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MIL-PRF-5606 is a military specification for hydraulic fluid. It outlines the requirements for hydraulic fluid used in aircraft systems, particularly in military aircraft. MIL-PRF-5606 stands for MIL - military, PRF- performance requirements, 5606 - unique identification number for the spec.

MIL-PRF-5606 Product list

These products either meet or are approved to the MIL-PRF-5606 specification. Please consult the product page and product description for the specific grade/size you intend to purchase to ensure it will be supplied with MIL-PRF-5606 paperwork.

Silmid P/N: 
No Stock - Standard lead time 24 business days
From £305.18 excl VAT
Silmid P/N: 
In Stock
From £18.09 excl VAT
Silmid P/N: 
In Stock
From £9.30 excl VAT
No Stock - Standard lead time 31 business days
From £303.01 excl VAT
Silmid P/N: 
No Stock - Standard lead time 45 business days
From £15.98 excl VAT


Composition: MIL-PRF-5606 specifies the composition of the hydraulic fluid, including the types and amounts of additives, lubricants, and other components. The fluid is typically petroleum-based and contains additives to enhance its lubricating and anti-corrosive properties.

Performance Requirements:
The specification sets forth various performance requirements that the hydraulic fluid must meet. This includes characteristics such as viscosity, flash point, pour point, corrosion resistance, and compatibility with materials commonly found in aircraft hydraulic systems.

Uses: The hydraulic fluid described in this specification is designed for application in automatic pilots, shock absorbers, brakes, flap-control mechanisms, missile hydraulic servo-controlled systems, and other hydraulic systems utilising synthetic sealing materials.

Interchangeability: This fluid demonstrates full compatibility with MIL-PRF-6083, MIL-PRF-46170, MIL-PRF-87257, and MIL-PRF-83282 hydraulic fluids. It can potentially serve as a substitute for these fluids in certain applications. The choice of which fluid to utilise depends on the specific demands of the operational system.


MIL-PRF-5606J - The most recent version of the spec, established in 2018.

MIL-PRF-5606H - Earlier version of the spec. First established in 2002 with 3 further amendments in 2003, 2005 and 2006.

MIL-PRF-5606 product tin