What is the purpose of a weight and balance calculation in commercial flight?

The purpose of a weight and balance calculation in commercial flight is fundamentally to ensure the aircraft is loaded within its specified weight limits. This is critical for safe operations because every aircraft has defined maximum weight limits that include the maximum takeoff weight, maximum landing weight, and other relevant thresholds. Exceeding these limits can significantly affect the aircraft's performance characteristics, including climb rate, stall speed, and control response, which can pose serious safety risks during flight.

Properly conducting a weight and balance calculation also ensures that the center of gravity (CG) is within acceptable limits. An aircraft that is improperly loaded can become difficult to maneuver or, in the worst cases, uncontrollable. By verifying that the loading is compliant with regulations and manufacturer guidelines, pilots can ensure a safe and efficient flight, optimizing both performance and safety.

The other options focus on different aspects of flight planning or performance and do not relate directly to the primary function of weight and balance calculations. For instance, while calculating fuel needs is essential for trip planning, it does not directly influence whether the aircraft is loaded within safe parameters. Similarly, determining flight paths and assessing engine performance are important but are secondary to the initial task of ensuring that the aircraft is within weight limits and properly balanced before takeoff.