PLT147: Visual Glidepath Indicators
What code PLT147 covers, why the FAA tests it, and how to study Visual Glidepath Indicators before your checkride.
Recall airport operations - visual glide path indicators
What this means for your checkride
Visual glidepath indicators such as the VASI and the precision approach path indicator (PAPI) use colored lights beside the runway to show whether you are on, above, or below the correct approach path. On a two-bar VASI, red over red is too low, white over white is too high, and red over white is on the glidepath.
These lights give a stabilized approach without instruments, so the FAA tests whether you can read the color combinations and correct your descent from them.
Candidates mix up the colors. The memory aid is red over white, you are all right; two reds mean you are too low and need to climb, which is the dangerous side near terrain.
Where to study it
Oral checkride defense
A code on your report is an area the examiner can revisit. Here is how an examiner might probe it, and how to explain it out loud.
You see two red and two white on the PAPI. Where are you?
On the correct glidepath. Explain the progression: more red means low, more white means high, all red is well below path, all white is well above. For a two-bar VASI, red over white is on path and two reds mean too low.
Why fly the VASI or PAPI even in day VMC?
It gives a stabilized, obstruction-clear descent to the touchdown zone, keeps you above terrain and obstacles on final, and supports a consistent aim point and landing.
A code on your test report is an area of deficiency. An authorized instructor must review it with you and endorse that review before you take the practical test, and the examiner may revisit it during the oral. Study it until you can explain it out loud, not just recognize the answer.