WIth the need to transmit more power and higher loads through helicopter transmission and gearbox systems (many helicopters use a synthetic turbine engine oil in the transmission/gearbox system), it has become apparent that the use of a very good load carrying oil, such as AeroShell Turbine Oil 555 is necessary. This in turn has led to the development of a U.S. Military Specification, DOD-PRF-85734, which covers a helicopter transmission oil against which AeroShell Turbine Oil 555 is fully approved. AeroShell Turbine Oil 555 contains a synthetic ester oil and should not be used in contact with incompatible seal materials, and it also affects some paints and plastics.
