercially available today, Mobil HyJet IV-Aplus hydraulic fluid can help airlines save money.

Reasons to trust in Mobil HyJet IV-Aplus hydraulic fluid

  1. Offers potential savings in fuel consumption and costs with its low-density formulation
  2. Provides excellent high-temperature stability and low-temperature viscosity for extended fluid and component life
  3. Offers superb deposit control and exceptional protection against wear, rust and corrosion, helping airlines reduce repair costs and maximize equipment life
  4. Carries wide range of aircraft manufacturer approvals to offer greater flexibility to operators 

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Product information

   Mobil™ HyJet™ IV-Aplus performance profile 1.561 MB/pdf
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Features and benefits

Mobil HyJet IV-Aplus offers the following key features and benefits:
Advantages and potential benefits
Best in high temperature stability among Type IV fluids Longer fluid life.Lesser need to replace fluid due to degradation.Reduced hydraulic system maintenance costs
Lowest density Type IV fluid Reduced weight of the hydraulic fluid carried by aircraft.Reduced aircraft fuel consumption, lower operating costs
Effective rust protection Reduced the risk of equipment damage in the event of major water contamination
Excellent low temperature flow (viscosity) properties Precise hydraulic system control and response even during extended range/polar flights.Longer equipment life
Excellent deposit control Longer equipment life.Reduced maintenance costs
Excellent protection against electro-chemical corrosion (erosion) Protection against servo valve and pump damage
Approved by all major aircraft manufacturers Use as fleet lubricant by airline operators
Fully compatible with all approved phosphate ester hydraulic fluids Flexibility in use by airline operators


Mobil HyJet IV-Aplus fire-resistant aviation hydraulic fluid is used in commercial aircraft hydraulic systems where phosphate hydraulic fluids are recommended. It is compatible in all proportions with commercial Type IV and Type V phosphate ester aviation hydraulic fluids.

Mobil HyJet IV-Aplus meets or exceeds the following industry and aircraft builder specifications. It is approved against all commercial aircraft manufacturer requirements and is included in their Qualified Products Lists.

Specifications and approvals

Mobil HyJet IV-Aplus
Meets Type IV, Low density
Is in Qualified Products List
SAE Aerospace Standard AS1241C X Not Applicable
Airbus NSA307110N X X
ATR NSA307110N X X
Boeing BMS 3-11P, Type IV, Grade B and Grade C X X
Boeing (Douglas Division) DMS 2014H, Type 4 X X
British Aerospace (Avro) BAC.M.333C X X
Bombardier/Canadair BAMS 564-003A X X
Bombardier/DeHavilland X X
Cessna X X
Embraer X X
Fokker X X
Gulfstream Aerospace 1159SCH302J X X
Lockheed C-34-1224C X X

Typical properties

Test Method
Mobil HyJet IV-Aplus (1)
Kinematic Viscosity, cSt ASTM D 445

at -53.9ºC (-65ºF)

1320 2000 max
at -26.1ºC (-15ºF)

130 135 max
at 37.8ºC (100ºF)

10.6 10.0 -11.0
at 98.9ºC (210ºF)

3.6 3.35 - 3.75
at 127.6ºC (260ºF)

2.6 1.5 min
Viscosity Index ASTM D 2270 280

Shear Stability, % Viscosity Drop at 40ºC ASTM D 5621 22

Pour Point, ºC (ºF) ASTM D 97 ‹-62 (-80) -62 (-80) max
Specific gravity at 25ºC/25ºC (77ºF/77ºF) ASTM D 4052 0.996 0.990 -1.002
Density at 15.6ºC (60ºF), g/mL (lb/gal) ASTM D 4052 0.999 (8.35)

Acid Number, mg KOH/g ASTM D 974 0.04 0.1 max
Water, Karl Fischer, mass % ASTM D 6304 0.1 0.2 max

Flash Point, ºC (ºF) ASTM D 92 176 (349) 160 (320) min
Fire Point, ºC (ºF) ASTM D 92 188 (370) 177 (350) min
Autoignition Point, ºC (ºF) ASTM D 2155 ›427 (800) 400 (752) min
Foaming Tendency/Stability, mL foam/sec to collapse ASTM D 892

Sequence I

27/15 250/100 max
Sequence II

23/13 150/50 max
Sequence III

28/16 450/250 max
Particle count, NAS 1638 Class Auto Counter 4 7 max
Chemical Elements, ppm


103 120 max

38 48 max

10 50 max

1 15 max

224 350 max
Four-Ball Wear, Scar diameter at 75ºC/600rpm/1hour, mm Modified ASTM D 4172

4 kg

0.22 0.45 max
10 kg

0.33 0.50 max
40 kg

0.73 0.55 – 0.85
Electrical Conductivity at 20ºC, microSiemens/cm

1.4 0.5 min
Bulk Modulus, Isothermal secant at 100ºF/3000 psi, psi


Thermal Conductivity at 40ºC, cal/sec/cm2/ºC (Btu/hr/ft2/ºF)

33x10^-5 (0.0799)

Coefficient of thermal expansion, 25 to 100ºC, per ºC (per ºF)

0.00086 (0.00048)

Specific heat capacity at 40 ºC, cal/g/ºC (same as Btu/lb/ºF)


(1) Values may vary within modest ranges  


Mobil HyJet IV-Aplus
  • Airbus
  • BAE/Avro
  • Boeing
  • Bombardier
  • Bombardier/Canadair
  • Bombardier/de Havilland
  • Cessna
  • Embraer
  • Fokker
  • Gulfstream
  • Lockheed Martin
  • Liyushin (IL-86 and 96)
  • Mitsubishi
  • High temperature stability
  • Maximize component life
  • Extended fluid life
  • Low density
  • Rust protection
  • Deposit control
  • Erosion protection
  • Corrosion protection
  • Fire-resistance
  • Resists degradation
  • SAE Aerospace Standard AS1241C Type IV
  • Airbus / ATR NSA 307110N
  • Boeing BMS 3-11P, Type IV, Class 1 and Type V, Grade B and Grade C Â
  • Boeing (Douglas Division) DMS 2014H Type IV
  • British Aerospace (Avro) BAC.M.333C
  • Bombardier/Canadair BAMS 564-003A
  • Gulfstream Aerospace 1159SCH302J
  • Lockheed C-34-1224C
  • Type IV
  • Exxcare hydraulic systems oil analysis

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