AeroShell Fluid 31 - 1 Gallon

AeroShell Fluid 31 is a synthetic, low-viscosity hydraulic fluid formulated for advanced aircraft hydraulic systems that require exceptional stability and reliability. Built on high-quality synthetic hydrocarbon base oils with a specialized additive blend, it delivers strong low-temperature capability, oxidation resistance, and wear protection. Due to its ability to maintain performance under high pressure and thermal stress, it is widely used in commercial, military, and high-performance aircraft. Its extremely clean formulation also supports the precision operation of modern hydraulic components.

AeroShell Fluid 31 is commonly used in hydraulic circuits that operate landing gear, primary and secondary flight controls, thrust reverser systems, and aircraft braking systems. Its robust anti-wear characteristics help protect pumps, actuators, and valves from premature wear, even in high-pressure environments. The fluid’s excellent thermal and oxidative stability ensures responsive, consistent performance in both hot and cold operating conditions. This makes it a preferred option for operators flying in diverse climates or requiring highly dependable hydraulic performance.

AeroShell Fluid 31 is based on synthetic hydrocarbon oils known as polyalphaolefins (PAOs). These base oils offer superior thermal stability, consistent viscosity across a wide temperature range, and cleaner performance compared to traditional mineral oils. The formulation minimizes evaporation, resists deposit formation, and enhances fluid longevity. Its PAO foundation is a key contributor to the fluid’s long service life and excellent system cleanliness.

AeroShell Fluid 31 is designed to perform reliably over a temperature range of approximately -40°F to 401°F (-40°C to 205°C). This broad range ensures excellent fluidity during cold-weather starts as well as stability during high-temperature operations. Even in extreme cold, it maintains flow characteristics that support actuator responsiveness and pump protection. At elevated temperatures, the synthetic formulation helps prevent viscosity loss and thermal degradation.

Unlike MIL-PRF-5606 fluids, which are mineral-based, AeroShell Fluid 31 uses a synthetic PAO base designed for enhanced thermal stability and extended high-temperature performance. It also delivers greater fire resistance, helping improve safety in environments where heat and pressure are significant concerns. Additionally, its oxidation resistance is far superior to 5606 fluid, reducing sludge and varnish buildup. Many operators transition to Fluid 31 to achieve longer fluid life, increased safety margins, and improved cold-weather performance.

AeroShell Fluid 31 offers enhanced fire resistance compared to traditional mineral-oil hydraulic fluids, such as MIL-PRF-5606. Its synthetic base elevates the flash point and reduces the likelihood of ignition in the event of leaks or exposure to high temperatures. Although it is not as fire-resistant as phosphate-ester fluids, it offers a meaningful safety advantage for many aircraft platforms. This elevated fire resistance contributes to its widespread use in modern aviation.

AeroShell Fluid 31 is formulated to be compatible with most commonly used aircraft hydraulic seal materials, including nitrile and fluorocarbon elastomers. Its chemistry helps minimize swelling, shrinking, or hardening of seals when used within approved systems. Even so, operators should always confirm compatibility through OEM documentation or maintenance manuals. Ensuring proper material matching helps extend seal life and reduce the potential for leaks.

Mixing AeroShell Fluid 31 with other hydraulic fluids – especially mineral or phosphate-ester types – is not recommended unless specifically approved by the aircraft manufacturer. Differences in chemistry can compromise additive performance, alter viscosity, or reduce the fluid’s fire-resistant properties. When converting systems to Fluid 31, a full flush is generally advised to remove prior fluid residues. This ensures optimum performance and predictable system behavior.

AeroShell Fluid 31 provides outstanding low-temperature flow, making it highly effective for cold-climate operations and high-altitude flight. Its synthetic formulation helps protect components from wear, corrosion, and deposit buildup, extending the life of pumps, actuators, and valves. The fluid’s resistance to oxidation and thermal breakdown reduces maintenance demands, supporting cleaner hydraulic systems overall. Combined, these advantages make it a reliable choice for operators who require consistent and long-lasting hydraulic performance.

AeroShell Fluid 31 is widely used across commercial jet fleets, turboprops, business aircraft, and military platforms that require a synthetic, low-viscosity hydraulic fluid. It is especially common on aircraft designed for harsh or variable environments, due to its broad temperature tolerance and safety profile. Many OEMs approve or recommend Fluid 31 for systems that demand high performance and low contamination levels. This broad compatibility makes it one of the most widely adopted synthetic hydraulic fluids in the aviation industry.

The fluid maintains excellent low-temperature fluidity, ensuring responsive system performance during cold starts and at high altitudes. Unlike some mineral oils that thicken in frigid conditions, Fluid 31 maintains a stable viscosity, supporting efficient actuator and pump operation. As a result, aircraft operating in northern or high-elevation environments benefit from reliable hydraulic response and reduced risk of sluggish components.

Yes. AeroShell Fluid 31 is engineered for excellent oxidation resistance, minimizing the formation of varnish, sludge, and deposits during extended service. Its synthetic PAO base helps it withstand high temperatures and prolonged system stress without degrading. Maintaining hydraulic cleanliness and fluid stability contributes to longer service intervals and reduced component wear.

While actual service life depends on aircraft type, operating conditions, and maintenance practices, AeroShell Fluid 31 typically lasts longer than mineral-oil hydraulic fluids. Its resistance to oxidation slows degradation, allowing the fluid to remain usable for extended periods between changes. Routine fluid analysis is recommended to monitor contamination levels and ensure continued performance. Many operators find that Fluid 31 reduces maintenance frequency and improves long-term hydraulic reliability.

AeroShell Fluid 31 should be handled with standard safety precautions. Avoid prolonged skin or eye contact, and always use protective gloves and eyewear when servicing hydraulic systems. Work in well-ventilated areas to reduce exposure to mist or vapor. Refer to the Safety Data Sheet (SDS) for comprehensive guidance on handling, storage, and first aid.

Store AeroShell Fluid 31 in sealed containers in a clean, dry environment away from sunlight and extreme temperatures. Proper storage prevents moisture intrusion and contamination, helping preserve the fluid’s stability and performance characteristics. Keeping containers tightly closed when not in use ensures the product remains within specification until it is needed. Always follow manufacturer recommendations for long-term storage and shelf-life management.

AeroShell Fluid 31 has a recommended shelf life of three years. This shelf life assumes that the product is stored in its original unopened container at ambient temperature conditions.