When does the stall occur during flight?

The stall occurs when the critical angle of attack is exceeded, which is the defining condition that leads to a loss of lift. Every airfoil, including the wings of an aircraft, has a specific angle of attack at which it can generate the maximum amount of lift. Beyond this critical angle, airflow begins to separate from the upper surface of the wing, resulting in a significant decrease in lift and the onset of a stall, regardless of the airspeed.

In practice, a stall is not solely a function of airspeed; it can happen at any speed if the angle of attack is too steep. Understanding the relationship between angle of attack and stall is crucial for pilots, as it helps them maintain safe flight operations and prevent unintentional stalls.

The other scenarios do provide contexts where stalls might occur or be encountered, but they do not account for the fundamental reason why a stall happens. For instance, while stalls can happen at low airspeeds and during climbs, these conditions are not the direct cause of a stall. Instead, it is the exceedance of the critical angle of attack that is the primary factor leading to a stall condition.