Skydrol LD-4 Hydraulic Fluid

Skydrol LD-4 is a low-density, fire-resistant Type IV phosphate ester hydraulic fluid manufactured by Eastman for aircraft hydraulic systems. It is formulated to provide excellent thermal stability, valve erosion protection, and deposit control in demanding aviation hydraulic applications.

Business Aircraft Consumables supplies Skydrol LD-4 in quart, gallon, and 5 gallon containers for aircraft maintenance, MRO, and hydraulic-system servicing.

Skydrol LD-4 Aircraft Hydraulic Fluid

Skydrol LD-4 is a Type IV phosphate ester aviation hydraulic fluid with a formulation developed specifically for aircraft hydraulic systems. Eastman introduced LD-4 in 1977 to address valve erosion and thermal-stability issues encountered with earlier hydraulic fluids. The formulation incorporates an anti-erosion additive and acid scavenger to help protect hydraulic-system components.

Its low-density formulation, thermal stability, valve erosion protection, and deposit-control characteristics make Skydrol LD-4 a widely used Type IV fluid for aviation hydraulic applications.

Skydrol LD-4 Features

• Type IV phosphate ester hydraulic fluid designed for aviation hydraulic applications.
• Low-density formulation developed for aircraft hydraulic systems.
• Excellent thermal stability for demanding operating conditions.
• Valve erosion protection provided by the formulation's anti-erosion additive.
• Deposit control to help maintain hydraulic-system cleanliness and component performance.
• Acid scavenger designed to help protect hydraulic-system components.
• Fire-resistant phosphate ester formulation intended for aircraft hydraulic applications.

Skydrol LD-4 Applications

Skydrol LD-4 is used as an aircraft hydraulic fluid in hydraulic systems requiring a Type IV phosphate ester fluid. Aircraft hydraulic systems can operate flight controls, landing gear, brakes, flaps, and other hydraulically powered equipment.

The correct hydraulic fluid must always be determined from the applicable aircraft maintenance manual, component maintenance manual, equipment manufacturer's documentation, or other approved technical source.

Skydrol LD-4 Technical Properties

Eastman's technical data sheet identifies the following typical properties for Skydrol LD-4. These values are provided for technical reference and should not be used in place of the manufacturer's current product documentation or applicable aircraft maintenance requirements.

Skydrol LD-4 Specifications and Approvals

Aircraft hydraulic-fluid requirements vary by airframe and hydraulic-system application. Skydrol LD-4 is associated with Type IV aircraft hydraulic-fluid requirements, including specifications used by major aircraft manufacturers.

Always verify the required specification and approval for the specific aircraft or component before ordering or installing hydraulic fluid. A product's general Type IV classification does not by itself establish approval for every aircraft or hydraulic-system application.

Skydrol LD-4 Shelf Life

Skydrol LD-4 has a stated shelf life of 3650 days when stored according to the manufacturer's requirements. BAC's current product listing identifies the same 3650-day shelf life.

For a specific container, always use the manufacturer's lot, date, labeling, and current technical documentation to determine the applicable expiration date.

Skydrol LD-4 Handling and Safety

Skydrol LD-4 is an industrial aviation hydraulic fluid and should be handled in accordance with the manufacturer's current Safety Data Sheet (SDS) and applicable workplace safety requirements.

The Eastman SDS identifies skin irritation as a hazard and includes additional hazard information and precautionary measures. Review the current SDS before handling the product and use the protective equipment specified by the manufacturer.

Skydrol LD-4 Documentation

Refer to the manufacturer's current documentation for complete technical and safety information:

• Skydrol LD-4 Technical Data Sheet (TDS)
• Skydrol LD-4 Safety Data Sheet (SDS)
• Current manufacturer sales specifications
• Applicable aircraft and component maintenance documentation

Ordering Skydrol LD-4

Business Aircraft Consumables supplies Skydrol LD-4 hydraulic fluid in quart, gallon, and 5 gallon containers for aircraft maintenance and MRO applications. Select the required container size above to check current availability and pricing.

For aircraft hydraulic-system servicing, always confirm the required fluid type, specification, and approved product against the applicable aircraft or component documentation before purchase or use.

Frequently Asked Questions

What is Skydrol LD-4?

Skydrol LD-4 is a low-density, fire-resistant Type IV phosphate ester hydraulic fluid manufactured by Eastman for aviation hydraulic applications. It is formulated for thermal stability, valve erosion protection, and deposit control.

What type of hydraulic fluid is Skydrol LD-4?

Skydrol LD-4 is a Type IV phosphate ester aviation hydraulic fluid.

What color is Skydrol LD-4?

Skydrol LD-4 is purple. Eastman's technical data sheet identifies its appearance as a clear, oily liquid with a purple color.

What is Skydrol LD-4 used for?

Skydrol LD-4 is used as an aviation hydraulic fluid in aircraft hydraulic systems designed for Type IV phosphate ester fluids. The aircraft or component manufacturer's documentation should always be consulted to confirm the required fluid.

What sizes of Skydrol LD-4 are available?

Business Aircraft Consumables offers Skydrol LD-4 in quart, gallon, and 5 gallon containers, subject to current availability.

How long is the shelf life of Skydrol LD-4?

The stated shelf life of Skydrol LD-4 is 3650 days when stored according to the manufacturer's requirements. Always verify the applicable shelf life using the product container and current manufacturer documentation.

Is Skydrol LD-4 fire resistant?

Yes. Skydrol LD-4 is a fire-resistant phosphate ester aviation hydraulic fluid designed for aircraft hydraulic applications.

Is Skydrol LD-4 interchangeable with other hydraulic fluids?

Hydraulic fluids should not be treated as universally interchangeable. Before mixing, replacing, or converting hydraulic fluids, verify compatibility and approval requirements in the applicable aircraft, component, or equipment manufacturer's documentation.