What happens to an aircraft's climb rate when weight is increased?

When the weight of an aircraft is increased, the climb rate decreases due to the increased weight acting against the lift produced by the wings. A heavier aircraft requires more lift to ascend, and this lift is primarily generated by airspeed and angle of attack. As the weight increases, the aircraft's engines must work harder to provide the necessary thrust to achieve this lift.

In practical terms, with more weight, the aircraft's performance is affected as it needs to reach a certain speed to generate sufficient lift. Therefore, the rate at which the aircraft can climb (the climb rate) is reduced. This relationship is fundamental to understanding how weight impacts an aircraft's performance in flight, particularly during the climb phase after takeoff.

In contrast, the other options do not accurately reflect the effect of weight on climb performance. The idea that the climb rate increases proportionally with weight ignores the basic aerodynamic principles that dictate aircraft performance. Claiming that the climb rate remains unchanged disregards the direct correlation between weight and the aerodynamic forces at play. Finally, stating that the climb rate is unaffected by altitude misses the fact that altitude has a separate impact on aircraft performance due to changes in air density, which also influences the climb rate.