Section 23.2100 - Weight and center of gravity(a) The applicant must determine limits for weights and centers of gravity that provide for the safe operation of the airplane.(b) The applicant must comply with each requirement of this subpart at critical combinations of weight and center of gravity within the airplane's range of loading conditions using tolerances acceptable to the Administrator.(c) The condition of the airplane at the time of determining its empty weight and center of gravity must be well defined and easily repeatable.