What happens when airflow separates from the upper surface of a wing?

When airflow separates from the upper surface of a wing, it can lead to stall conditions. This phenomenon occurs when the smooth airflow over the wing is disrupted, which typically happens at higher angles of attack. As the wing exceeds its critical angle of attack, the airflow can no longer adhere to the upper surface, resulting in a loss of lift.

When the lift diminishes significantly due to this separation, the aircraft may experience a stall, characterized by a sharp drop in lift and an increase in drag. This condition can cause the aircraft to lose altitude and control effectiveness, making it crucial for pilots and mechanics to understand the dynamics of airflow and aerodynamics to safely manage flight conditions. Recognizing the signs of impending stall and understanding how to recover from it is essential for maintaining aircraft performance and safety during flight.