What does the "white arc" on the airspeed indicator signify?

The "white arc" on the airspeed indicator signifies the flap operating range. This range indicates the speeds at which it is safe to extend or retract the flaps, as well as the maximum allowable speed for flap extension. Typically, this area highlights the slower speeds associated with safe flap operations, ensuring that pilots can manage the aircraft effectively during critical phases of flight, such as takeoff and landing. Knowing the flap operating range is essential for maintaining control and ensuring safe maneuvering, especially during approaches or low-speed operations.