What effect does ice accumulation have on drag during flight?

Ice accumulation on an aircraft's wings and control surfaces significantly alters the aerodynamics of the aircraft by changing its shape and smooth airflow characteristics. When ice forms on these surfaces, it disrupts the airflow, causing increased turbulence and a reduction in lift. This turbulent airflow creates additional friction that leads to a notable increase in drag.

The added weight of the ice, combined with the degradation of the aerodynamic properties of the wings, means that the aircraft not only experiences more drag but also may require a greater amount of thrust to maintain its speed and altitude. Hence, the correct understanding of the impact of ice accumulation on drag is that it increases drag, which can negatively influence performance and controllability during flight.