What type of engine oil is specified for use?

The specified engine oil for the MH-60S is MIL-PRF-23699, which is a military specification for lubricating oils used in aircraft engines. This particular type of oil is designed to meet the stringent requirements of high-performance aircraft, providing necessary properties such as thermal stability, low temperature fluidity, and enhanced lubricating qualities.

MIL-PRF-23699 is formulated to withstand the extreme conditions encountered in aerospace environments, ensuring that the engine operates efficiently and reliably. Its properties help to reduce wear, protect against corrosion, and maintain engine performance over a range of temperatures, which is critical for the operational readiness of military helicopters like the MH-60S.

The other types of oils mentioned, such as API SN and SAE 10W-30, are primarily used in automotive engines and may not provide the necessary performance needed for military aircraft. ISO 68 refers to a viscosity grade rather than a specification for aviation applications, making it unsuitable for use in the MH-60S engine.