This document contains the Minimum Operational Performance Standard for On Board Weight and Balance Systems for Large Aeroplanes (CS-25). These standards specify the minimum performance expected from such an On Board Weight and Balance System. Compliance with this standard is recommended as one means of assuring that the equipment will perform its intended function(s) satisfactory under all conditions normally encountered in routine aeronautical operation. This minimum operational performance standard is designed to ensure that equipment compliant to it will get the necessary regulatory approval (this is generally facilitated by the recognition of such standards by the relevant authorities as an acceptable means of compliance with the applicable regulations).