What is a stall in the context of aviation?

A stall in aviation refers specifically to a condition in which the airflow over the wings begins to separate from the wing surface, leading to a significant and sudden loss of lift. This phenomenon occurs when the angle of attack, which is the angle between the chord line of the wing and the oncoming airflow, exceeds a critical threshold. When this critical angle is surpassed, the smooth airflow transitions to turbulent airflow over the wings, drastically affecting lift generation.

Understanding stalls is essential for pilots because they typically occur at lower airspeeds and higher angles of attack, particularly during maneuvers such as turns, climbs, or when an aircraft is in a landing configuration. Recognizing the signs of an impending stall and knowing how to recover from one is crucial for safe flying. The other choices do not accurately capture the essence of a stall: they describe different flight scenarios or maneuvers unrelated to the aerodynamic principle of airflow separation over the wings.