§25.29 Empty weight and corres- ponding centre of gravity

(a) The empty weight and corresponding centre of gravity must be determined by weighing the aeroplane with – (1) Fixed ballast; (2) Unusable fuel determined under CS 25.959; and (3) Full operating fluids, including – (i) Oil; (ii) Hydraulic fluid; and (iii) Other fluids required for normal operation of aeroplane systems, except potable water, lavatory pre-charge water, and fluids intended for injection in the engine. (b) The condition of the aeroplane at the time of determining empty weight must be one that is well defined and can be easily repeated.