Abstract: A rotary encoder of a control surface has a display. The display includes a ring of light emitting elements, such as light emitting diodes (LEDs), in the control surface around the shaft and knob of the rotary encoder. The rotary encoder has a shaft that rotates about an axis under control of an operator. The rotary encode has an output providing a signal indicative of the rotational movement of the shaft. A knob engages the shaft and is used by the operator to rotate the shaft. The knob, in general, has a narrow stem that engages the shaft of the rotary encoder and extends away from the control surface, and a top portion which the operator manipulates to turn the knob. The stem has a substantially circular cross-section, in a plane perpendicular to the axis of the shaft of the rotary encoder, with a narrow diameter.