What is an Obstruction Light?

An obstruction light is a light positioned to warn aviators about a potential navigation hazard so they can exercise caution. People install obstruction lights on high terrain, tall buildings, and towers, all of which could endanger pilots, especially during conditions with poor visibility. Most nations require the use of such lights on certain types of structures, and they may be strongly recommended in other cases. They are part of a larger family of aviation lighting designed to assist pilots with navigation in a variety of conditions.

Obstruction lights may be red or white. They need to be positioned for maximum visibility, ensuring that pilots approaching from any direction can see them. An obstruction light often uses light-emitting diodes (LEDs) for lighting because they are durable and use minimal energy. To make sure pilots using night vision goggles, not normally sensitive to LEDs, can see the obstruction, other lighting or visual targets may be added for safety.

An obstruction light must have an independent power source to make sure it will continue to function even if power to the rest of the structure is lost. Most structures have several such lights for increased visibility. They may be positioned at various heights on the structure to provide information about the structure's overall shape and height. Even if pilots cannot see the structure itself, they can find the obstruction lights and know to stay away from that area.

In addition to being marked with obstruction lights, structures of a certain height need to have other visibility markers so they can be seen in the day, when lights will be hard to notice. These can include brightly painted stripes and other details designed to stand out from the surrounding environment, increasing visibility to pilots. Aviation hazards are also marked on charts so pilots know to watch out for them, but it is important to provide clear indicators for extra safety and cases where pilots go off course and are not aware of an approaching navigational hazard.

Many firms manufacture obstruction light equipment and offer consulting services to assist people with the correct placement of safety lighting. Aviation officials can also provide advice and assistance, including pamphlets outlining the law and recommended practices when it comes to properly illuminating structures that may pose a hazard to navigation. Failure to mount an obstruction light can subject people to fines and liability if a pilot becomes involved in an accident.