Computations Using Weight and Moment Indexes
- If the weight and balance data uses moment indexes rather than arms and moments, this same alteration can be computed using a chart like the one shown on Figure 5-4.
Subtract the weight and moment indexes of all the removed equipment from the empty weight and moment index of the airplane. Add the weight and moment indexes of all equipment installed and determine the total weight and the total moment index. To determine the position of the new CG in inches aft of the datum, multiply the total moment index by 100 to get the moment, and divide this by the total weight to get the new CG.