Which Statement About Runway Edge Lights Is Correct?

• A. They Are Turned On Only At Night
• B. They Are Not Used For IFR Operations
• C. They Are Turned Off At Sunrise
• D. They Are Turned On Between Sunrise And Sunset When Surface Visibility Is Below 2 Miles

Answer: (D)

Runway edge lights exist to define the runway boundaries and aid depth perception, especially when visibility is limited or it's dark. They’re not restricted to nighttime use; in daylight, if surface visibility drops to a low level, turning the edge lights on helps pilots see the edges more clearly and maintain proper alignment. The idea that lights are turned on during daylight hours when visibility is below a certain threshold—here, below 2 miles—reflects their role in enhancing runway identification in marginal conditions. The other statements miss how these lights are used: they aren’t only for night, they do support operations under instrument conditions, and they aren’t automatically off at sunrise.