Advanced helicopter transmission oil

For many years, MIL-PRF-23699-approved engine lubricants
have been employed in helicopter applications where
a common lubricant is required for both engines and
transmission systems.
Alternatively, high load-carrying engine oils also offer
advantages over conventional load-carrying MIL-PRF-23699
oils. Removing the 5-cSt constraints typical of engine oils,
optimal lubrication performance of gearboxes can be achieved
by using a higher-viscosity, high load-carrying lubricant with
other key features such as corrosion protection.
HALO 157 represents many years of research and
development using this approach and is the first advanced
helicopter transmission lubricant to meet the needs of the
new MIL-PRF-32528 specification.
HALO 157 is a 9-cSt, clear amber-colored fluid with a faintly
aromatic odor reminiscent of turbine engine oils. It is based
on selected polyol esters whose inherent characteristics are
enhanced by additives.