What is the "white arc" on the airspeed indicator?

The "white arc" on the airspeed indicator represents the flap extension speed range. This range indicates the speeds at which flaps can be safely extended without risking damage to the aircraft or compromising performance. When the flap indicator falls within the white arc, it signals that the aircraft is operating within the limits for deploying flaps, which is crucial for safe landing and approach maneuvers.

The white arc is important for pilots to understand, as extending flaps at or above the maximum flap extension speed could lead to control issues or structural failure. This is why the awareness of flaps and their corresponding speeds is emphasized during training, as they play a significant role in enhancing lift and controlling the aircraft during lower speed operations, particularly during landing configurations.