What do LIRLs provide at an airport?

Low Intensity Runway Lights (LIRLs) are specifically designed to provide visibility and guidance to pilots during landings and takeoffs, particularly in lower light conditions. These lights illuminate the runway edges and are especially useful at night or during periods of low visibility, giving pilots a clear visual indication of the runway boundaries.

LIRLs are less intense than their high and medium-intensity counterparts, allowing for effective runway illumination without causing glare that could impair a pilot’s vision. This feature is particularly advantageous at airports that may not experience high traffic levels or where operations primarily occur under visual flight rules (VFR) but still require a reliable lighting system for safety.

In contrast, high and medium-intensity lighting systems serve different purposes and are typically utilized at larger airports or for runways with heavier traffic, where greater visibility is needed. Visual Flight Rules Indicators would pertain to instruments or systems indicating weather conditions favorable for VFR flight but do not specifically relate to runway lighting. Therefore, the choice of Low Intensity Runway Lights as the answer is accurate, as they fulfill the role of providing vital runway edge guidance under specific circumstances.