When should a pilot conduct a weight and balance calculation?

A pilot should conduct a weight and balance calculation prior to every flight to ensure safety and compliance because it is critical for maintaining the aircraft's performance and handling characteristics. Proper weight and balance calculations help ensure that the aircraft operates within its specified limits, which is essential not just for safety, but also for regulatory compliance.

Weight and balance affect various flight parameters, including takeoff distance, climb performance, fuel efficiency, and overall stability. Variations in weight due to passenger, cargo, or fuel loads can significantly alter how an aircraft performs. By checking weight and balance before each flight, pilots can adjust loads appropriately and avoid situations that may lead to hazardous conditions, such as being overweight or improperly balanced.

Other options suggest limiting these calculations to specific events or frequencies, which does not adequately address the variability that can occur with each flight. Thus, conducting these calculations before every flight is the best practice for safe aviation operations.