Answer :
Final answer:
Approach lighting systems (ALS) (d) are installed on some precision approach runways to assist landings under adverse visibility conditions, giving vital visual cues to pilots.
Explanation:
The equipment installed on some precision approach runways to facilitate landing under adverse visibility conditions are Approach lighting systems (ALS). These specialized lighting fixtures enhance the visibility of the landing environment and guide pilots towards the runway. They are particularly vital during low visibility conditions such as fog, rain, or heavy cloud cover.
ALS typically consists of a series of light bars, strobe lights, or a combination thereof that extend outwards from the runway threshold. In contrast, runway edge lights outline the edges of the runway, runway centerline lights illuminate the center of the runway, and runway threshold lights denote the beginning of the runway. However, it's the approach lighting systems that are crucial for providing the visual cues necessary for a precision approach.
