In the approach phase, how is the rate of descent primarily controlled?

During the approach phase of flight, controlling the rate of descent is primarily achieved through adjustments to the engine power. By increasing or decreasing the power output of the aircraft's engines, pilots can effectively raise or lower the aircraft's descent rate. Increasing power will result in a reduced rate of descent or a climb, while decreasing power allows the aircraft to descend more rapidly.

While other factors such as lift adjustments, speed brakes, and flaps configuration do play roles in managing overall aircraft performance, the primary method for controlling the descent rate in an approach is manipulating engine power. For instance, flaps and lift adjustments are typically used to manage the aircraft's speed and configuration, while speed brakes are employed in specific scenarios for an immediate descent but are not the primary control method during standard approaches. Thus, engine power remains the most direct and effective means for controlling descent in this phase of flight.