The Approach Lighting System (ALS) is designed to provide pilots with what information during approach?

• A. It provides runway edge lighting only for visual reference.
• B. It provides lights that will penetrate the atmosphere far enough from touchdown to give directional, distance, and glidepath information for safe transition from instrument to visual flight.
• C. It supplies weather information on a cockpit display.
• D. It calibrates instrument indications during instrument flight.

Answer: (B)

The main idea is that the Approach Lighting System gives you a visible cueing path that helps you locate the runway environment and stay on the intended approach path as you move from instrument-based flying to visually established flight. By lights that extend outward toward you, it helps you determine alignment with the runway centerline (direction), how close you are to the runway (distance), and, visually, your descent path toward the threshold (glidepath). This setup is crucial for a safe transition in low visibility or at night, because it lets you gauge your position and angle without relying solely on instruments. It does not provide weather data, nor does it calibrate instrument indications, and it isn’t limited to runway edge lighting; its purpose is to give comprehensive visual cues to guide the approach and landing.