Which is considered worse regarding frost on an aircraft wing?

Frost on an aircraft wing has significant aerodynamic implications, and early airflow separation is one of the most critical effects of frost. When frost accumulates on a wing, it disrupts the smooth airflow over the airfoil, which is essential for maintaining lift.

Early airflow separation means that air stops flowing smoothly over the wing surface sooner than it normally would, leading to a breakdown in the lift-generating potential of the wing. This can result in a loss of control and reduced maneuverability, particularly during critical phases of flight such as takeoff and landing. The formation of frost alters the pressure distribution around the airfoil, causing it to lose lift at lower angles of attack than it typically would.

While other options, like changing the shape of the airfoil, increasing drag, and reducing lift, are also important considerations, the immediate threat posed by early airflow separation tends to be the most severe, leading to dangerous flying conditions. When airflow separates prematurely, the aircraft can experience a stall much sooner than expected, increasing the risk during critical flight operations.