What does the term “stall speed” refer to in an aircraft?

Stall speed refers to the minimum speed at which an aircraft can maintain controlled flight in a given configuration, such as during landing. When the aircraft is flown below this speed, it risks stalling, losing lift and control due to airflow separation over the wings. In landing configuration, which often includes full flaps and landing gear extended, the stall speed typically decreases, making it essential for pilots to maintain an appropriate airspeed to ensure safe landings.

While the stall speed varies depending on the aircraft's weight, configuration, and environmental conditions, it is crucial for pilots to understand this concept to prevent a stall during critical phases of flight like landing. This understanding directly impacts flight safety and performance, making knowledge of stall speed indispensable for effective aircraft operation. The other options refer to different speed parameters that do not align with the definition of stall speed.