What is the purpose of Runway Centerline Lights (RCL)?

Runway Centerline Lights (RCL) are installed to provide critical lateral guidance for pilots during landing, rollout, and takeoff, especially in low visibility conditions such as fog, rain, or nighttime operations. The lights are placed along the centerline of the runway, and their primary purpose is to enhance situational awareness, helping pilots maintain the correct path and alignment with the runway. This is particularly important during approaches where visual cues may be limited and precise navigation is essential for safety.

The illumination of these lights, typically white until the last 3,000 feet of the runway where they switch to red, assists pilots in judging their position and ensuring that their aircraft remains centered on the runway throughout various phases of flight. This guidance helps prevent runway incursions and other accidents that could occur due to misalignment, particularly when visibility is compromised.

In contrast, the other options do not accurately describe the primary function of RCL. For example, while visual warnings for departing aircraft (first option) and marking thresholds (fourth option) are important elements of airport operations, they do not specifically pertain to the role of the centerline lights. Additionally, though illuminating the runway (third option) is a crucial aspect of nighttime operations, it more generally refers