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MIL-PRF-87257

MIL-PRF-87257 is a military hydraulic fluid specification for aircraft and missiles. Fluids that meet the spec must satisfy requirements for viscosity, flash point, autoignition temperature, and other physical and chemical properties, and the fluid is identified by NATO Code H-538. For background on how these fluids work and how to choose between them, see our guide to aircraft hydraulic fluids.

MIL-PRF-87257 Product List

Please consult the product page and product description for the specific grade and size you intend to purchase, and confirm that it is supplied with MIL-PRF-87257 paperwork and the current revision letter before ordering.

Castrol Brayco Micronic 881 Hydraulic Fluid
Castrol Brayco Micronic 881 Hydraulic Fluid
Silmid P/N: 
VAR0000607
No Stock – Lead time 33 business days from date of order confirmation
From £19.35 excl VAT
View Details
Nyco Hydraunycoil FH 42
Nyco Hydraunycoil FH 42
Silmid P/N: 
VAR0000824
In Stock
From £31.06 excl VAT
View Details

List of Revisions

RevisionDetails
MIL-PRF-87257AEstablished Dec 1997, Superseding the previous spec, MIL-H-87257, where MIL = Military, H = Hydraulic fluid, 87257 = Unique identification number for this spec
MIL-PRF-87257BThis version superseded MIL-PRF-87257A in April 2004
MIL-PRF-87257CThis version of the spec was established in June 2017, superseding MIL-PRF-87257B
MIL-PRF-87257DThe most recent version of the spec. Established in February 2022

Key characteristics:

The points below summarize the spec traits buyers and engineers should check first when comparing MIL-PRF-87257 options.

  • Fire resistant: This is a critical property for aircraft and missile applications where flammability could be catastrophic

  • Temperature performance: The fluid is designed to function well in cold environments, down to -54°C. It has a wide temperature range, also withstanding +200°C at the upper level.

  • Synthetic hydrocarbon base: The fluid is made from synthetic materials derived from petroleum

  • Colour: MIL-PRF-87257 fluid is characterised by the colour red

  • Non-Aromatic: The fluid is non-aromatic, which contributes to lower toxicity and better environmental and health safety

  • Durability: Superior oxidative and thermal stability ensure long service life and reduce maintenance costs


Drum, can and tin, Nyco FH 42 packaging.

Summary

Manufacturers producing hydraulic fluids to meet MIL-PRF-87257 must undergo rigorous testing to ensure compliance with the specification. This includes testing for physical and chemical properties, as well as performance under simulated operational conditions. MIL-PRF-87257 sets the standard for high-performance hydraulic fluids used in demanding military applications. Its stringent requirements ensure that hydraulic systems remain operational under extreme temperatures, resist fire, and provide reliable performance in mission-critical scenarios.

MIL-PRF-87257 FAQs

How do I verify I am buying the correct MIL-PRF-87257 revision?

Check the revision history on the page and confirm that the product listing and paperwork match the revision you need before ordering. You can browse current stock on our hydraulic fluids category page.

What paperwork should accompany a compliant MIL-PRF-87257 product?

Buyers should confirm that the product page and supplied documents clearly show MIL-PRF-87257 compliance for the exact grade and size being purchased.

What should I check before using MIL-PRF-87257 in a sealed system?

Verify seal and elastomer suitability against OEM guidance before use, especially if the system is being converted from another hydraulic fluid such as MIL-PRF-83282 or MIL-PRF-5606.