An aircraft wing comprising: a leading element; a trailing element positioned behind the leading element relative to a direction of movement of the aircraft; an actuation system for moving one of the elements between a retracted position and an extended position in which there is an air gap between a lower surface of the leading element and a surface of the trailing element. The arrangement comprises a public telephone. The processor operates to implement a first power management functionality and generate first power management data. The sensing circuit senses incident light and provides an output indicative of the incident light. A ground plane layer is formed on the insulator layer.