Multiple choice

A red on red indication on a standard VASI defines which condition?

  1. Above glide slope

  2. Below glide slope

  3. Instrument malfunction

  4. Depends from airport to airport

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Red-on-red means you're below the glide slope and need to climb to get back on the proper descent path. VASI lights use color to signal your position: white-on-white (too high), red-on-white (on glide slope), and red-on-red (too low). You're dangerously low if you see all red lights.