What is the critical angle of attack (AOA)?

The critical angle of attack (AOA) is defined as the angle at which an airfoil reaches its maximum lift before a stall occurs. When an aircraft's angle of attack exceeds this critical threshold, airflow over the wings becomes turbulent, and the airfoil can no longer generate sufficient lift to maintain flight, resulting in a stall. This concept is crucial for pilots to understand as it directly relates to the safe operation of an aircraft; exceeding the critical angle can lead to loss of control.

In contrast, while maximizing lift and drag are significant factors in flight dynamics, they are not the defining characteristics of the critical angle of attack. Lift is indeed maximized up to a certain point, but it is the exceeding of the critical angle that leads to stalling rather than just achieving maximum lift. Similarly, drag does change with varying angles of attack, but the critical angle specifically pertains to the stall condition rather than a general drag relationship. Lastly, maintaining level flight involves numerous factors, including thrust and weight, and is not synonymous with the critical angle of attack, which specifically relates to performance limits of the airfoil during flight.