Historical
SAE ARP 246C-2001 (SAE ARP246C-2001)
Orientation of Engine Axis, Coordinate and Numbering Systems for Aircraft Gas Turbine Engines ( Reaffirmed: May 2006 )
To establish an orientation standard for aircraft gas turbine engines and their component parts. Orientation of the engine, engine axis and coordinate system referred to herein shall be the conventional terminology used in all references to aircraft gas turbine engines. Numbering as provided herein is intended for convenience in locating a particular unit in a group of like or similar units.
Society of Automotive Engineers [sae]