What causes adverse yaw during a coordinated turn?

• A. The aileron that is down produces more induced drag, yawing the airplane opposite the turn.
• B. An upgoing wing's drag causes yaw in the direction of the turn.
• C. Rudder input alone causes adverse yaw.
• D. Tailplane drag is the primary cause of adverse yaw.

Answer: (A)

Adverse yaw comes from how lift and drag change unevenly when you roll with the ailerons. The wing that moves downward is deflected by its aileron, increasing its angle of attack and camber, which boosts lift but also increases induced drag on that wing. The extra drag on the downgoing wing yaws the airplane’s nose toward the outside of the turn (opposite the direction you’re rolling). To fly a coordinated turn, you counter this yaw with rudder so the nose stays aligned with the flight path. The upgoing wing doesn’t create as much induced drag, so it isn’t the source of the adverse yaw. Rudder input isn’t the cause either; it’s the means to counteract the effect. Tailplane drag exists but isn’t the primary reason for adverse yaw.