This standard is supplementary to AS 41 'Propeller Shaft Ends, Single Rotation', and AS 91 'Propeller Shaft Ends, Dual Rotation (Propeller Supplied Bearing)'. It is applicable to all engines that incorporate two-speed propeller reduction gears.
SAE AS178-1995 history
1995SAE AS178-1995 Two-Speed Propeller Reduction Gear Control
1945SAE AS178-1945 Two-Speed Propeller Reduction Gear Control