How do you perform a weight-and-balance calculation to verify that the aircraft CG lies within limits?

• A. Subtract the front arm and aft arm weights to compute CG
• B. Sum weights and moments (weight × arm) for all items; compute total weight and total moment; CG = total moment/total weight; compare with CG limits
• C. Add all weights and divide by 2
• D. Use only fuel weight to determine CG

Answer: (B)

Weight-and-balance verification uses the center of gravity as the weighted average of all loads about a reference datum. For every item on board, multiply its weight by its arm (the distance from the datum) to get its moment. Sum all those moments to obtain the total moment, and sum all the weights to get the total weight. The CG is then found by dividing the total moment by the total weight. Finally, compare this CG to the aircraft’s approved forward and aft limits to confirm it lies within range. If it’s outside, adjust the payload, baggage, or fuel to bring it back inside the limits.

This approach is necessary because every load contributes to both total weight and the distribution of that weight along the fuselage. Merely subtracting certain arms, averaging weights, or using only one item (like fuel) doesn’t account for how far each load sits from the datum, so it can’t reliably indicate true balance.