Every aircraft relies on hydraulic systems to perform critical functions safely and efficiently. From extending the landing gear during approach to controlling flight surfaces and operating braking systems, hydraulic fluid plays a vital role in ensuring dependable aircraft operation.
Unlike conventional hydraulic oils used in industrial machinery, aviation hydraulic fluids must perform under demanding conditions. They are expected to maintain consistent viscosity across a wide temperature range, resist oxidation, protect sensitive hydraulic components from wear and corrosion, and deliver reliable performance at both high altitudes and elevated operating temperatures.
One of the most widely recognised hydraulic fluids in the aviation industry is AeroShell® Fluid 31. Developed by Shell Aviation, this synthetic hydrocarbon-based hydraulic fluid has been trusted by commercial airlines, military operators, helicopter fleets and maintenance organisations worldwide for decades. Its excellent low-temperature characteristics, oxidation stability and broad OEM approvals make it a preferred choice for many aircraft hydraulic systems.
AeroShell® Fluid 31 is a synthetic hydrocarbon-based aviation hydraulic fluid designed for aircraft hydraulic systems operating under demanding environmental and operational conditions.
It is formulated to meet the requirements of MIL-PRF-83282, a military performance specification for fire-resistant hydraulic fluids used in aircraft hydraulic systems. Compared with older mineral-based hydraulic fluids, AeroShell Fluid 31 offers improved thermal stability, better wear protection and enhanced fire resistance.
Its excellent performance characteristics make it suitable for numerous commercial, military and helicopter applications where approved by the aircraft or equipment manufacturer.
Aircraft Hydraulic Fluid → Synthetic Hydrocarbon Hydraulic Fluid → Fire-Resistant Aviation Hydraulic Fluid
MIL-PRF-83282
H-537
Aircraft hydraulic fluids are manufactured according to strict military and aerospace specifications to ensure safe and reliable operation.
MIL-PRF-83282 specifies synthetic hydrocarbon hydraulic fluids designed to provide:
Compared with older MIL-PRF-5606 fluids, products meeting MIL-PRF-83282 generally offer higher flash points and improved performance in high-temperature environments.
Hydraulic system reliability directly affects aircraft safety and operational efficiency.
AeroShell Fluid 31 has earned its reputation through years of dependable performance across commercial aviation, military aircraft and rotorcraft operations. Its combination of low-temperature fluidity, thermal stability and wear protection helps operators maintain hydraulic system reliability while supporting extended maintenance intervals.
Aircraft frequently operate in extremely cold environments, particularly at cruising altitude.
AeroShell Fluid 31 remains sufficiently fluid at very low temperatures, allowing hydraulic systems to respond quickly during engine start-up and flight operations.
Exposure to heat and oxygen gradually causes hydraulic fluids to degrade.
AeroShell Fluid 31 resists oxidation, helping reduce sludge formation and maintain clean hydraulic systems throughout its service life.
Aircraft hydraulic pumps, valves and actuators operate under high pressure.
AeroShell Fluid 31 provides a durable lubricating film that helps reduce component wear and supports long-term hydraulic system reliability.
Moisture and contaminants can contribute to corrosion within hydraulic systems.
Specially formulated additives help protect metal components against corrosion, improving system durability.
Compared with older aviation hydraulic fluids, AeroShell Fluid 31 offers a significantly higher flash point, providing improved resistance to ignition in high-temperature operating environments.
Its resistance to oxidation, thermal degradation and wear enables AeroShell Fluid 31 to deliver consistent hydraulic performance throughout recommended maintenance intervals.
AeroShell Fluid 31 is commonly used in:
Depending on OEM approval and maintenance documentation, AeroShell Fluid 31 may be used in hydraulic systems associated with:
Always consult the applicable Aircraft Maintenance Manual (AMM) or Component Maintenance Manual (CMM) before selecting a hydraulic fluid.
Several aviation hydraulic fluids are available for different aircraft applications.
Some recognised products include:
| Brand | Product |
|---|---|
|
Shell |
AeroShell Fluid 31 |
|
Eastman |
Skydrol LD-4* |
|
Eastman |
Skydrol 5 |
|
ExxonMobil |
HyJet IV-Aplus |
|
Royco |
Royco 782 |
Skydrol products are phosphate ester hydraulic fluids and are designed for different aircraft systems. Always follow OEM-approved specifications before selecting a hydraulic fluid
Aircraft hydraulic fluids are not universally interchangeable.
Different aircraft systems are designed for specific hydraulic fluid chemistries and specifications. Using the incorrect hydraulic fluid may damage seals, reduce system performance and create maintenance issues.
Hydraulic fluid selection should always follow:
Never substitute hydraulic fluids based solely on availability or price.
Selecting an approved aviation hydraulic fluid helps support:
Proper hydraulic fluid selection contributes directly to aircraft safety, operational efficiency and long-term reliability.
AeroShell Fluid 31 is a synthetic hydrocarbon aviation hydraulic fluid designed for aircraft hydraulic systems operating under demanding commercial, military and helicopter applications
AeroShell Fluid 31 is formulated to meet MIL-PRF-83282, a military specification for high-performance aviation hydraulic fluids.
Some aircraft manufacturers permit conversion procedures between approved hydraulic fluids, while others do not. Always follow the aircraft manufacturer's maintenance documentation before changing hydraulic fluid types.
Yes. AeroShell Fluid 31 is widely used in helicopter hydraulic systems where approved by the helicopter or equipment manufacturer.
Compared with older mineral-based hydraulic fluids such as MIL-PRF-5606 fluids, AeroShell Fluid 31 provides significantly improved fire resistance due to its higher flash point.
Favia supplies genuine aviation hydraulic fluids, lubricants and aircraft consumables to airlines, helicopter operators, MRO facilities, defence organisations and industrial customers throughout the Middle East and international markets.
Our experienced team assists customers in selecting approved aviation hydraulic fluids based on aircraft type, hydraulic system specification and OEM maintenance documentation.
Whether you require scheduled maintenance stock, urgent AOG support or long-term procurement solutions, Favia delivers authentic aviation products backed by responsive customer service and dependable global logistics.
© 2008-2025 Favia International. All rights Reserved.
