When are Runway Threshold Identification Lights (RTILs) required?

Runway Threshold Identification Lights (RTILs) are specifically designed to enhance the visibility of the runway threshold, particularly when it is challenging for pilots to visually identify the runway in poor weather conditions or other circumstances that impair visibility. The requirement for RTILs becomes essential in situations where the terrain around an airport does not permit the installation of approach lights. Approach lights are instrumental in guiding aircraft during the final approach to a runway, especially in low visibility. However, when the environment around the airport—such as mountainous areas, obstacles, or geographical limitations—prevents the installation of these lights, RTILs serve as a critical aid for pilots to safely determine the location of the runway threshold. This makes the presence of RTILs essential in these specific circumstances to improve safety and navigational efficiency during landing.