MIL-PRF-7808 describes the composition, performance, and compatibility requirements for aircraft turbine engine lubricating oil, intended for use in specific models of helicopter transmissions, aircraft turbine engines, accessory and auxiliary power units, and other types of equipment.

MIL-PRF-7808 covers two grades of synthetic base oil:
  • Grade 3: Suitable for most applications
  • Grade 4: Suitable for applications that call for higher viscosity or greater thermal stability.
While the spec was written for original lubricating oils, reblend and rebrand lubricating oils may also be approved via a process described in section 6.3 of the spec.

MIL-PRF-7808 details the requirements for a comprehensive list of performance attributes other parameters for aircraft turbine engine lubricating oils, including:
  • Particulate contamination
  • Viscosity at multiple temperatures
  • Flash point
  • Evaporation loss
  • Static and dynamic foaming
  • Deposition
  • Lead, silver, and bronze corrosion
  • Thermal stability
  • Shear stability
  • Storage stability
  • Trace amounts of ten different metals
  • Load carrying capacity
The specification lists the ASTM or FED-STD documents where methods for each test can be found. For test methods that require the use of ozone-depleting chemicals, the spec provides acceptable substitutes. 

How Smithers Supports MIL-PRF-7808

Smithers supports qualification and performance assessment for materials and components exposed to aircraft turbine engine lubricants through independent testing, technical assessment, and fluid compatibility evaluation. Our specialists help organizations understand how lubricants interact with polymer and elastomer materials under representative service conditions, supporting material selection, qualification, and long-term durability. 

Explore our Defense Materials and Qualification capabilities to learn more.

MIL-PRF-7808 provides a framework for qualifying aircraft turbine engine lubricants and verifying their performance under demanding operating conditions. The specification supports reliable material and lubricant performance across a wide range of defense aerospace applications.
 

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