A below glide slope indication from a pulsating approach slope indicator is

• A. Pulsating red light
• B. Steady green light
• C. Two red lights
• D. All white lights

Answer: (A)

Visual glide-slope indicators use color and pulse to tell you where you are relative to the glide path. When you’re below the glide slope on a pulsating approach slope indicator, the signal is a pulsating red light. The red color signals you’re low, and the pulsation is designed to grab your attention so you can climb back up to re-intercept the glide path. The other patterns are not the cue for being below on this system; they indicate other statuses or positions on or off the path.