Which statement about stall is correct?

A stall occurs when an aircraft exceeds its critical angle of attack, leading to a significant loss of lift. The critical angle of attack is the angle at which the airflow begins to separate from the wing's upper surface, resulting in a decrease in lift generated by the wing. When an aircraft operates beyond this angle, it cannot maintain laminar airflow, which is essential for efficient lift production.

This phenomenon is not exclusive to low-speed scenarios; stalls can happen at various speeds, particularly when maneuvers cause the angle of attack to increase rapidly. The idea that stalls could be corrected simply by reducing altitude is misleading, as it does not address the fundamental aerodynamic issue—the angle of attack must be decreased to recover from a stall. Reducing thrust is not a primary cause of a stall; rather, it is the angle of attack that determines whether lift can be effectively generated.

In summary, recognizing that a stall occurs at the critical angle of attack is crucial for pilots to understand the aerodynamic principles operating in flight, aiding in prevention and recovery techniques.