Definition
A visual illusion, also known as the 'black hole approach,' in which an approach to a runway over an area without surface features — such as water, dark terrain, or featureless ground — creates the impression that the airplane is higher than it actually is, leading the pilot to fly a lower-than-normal approach.
Plain English
When you fly toward a runway over dark or empty ground at night, your eyes have nothing to judge height against, so the runway looks farther below you than it really is. You end up flying lower than you should — sometimes dangerously low.
Context Anchor
Encountered during night landings or descents over dark, flat, snow-covered, or unlighted areas where the runway or landing area has few outside visual references.
Derivation
Featureless' means lacking distinguishing marks or features. The term describes terrain — the ground between the pilot and the runway — that offers no visual cues like lights, roads, buildings, or texture for the eye to use as a height reference.
Why Pilots Care
Unrecognized, it produces an excessively low approach that can result in collision with terrain or obstacles short of the runway.
Grounding Statement
If the ground below looks like a dark blank area, your eyes may not give you a reliable sense of how high you are.
Intuition Check
Do not assume “featureless terrain” just means boring or empty-looking ground. In this FAA context, it means the ground lacks enough visible detail for your eyes to judge height and distance reliably.
Example Sentence 1
On the night approach over the lake, the instructor reminded the student to watch for the featureless terrain illusion and verify the glidepath on the VASI.
Example Sentence 2
The instructor reminded the student to watch for the featureless terrain illusion when landing at the coastal airport after dark.