Product description

For many years MIL-PRF-23699 approved engine lubricants were employed in helicopter gearboxes, ensuring a common lubricant for both engines and transmission systems. More recently, high-load-carrying oils have been evaluated and found to offer advantages over conventional-load-carrying MIL-PRF-23699 oils. These higher-load-carrying oils, complying with specification DOD-PRF-85734, were originally intended only for engine applications. The two MIL spec oils are thus of identical viscometric properties. Operators considered that lubrication performance of gearboxes could be enhanced by a higher-viscosity, high-load-carrying lubricant possessing improved corrosion-protective qualities.

Eastman HALO 157™ is a clear, amber-colored fluid with a faintly aromatic odor reminiscent of turbine engine oils. It is based on selected polyol esters, the inherent characteristics of which are enhanced by additives. It is also fully compatible and miscible with other oils approved to specifications MIL-PRF-23699 and MIL-PRF-7808.

Multiple tests have been completed in bearing and gearbox rigs and flight evaluations, culminating in the NATO standard (AIR STANDARD ACS 4035) for a 9-cSt advanced helicopter gearbox lubricant.


  • Aviation turbine oil (ATO)
  • Helicopter oil

    Key attributes

    • A purpose designed lubricant with a viscosity of 9 cSt @ 100ºC and 12,700 cSt @ -32ºC
    • Excellent load carrying and antiwear performance
    • Excellent shear stability
    • Good corrosion resistance
    • Good elastomer compatibility
    • Greater inter-gear film thickness
    • High temperature stability

      Regulatory information and data sheets

      Product availability

      Check with local sales office to determine exact availability by country. Orders subjected to minimum order quantity.
      • Asia Pacific
      • Europe, Middle East, & Africa
      • Latin America
      • North America

      Authorized distributors

      Please select a region and country for a list of authorized distributors. If a country is not listed for a region, contact Eastman for further information.
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