What is the typical unit for CG location in weight and balance problems?

• A. Inches from the datum.
• B. Feet from the nose
• C. Centimeters from the tail
• D. Percent of wingspan

Answer: (A)

Center of gravity location is expressed as a distance from a fixed reference point called the datum. The unit used is inches from that datum because moments are calculated as weight times arm, and the arm is measured in inches along the airplane’s longitudinal axis. When you sum all the moments and divide by the total weight, the result is the CG expressed as inches from the datum. This keeps the calculations consistent and directly usable with the airplane’s weight-and-balance charts and limits. While other contexts might show CG in percent of a reference such as the mean aerodynamic chord, the typical unit in standard weight-and-balance problems is inches from the datum.