Private Pilot Private Exam

What causes an airplane (excluding a T-tail design) to pitch nose-down when power is reduced?

1. The reduction of downwash on the elevators from the propeller slipstream

2. The loss of lift due to decreased airspeed

3. Increased aerodynamic drag on the tail

4. The shift of weight forward in the aircraft

The correct answer is: The reduction of downwash on the elevators from the propeller slipstream

The correct answer identifies that when the power is reduced, there is a reduction in the downwash created by the propeller slipstream, which directly affects the control surfaces, particularly the elevators. In conventional tail designs—where the elevator is located at the tail—the reduction of power means the amount of airflow that is directed downward over the tail decreases. This results in less lift generated by the elevators, and consequently, the nose of the aircraft pitches down. The dynamics of airflow are crucial to understanding this phenomenon because the propeller creates a slipstream that enhances the effectiveness of the elevators by increasing the downwash hitting them. When power is reduced, this effect diminishes, leading to a reduction in the lift generated by the horizontal tail. Although other factors are at play in flight dynamics, the primary reason for the nose-down pitch in this scenario is directly tied to the impact of the reduction in downwash on the elevators, making this the best explanation among the provided options.