Aircraft warning lights are high-intensity lighting systems fixed to tall structures for collision avoidance purposes. Such structures include towers, broadcast masts, wind turbines, chimneys, pylons and construction equipment. Structures fitted with these lights warn aircraft of their presence to ensure they don't hit them, especially when it's dark. Two types of
aircraft warning light - white xenon discharge flashers and red lamps - are in current use. These lights tend to be arranged in groups of two or more, with one set usually placed at the top of a structure and additional sets fixed further down. Aircraft warning lights, when active, are either constantly 'on' or strobe slowly. Both types of operation ensure aircraft warning lights are visible for miles around.