What color are the threshold lights?

Threshold lights are designed to indicate the beginning of the runway and provide pilots with essential visual cues during landing and runway approaches. Specifically, threshold lights are green in color, which helps in identifying the runway's start. This green coloration is universally recognized and serves to improve safety by clearly marking the runway's usable area.

The other color options, such as red, blue, and yellow, have distinct meanings in aviation but do not represent the color of threshold lights. For instance, red lights are typically used to indicate the stop or end of a runway area, while blue lights are often used for taxiway edge lighting, and yellow lights are frequently seen in various other aviation applications, including runway and taxi markings. Understanding the specific roles and meanings of these colors is important for the effective navigation and operation within an airport environment.