When too much weight is added to an aircraft, what happens to its rate of climb?

When excess weight is added to an aircraft, its ability to climb is adversely affected due to the principles of aerodynamics and physics. More weight requires a greater amount of lift to achieve the necessary altitude gain. The aircraft's engines must work harder to overcome this additional weight; this increased demand often exceeds the available power and performance capabilities of the aircraft.

As the weight increases, the aircraft's thrust-to-weight ratio diminishes, meaning that there is less thrust available relative to the weight of the aircraft. This results in a decrease in the rate of climb since the aircraft cannot generate enough lift to overcome gravity efficiently. Consequently, an overloaded aircraft will have a lower climb rate, which can impact safety and operational effectiveness.