What effect does frost have on the performance of an aircraft before takeoff?

Frost affects the performance of an aircraft before takeoff primarily by increasing stall speed. When frost accumulates on the wings and control surfaces, it disrupts the smooth airflow over these surfaces. This disruption results in an increase in drag and a decrease in lift, requiring the aircraft to reach a higher speed to achieve the necessary lift for takeoff.

As stall speed is defined as the minimum speed at which an aircraft can maintain level flight, an increase in stall speed means the aircraft will need to be flown at a higher speed to avoid the risk of stalling. The presence of frost effectively alters the aerodynamic properties of the aircraft, making it less efficient. Therefore, operators must be aware of frost on the wings as it can significantly impact safety during takeoff.