Which sequence correctly describes how to compute CG and total weight from a weight-and-balance sheet?

• A. Tally all load weights, locate their arm positions, compute each moment, sum moments, sum weights, CG = total moments/total weight, verify within limits.
• B. Tally the main weight only and divide by the number of load items.
• C. Compute CG first, then estimate weight distribution.
• D. Randomly assign weights and moments until CG looks reasonable.

Answer: (A)

Calculating CG and total weight from a weight-and-balance sheet relies on treating each item as a weight located at a specific arm. The center of gravity is the balance point of the aircraft, found with CG = (sum of weight_i × arm_i) / (sum of weight_i). To do this, you first tally every item's weight and its arm, compute each item’s moment (weight × arm), sum all the moments, and sum all the weights. Then divide the total moments by the total weight to obtain the CG. After that, compare both the total weight and the CG to the aircraft’s permitted limits for the current configuration.

This approach matters because different items sit at different distances from the datum, so their moments contribute differently to balance. You can’t just weigh the main item or average by the number of items, since that ignores how far each item is from the reference point. Nor can you compute CG before knowing all weights, since the result depends on every contribution. Randomly guessing weights and moments won’t yield a valid balance.