Mobil Aero HFA
Mineral hydraulic fluid for older aircraft, to MIL-H-5606A, down to −54 °C
Business customers only. We sell wholesale, invoiced to registered companies.
Standards & approvals
MIL-H-5606A
MIL-H-5606A — aviation hydraulic fluid
Earlier issue of the US military red mineral hydraulic fluid specification; continued as MIL-PRF-5606.
Specifications
- Brand
- Mobil (ExxonMobil)
- Range
- Mobil Aero
- Category
- Aviation hydraulic fluids
- Manufacturer code
- 201550401020
- Availability
- On request
Typical characteristics
| Property | Typical value | Method |
|---|---|---|
| API gravity°API | 30 | ASTM D287 |
| Acid numbermgKOH/g | 0.03 (0.2 max) | ASTM D664 |
| Bulk Modulus, Isothermal secant at 40 C/4000 psipsi | 200,000 min | ASTM D6793 |
| Colour | Red | Visual |
| Copper strip corrosion, 72 hrs at 135 C | 1B (2E max) | ASTM D130 |
| Corrosion and Oxidation stability, 168 hours at 135 CRating | PASS | ASTM D4636 |
| Density @ 60 F, lb/gal | 7.26 | CALCULATED |
| Flash point, Cleveland Open Cup°C | 107 (93 min) | ASTM D92 |
| Flash point, Pensky-Martens Closed Cup°C | 92 | ASTM D93 |
| Foam, Sequence I, Stabilityml | 0 | ASTM D892 |
| Foam, Sequence I, Tendencyml | 36 (65 max) | ASTM D892 |
| Four-Ball Wear Test, Scar Diameter, 40 kg, 1200 rpm, 1 h, 75 Cmm | 0.6 (1.0 max) | ASTM D4172 |
| Kinematic viscosity -40 FcSt | 450 (500 max) | ASTM D445 |
| Kinematic viscosity 130 FcSt | 10.4 (10.0 min) | ASTM D445 |
| Kinematic viscosity @ -54 Cmm2/s | 1900 | ASTM D445 |
| Kinematic viscosity @ 100 Cmm2/s | 5.2 | ASTM D445 |
| Kinematic viscosity @ 40 Cmm2/s | 14.0 | ASTM D445 |
| Low temperature stability, 72 hrs @ - 54 C | PASS | FTM 3459 |
| Pour point°C | -64 (-60 max) | ASTM D97 |
| Specific gravity 60 F / 60 F | 0.872 | ASTM D4052 |
| Viscosity index | 370 | ASTM D2270 |
| Water, Karl-Fischerppm | 50 (100 max) | ASTM D1744 |
Complete documentation

Manufacturer's description
Mobil Aero HFA is the MIL-H-5606A grade of the Mobil Aero HF Series, a low-viscosity, high-viscosity-index hydraulic fluid formulated for aircraft systems where hydrocarbon-based hydraulic fluids are required. Composed of mineral base oil with shear-stable VI improvers, it offers excellent low-temperature properties, good anti-wear performance and good chemical stability. Mobil Aero HFA meets the quality requirements of the (now obsolete) U.S. Military specification MIL-H-5606A and is suitable for use at temperatures down to -54 °C. It is no longer used by the U.S. Military but is still found in some older, small private and commercial aircraft, and in industrial and commercial equipment requiring good fluidity at very low temperatures. It offers a very high viscosity index for wide-temperature-range operation and good chemical and oxidation stability, resisting acidic by-products, varnish and deposit formation, ensuring reliable performance of pumps, servo-valves and other hydraulic system components. Typical properties: kinematic viscosity 14.0 mm²/s at 40 °C and 5.2 mm²/s at 100 °C, pour point -64 °C.
Applications
- Mobil Aero HFA is a premium-quality fluid that meets the quality requirements of the U.S. Military specification MIL-H-5606A (now obsolete); it has a very high VI and is suitable for use at temperatures down to -54°C (-65°F).
- While no longer used by the U.S. Military, Mobil Aero HFA is still used in some older, small private and commercial aircraft, as well as in industrial and commercial equipment requiring good fluidity at very low temperatures, providing long, trouble-free service over a wide range of operating conditions.
- Mobil Aero HF is a premium-quality fluid approved against the most current version of U.S. Military specification MIL-PRF-5606; it has physical properties very similar to Mobil Aero HFA and also meets the 'super-clean' requirements of modern aircraft hydraulic systems.
- It is intended primarily for military aircraft, but is also used as a hydraulic fluid for small private and commercial aircraft, and as a strut fluid in the landing gear of large commercial aircraft; it is a NATO Code Number H-515 fluid.
Performance & benefits
- High Viscosity Index (VI) — allows equipment operation over a wide range of temperatures.
- Excellent low-temperature properties — provides high-performance operation in low ambient conditions.
- Good chemical and oxidation stability — resists the formation of acidic constituents, varnishes and deposits.
- Meets the 'super clean' requirements of U.S. Spec. MIL-PRF-5606 (Aero HF) — ensures reliable performance of pumps, servo-valves and other hydraulic system components.
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