Royco 756 Hydraulic Fluid, MIL-PRF-5606

Royco 756 is a red-dyed, mineral oil-based aviation hydraulic fluid formulated for severe-duty aerospace and industrial applications. Manufactured by LANXESS, Royco 756 provides low-temperature fluidity, anti-wear protection, oxidation and corrosion resistance, and shear stability.

Royco 756 is qualified to MIL-PRF-5606J and is identified by NATO Code H-515 and military symbol OHA. It is commonly used in aircraft hydraulic systems, autopilots, shock absorbers, missile systems, and other equipment requiring a petroleum-base hydraulic fluid meeting the applicable MIL-PRF-5606 requirements.

Royco 756 Hydraulic Fluid Specifications

Key Features of Royco 756

• Petroleum-base formulation designed for aviation hydraulic applications.
• Excellent low-temperature fluidity for hydraulic systems operating in cold environments.
• Anti-wear protection to help protect hydraulic-system components.
• Oxidation and corrosion inhibition for demanding hydraulic service.
• Shear stability for severe-duty applications.
• Metal deactivators to help protect system components.
• Foam inhibitors for hydraulic-system performance.
• High viscosity index for performance across a broad temperature range.
• "Super Clean" formulation for applications where hydraulic-fluid cleanliness can contribute to component life and reliability.

Applications for Royco 756

Royco 756 is designed for aerospace and industrial hydraulic applications requiring a petroleum-base hydraulic fluid meeting the applicable MIL-PRF-5606 requirements.

• Aircraft hydraulic systems
• Aircraft autopilot systems
• Landing gear shock absorbers
• Aircraft brake systems
• Missile hydraulic systems
• Hydraulic flap-control mechanisms
• Industrial hydraulic equipment
• Cherry pickers and boom trucks
• Hydraulic robotic equipment

Always verify the required hydraulic-fluid specification against the applicable aircraft maintenance manual, component maintenance manual, equipment manufacturer's documentation, or other controlling technical documentation.

Royco 756 Technical Data

Typical values are provided for technical reference and are not specification limits. Refer to the current LANXESS Technical Data Sheet for applicable specification requirements and current product data.

MIL-PRF-5606 Hydraulic Fluid

MIL-PRF-5606 covers petroleum-base hydraulic fluid for aircraft, missile, and ordnance applications. The specification identifies the fluid by NATO Code H-515 and military symbol OHA.

LANXESS currently identifies Royco 756 as qualified to MIL-PRF-5606J, which supersedes MIL-PRF-5606H(3). Older aircraft and maintenance documentation may reference earlier revisions or the former MIL-H-5606 designation. When a maintenance document specifies a particular revision, always verify the exact requirement before selecting the fluid.

DLA's current ASSIST record identifies the MIL-PRF-5606 document as inactive, while the LANXESS product documentation continues to identify Royco 756 as qualified to MIL-PRF-5606J. For procurement or revision-controlled applications, use the specification and revision identified by the applicable equipment documentation and the manufacturer's current qualification documentation.

Royco 756 vs. Royco 782

Royco 756 and Royco 782 are both aviation hydraulic fluids, but they use different base-fluid chemistries and are qualified to different military specifications.

The two fluids should not be selected based solely on color or general application. Use the hydraulic-fluid specification identified by the aircraft or component manufacturer.

Temperature Range

LANXESS specifies Royco 756 for use in unpressurized systems from -54°C to 90°C (-65°F to 195°F) and in pressurized systems from -54°C to 135°C (-65°F to 275°F), at pressures up to 3,000 psi.

These application ranges should not be interpreted as universal limits for every aircraft or component. The aircraft or equipment manufacturer's approved operating limits and fluid requirements control.

Compatibility and Seal Materials

Royco 756 is a petroleum/mineral oil-based hydraulic fluid intended for systems designed for this type of fluid. LANXESS specifically states that Royco 756 and Royco 756A should not be used in systems using natural rubber seals.

Before changing hydraulic-fluid types, verify seal compatibility and the fluid requirements specified by the aircraft, component, or equipment manufacturer.

Shelf Life and Storage

Current LANXESS product literature lists a 4-year commercial shelf life for Royco 756. Military and NATO packaging may have different shelf-life requirements.

Store the product in accordance with the manufacturer's current storage recommendations and keep containers properly closed when not in use. For lot-specific shelf-life information, use the date and documentation supplied with the product.

Royco 756 Documentation

Aircraft maintenance and MRO customers may require documentation identifying the product specification, revision, lot, and release. Product documentation may include:

• Technical Data Sheet (TDS)
• Safety Data Sheet (SDS)
• Certificate of Conformance (CofC), when applicable
• Lot and date-of-manufacture information

If a specific MIL-PRF-5606 revision or release is required, identify that requirement when ordering so the applicable product documentation can be verified.

Ordering Royco 756 Hydraulic Fluid

Business Aircraft Consumables stocks Royco 756 hydraulic fluid in multiple package sizes for aircraft maintenance, MRO, military, and industrial applications requiring MIL-PRF-5606 hydraulic fluid.

For assistance confirming the required specification, package size, or documentation for your order, contact Business Aircraft Consumables at 888-239-6625, Monday through Friday, 8:00 AM–5:00 PM CST.

Frequently Asked Questions About Royco 756

Related Aviation Hydraulic Fluids

Business Aircraft Consumables also supplies Royco 782, Skydrol, HyJet, AeroShell, and other aviation hydraulic fluids. Always select hydraulic fluid according to the specification and approvals required by the applicable aircraft or component documentation.

Important: Aviation hydraulic fluids are not universally interchangeable. Always verify the aircraft, component, or equipment manufacturer's approved hydraulic-fluid specification before selecting or replacing a fluid. Refer to the current manufacturer Technical Data Sheet and Safety Data Sheet for detailed technical, handling, compatibility, and storage information.