By how much can ice on an airframe increase drag?

Ice accumulation on an aircraft's airframe significantly disrupts the smooth airflow over the surfaces, which can lead to increased drag as a consequence of changes in the aerodynamic properties of the aircraft. When ice forms, it alters the airfoil shapes, effectively increasing the surface area and creating protrusions that the airflow must negotiate. This disruption can cause a marked increase in drag due to both form drag and skin friction drag.

Research and operational data indicate that ice can indeed lead to drag increases in the order of 40%. At this level, the may adversely affect the aircraft's performance by requiring more power for flight or decreasing fuel efficiency, which is critical for pilots to manage during operations in icy conditions. Understanding the impact of ice accumulation is essential for flight safety and efficiency, which is why this figure is often used in training and education within aeronautical meteorology.