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The most common night-flight VISUAL ILLUSION is

Choices

✓ altitude over featureless terrain.correct
water, snow, dark countryside) appearing higher than it is. leading the pilot to descend prematurely. 'Featureless terrain illusion' (also called 'black hole approach'): featureless terrain or water at night provides no visual depth cues. Pilots tend to fly LOWER than intended — sometimes flying into the terrain short of the runway. Antidote: rely on instruments (altimeter, VSI, glideslope if available), use VASI/PAPI, plan steeper-than-normal approach if possible, and maintain heightened awareness during the final.
all colors appearing dimmer.
Color dimming is real (rod vs cone vision) but not the dangerous illusion.
engine noise increasing.
Engine noise is constant.
instrument lights fading.
Instrument lights have a dimmer; not an illusion.

Why

water, snow, dark countryside) appearing higher than it is. leading the pilot to descend prematurely. 'Featureless terrain illusion' (also called 'black hole approach'): featureless terrain or water at night provides no visual depth cues. Pilots tend to fly LOWER than intended — sometimes flying into the terrain short of the runway. Antidote: rely on instruments (altimeter, VSI, glideslope if available), use VASI/PAPI, plan steeper-than-normal approach if possible, and maintain heightened awareness during the final.

FAA source: PHAK Ch 17, AIM 8-1-5; AIM 8-1-5 Illusions in Flightbrowse the reference library →

Covered in Supplemental · XI — Night Operations — study the lessons free, then practice with grading and mastery tracking.

Original study question written for this course — representative of FAA knowledge-test topics, not an actual current FAA exam question.