What effect does frost on the upper surface of an airplane wing generally have?

Frost on the upper surface of an airplane wing generally disrupts the smooth airflow over the wing. This disruption can lead to a significant increase in drag and a decrease in lift. When frost is present, the airflow becomes turbulent, which can cause the wing to stall at a lower angle of attack than it would normally stall without any frost.

When the wing is clean and properly designed, it will stall after a certain angle of attack that corresponds to its aerodynamic characteristics. However, the rough surface created by the frost interferes with these characteristics, resulting in a loss of lift at smaller angles of attack. This means that pilots must be more cautious, as the aircraft could reach stall conditions sooner than expected, making it critical to understand the impact of frost on performance.

This phenomenon is crucial for pilots to consider during pre-flight checks and in icy conditions to ensure safe operation of the aircraft. Understanding that frost lowers the angle of attack at which a stall occurs helps in preparing for changes in handling and performance during flight.