MIL-PRF-32538, PERFORMANCE SPECIFICATION: LUBRICATING OIL, HELICOPTER TRANSMISSION SYSTEM, SYNTHETIC BASE, NATO CODE NUMBER: O-165 (07-OCT-2015)

MIL-PRF-32538, PERFORMANCE SPECIFICATION: LUBRICATING OIL, HELICOPTER TRANSMISSION SYSTEM, SYNTHETIC BASE, NATO CODE NUMBER: O-165 (07-OCT-2015)., This specification covers the requirements for one grade of a synthetic base helicopter transmission system lubricating oil, which has a nominal viscosity of 9 mm²/s at 100 °C and which is typically made with neopentyl polyol ester base stocks. This oil is identified by NATO Code Number O-165.