Definition
A light source that rapidly and repeatedly varies in intensity, used in night-vision discussions as a known cause of disorientation, vertigo, or nausea in pilots, particularly when produced by a propeller, rotor blade, or anti-collision strobe passing through cockpit lighting or external light at night or in clouds.
Plain English
A light that keeps flashing or pulsing on and off quickly. At night or in cloud, this kind of flashing inside or near the cockpit can make a pilot feel dizzy, disoriented, or sick.
Context Anchor
Encountered during night flying, especially with cockpit lighting, warning lights, rotating beacons, strobes, or other lights seen through the windshield.
Derivation
Flicker comes from an old word idea of quick, fluttering movement. That helps here because the light seems to flutter on and off, or brighter and dimmer, instead of staying steady.
Why Pilots Care
Mistaking a steady light for a flickering one can lead to misidentification of other aircraft, runway lights, or beacons and reduce situational awareness at night.
Grounding Statement
Picture a dim cockpit at night with one small light blinking over and over; even if it is not bright, your eyes keep getting pulled to it.
Intuition Check
Do not treat a flickering light as just a minor irritation. In night flying, repeated flashing or pulsing light can affect attention, comfort, and orientation.
Example Sentence 1
The pilot switched off the anti-collision strobes after entering cloud because the flickering light reflecting off the mist was causing disorientation.
Example Sentence 2
When the student reported a flickering light on final approach, the instructor explained it was the runway end identifier lights seen through night-adapted eyes.