What is the stall speed in landing configuration (VSO)?

The stall speed in landing configuration, commonly referred to as VSO, is defined as the minimum steady flight speed at which the aircraft is controllable in a landing configuration, typically at a specified weight and center of gravity. This speed is crucial for pilots to know because it indicates the threshold at which the aircraft can begin to stall while it is configured for landing, such as with flaps extended.

The correct choice references an actual value you might find on the aircraft's performance charts, which vary depending on the aircraft type and its specific configuration for landing. For instance, if the listed stall speed in the approach configuration of a specific aircraft is 85 knots, then that is the value that should be used as the reference speed when preparing to land.

Other choices might represent stall speeds under different configurations, such as clean stall speed (without flaps), or might be incorrect figures entirely. Understanding stall speeds in various configurations is vital for pilots to avoid stall situations during critical phases of flight like landing.