What is the lower limit of the white arc also known as?

The lower limit of the white arc is referred to as Vso, which stands for "stalling speed in the landing configuration." This speed is critical for pilots, as it indicates the minimum airspeed at which the aircraft can maintain controlled flight in the landing configuration, typically with full flaps extended.

Understanding Vso is essential for safe landing practices, as flying below this speed can lead to a stall, particularly during approaches and landings when pilots are often operating at lower speeds. The white arc on the airspeed indicator encompasses the range of airspeeds for safe flight with flaps extended, indicating the operational limits for this configuration.

In contrast, the other terms refer to different airspeed limits: Vfe signifies the maximum flap extended speed, Vno indicates the maximum structural cruising speed, and Vne represents the never exceed speed. Knowing these distinctions helps pilots manage their operational limits correctly for various phases of flight.