What determines if additional fuel can be taken on board?

The decision regarding whether additional fuel can be taken on board primarily relies on weight and balance calculations. Each aircraft has a maximum weight limit that includes its operating weight, payload, and fuel. If additional fuel is added, it increases the overall weight, which must be kept within the aircraft's approved maximum gross weight for safe operation.

Weight and balance calculations take into account the distribution of that weight and how it will affect the aircraft's center of gravity. An aircraft that is improperly loaded can experience handling difficulties, increased drag, and even structural issues during flight. Therefore, before any fuel is added, pilots must ensure that the weight remains within acceptable limits and that the center of gravity stays within allowable parameters to ensure safety and performance.

While flight duration, aircraft type regulations, and altitude requirements can influence fuel planning decisions, they do not determine the physical capability of carrying additional fuel in the context of weight and balance. This is why weight and balance calculations are the fundamental factor in determining whether more fuel can be taken on board.