What happens when a heavier engine replaces a lighter one?

When a heavier engine replaces a lighter one, the empty weight of the aircraft increases. The empty weight is defined as the weight of the aircraft without passengers, cargo, or usable fuel, which includes the weight of the airframe, the powerplant, all fixed equipment, and all other necessary systems.

Replacing a lighter engine with a heavier one adds to the total weight of the aircraft, thus increasing the empty weight. This increase in empty weight can also affect the aircraft's overall performance, including its balance and center of gravity (CG) position.

The correctness of the chosen answer highlights the direct relationship between the components of the aircraft and its overall weight. The weight increase from the heavier engine affects not just the empty weight, but considerations for loading, fuel management, and performance must also be recalibrated.