How is Vref calculated?

Vref, or reference speed, is a critical airspeed used during the landing phase of flight. It is primarily determined to ensure that the aircraft maintains a safe margin above stall speed (VS) while being configured for landing. The calculation of Vref typically involves using a multiplier of stall speed in landing configuration.

The correct calculation involves using 1.3 times the stall speed (VS) in landing configuration. This figure provides a balance that ensures sufficient lift and control during the landing approach while accounting for various flight conditions and aircraft configurations. Cubic changes in weight and configuration adjustments accentuate the need for this safety buffer, and a multiplier of 1.3 allows for accounting for these elements appropriately.

In this case, 1.3 VS ensures that pilots have a reference speed that promotes effective control in the landing phase without the risk of entering a stall condition. This is important for pilot awareness and safety, making it essential to establish a reliable Vref that accounts for the aircraft's behavior under landing conditions.