What effect does pro spin aileron input have on an erect spin?

Pro spin aileron input during an erect spin enhances the roll and yaw oscillations. In the context of spins, when a pilot inputs pro spin aileron (the aileron that moves in the direction of the spin), it exacerbates the asymmetry of lift and drag acting on the wings. This action increases the differential between the down-going and up-going wings, which can lead to increased rolling motion.

Additionally, in a spin, the ailerons can influence the yawing motion of the aircraft. When pro spin aileron input is applied, it adds more complexity to the spin dynamics, often resulting in more pronounced oscillations in both roll and yaw. This occurs because the pro spin aileron input creates a greater discrepancy in lift forces on the wings, causing the aircraft to roll more violently and oscillate around the spin axis.

Thus, it is this relationship between the aileron input and the resulting aerodynamic forces that leads to increased roll and yaw oscillations during an erect spin, supporting the choice that indicates more agitation in these motions.