Aircraft warning lights (AWL) are required to have specific features in terms of beam pattern, light intensity, light color, and number of lights based on international regulations and national standards. The setup of structure’s AWL system will vary depending on local terrain features, weather patterns, geographical locations, and the shape & layout of the structure or surrounding structures that need to be lit. 

1.Types of Lights

According to the ICAO, the lights used in an AWL system must be distinguished by a set of parameters: beam patter, color, intensity, and flash rate. There are 3 main groups to consider as stated by the ICAO:

• Low intensity obstruction lights: these lights should be used where the object height above the surrounding ground is lower than 45 m.

• Medium intensity obstruction lights: should be used where the object height above the level of the surrounding ground is higher than 45m.

• High intensity obstruction lights: these lights should be used to indicate the presence of an object if its height above the level of the surrounding ground exceeds 150m.

2.Location of Lights

The number of light units will depend on the diameter & shape of the structure. The lights should be arranged in a manner that allows the object to be seen from every angle in azimuth, giving clear indication of the size, shape, and diameter of the structure. The FAA has set up dimensional guidelines that state that any object with a diameter of up to 6m will require 3 lights, and any object with a diameter of greater than 6m will require 4 lights.