PLT333: Night Vision
What code PLT333 covers, why the FAA tests it, and how to study Night Vision before your checkride.
Recall physiological factors - night vision
What this means for your checkride
Night vision depends on the rods at the edge of the retina, which are far more light-sensitive than the cones but see no color and are absent at the center of vision. They take roughly 30 minutes to fully adapt to darkness, and bright light resets that adaptation.
Night flying safety rests on protecting and using night vision correctly, so the FAA tests dark adaptation, off-center viewing, and the effects of altitude and bright light.
Pilots look straight at a dim object at night to see it better. Because the center of vision has no rods, a faint light disappears when stared at directly; you see it better by looking slightly to the side, using off-center viewing.
Where to study it
Practice questions on this code
Real questions from the Aviator IQ bank that test this exact area. Answer each to see the correct choice, the full rationale, and the FAA source.
At night a dim object viewed directly at the center of the visual field tends to fade because of the night blind spot. To see the object clearly, how far off center should the pilot look?
Once the eyes are fully dark-adapted, the rods become the primary receptors for night vision. Approximately how much more sensitive to light are the rods than the cones?
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.
How should you look for traffic or a dim light at night?
Off center, about 5 to 10 degrees to the side, because the center of vision has a night blind spot with no rods. Staring directly at a faint object makes it fade, so I scan with slight off-center glances.
How do you protect your night vision before and during a flight?
Allow about 30 minutes for the rods to dark-adapt, avoid bright white light, and use red or dim cockpit lighting, remembering that bright light resets the adaptation. Rods are far more light-sensitive than cones but see no color.
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.