A visual signal displayed on an airfield to give local air traffic rules information to flight crews in the air. These signals are displayed in a signal area 12 m2
and bounded by a white border. Such signal areas are located at aerodromes where general aviation movements are significant. The signal area, or signal square
as it is more commonly known, is located so that it is easily visible from all directions of approach. The signals in the illustration can be seen in the signal area.