What is used to determine the aircraft's weight and balance?

Determining an aircraft's weight and balance is a critical aspect of aviation safety and operational efficiency. The correct choice involves using load calculations that incorporate various factors like weight, fuel, cargo, and the distribution of passengers. This approach provides a comprehensive understanding of the aircraft's current weight and how that weight is distributed throughout the aircraft's center of gravity.

Weight calculations consider not only the total weight itself but also how the placement of passengers and cargo affects the aircraft's balance. This balance is vital for ensuring safe handling characteristics during flight, as an improperly balanced aircraft can lead to difficulties in control and increase the risk of accidents.

Other options do not adequately address the complexity of weight and balance determination. Flight logs provide information about previous flights, but they do not offer current weight and distribution data. Aircraft speed calculations focus on the aircraft's performance characteristics rather than its weight and balance. Weather reports, while essential for flight planning, do not contribute relevant information for determining weight and balance either. Thus, load calculations based on weight, fuel, cargo, and passenger distribution are crucial for accurately assessing an aircraft's operational readiness.