Which common mistake should be avoided in weight and balance calculations?

Using outdated or incorrect weight values for cargo or passengers is a critical mistake to avoid in weight and balance calculations because accurate weight data is essential for ensuring flight safety and performance. Weight and balance directly influence an aircraft's center of gravity (CG) and overall stability. If the weight values used for the cargo or passengers are incorrect, it can lead to miscalculations, which may result in an unsafe loading condition, affecting the aircraft's handling characteristics and potentially leading to an accident.

Regular updates and checks of weight values are important because the weights of individuals can vary significantly and cargo may also change depending on its nature and how it is packed. Additionally, regulatory standards often require specific weights to be used for safety compliance, and failing to adhere to these can have legal implications for the operator.

On the other hand, using average weight values for passengers, while not ideal, is often utilized within a reasonable range to estimate weights when precise figures are not available. Including extra fuel calculations may also be necessary for certain operational considerations, and calculating weight while airborne would not typically apply, since weight and balance should always be addressed prior to takeoff. Therefore, the focus remains on the importance of ensuring accurate and current weight values to maintain safety and compliance in operations.