Flashing Light (Fl)

A rhythmic navigation light whose periods of light are shorter in total than its periods of darkness.

The flashes may occur singly or in a repeating group, and the charted characteristic states the pattern, colour and period. For example, a group-flashing light repeats a specified number of flashes before a longer interval of darkness. A flashing characteristic is distinguished from an occulting light, in which light is shown for longer than darkness. Identification should be based on the complete charted characteristic rather than on a brief glimpse, especially where several aids to navigation are visible together.