Why are the distances measured from a datum in weight and balance calculations?

• A. To estimate empty weight.
• B. To calculate fuel efficiency.
• C. To determine the center of gravity.
• D. To compute maximum gross weight.

Answer: (C)

Distances are measured from a datum to determine the center of gravity because CG is found from the total moments of all weights about a fixed reference point. Each weight contributes a moment equal to weight times its arm (the distance from the datum). By summing all those moments and then dividing by the aircraft’s total weight, you obtain the center of gravity as a distance from the datum. The datum provides a consistent reference so loading configurations can be compared and the CG location can be accurately calculated regardless of how the aircraft is loaded. This process is about locating CG, not estimating empty weight, assessing fuel efficiency, or setting maximum gross weight.