Center of Gravity

The center of gravity (CG) tells you where the aircraft’s total weight can be considered to act as if it were concentrated at a single point. It is found by dividing the total moment by the total weight because moment is the turning effect produced by each weight about a reference datum, so the weighted average of all the arms gives the balance point. If the CG moves too far forward or aft, the aircraft’s handling and stability can change significantly.

Use this formula in weight-and-balance calculations for airplanes, helicopters, and loaded cargo when you need to find the overall balance point. It is especially important before takeoff, after loading passengers or baggage, or when checking whether an aircraft stays within its approved CG limits.

• Using the wrong reference datum or arm units
• Dividing by the number of items instead of the total weight
• Mixing units, such as moments in lb-ft and weight in pounds without converting consistently