Low Intensity Lights (LIRL) are used primarily for what situation?

Low Intensity Runway Lights (LIRL) are designed primarily for use at airports which facilitate visual approaches. They provide adequate illumination for pilots during approach and landing, particularly in conditions where the visibility may not be optimal but still allows for visual flight rules (VFR).

The application of LIRL is most beneficial in circumstances where fine detail in ground navigation is needed under clear or marginal visibility, making them appropriate for runways specifically used for visual approaches where pilots rely on visual references rather than instrumented guidance. These lights are less intense than other runway lighting systems and are advantageous because they reduce glare and facilitate a clearer view of the runway environment, crucial for safe landings by visual means.

In contrast, runways associated with non-precision and precision instrument approaches typically require more intense lighting systems to support the use of instrument flight rules (IFR), where aircraft rely heavily on instruments for guidance. Control towers do not fundamentally affect the type of lighting most beneficial for various approach categories but are primarily operational facilities. Therefore, the use of LIRL is most aligned with runways catering to visual approaches.