ATPL Human Factors Practice Test

Flicker vertigo is primarily caused by exposure to certain visual stimuli that involve rapidly flashing lights or patterns, particularly at specific frequencies that can disrupt the brain's processing of visual information. In aviation, this is notably a concern with strobe lights and the rotating blades of an aircraft, especially when they create flickering patterns against a moving background, such as the ground or the sky.

The combination of low RPM and strobe lights plays a significant role in the development of flicker vertigo. Low RPM refers to the reduced rotational speed of an aircraft's blades, leading to a situation where the blades can appear to be more prominent in the pilot's field of vision as they pass through the light source, causing a stroboscopic effect that can induce dizziness or disorientation. Thus, the specific interaction of strobe lights and aircraft blades under low RPM conditions creates the most pronounced effect that can lead to flicker vertigo.

Other options mention bright lights and rapidly moving objects, but those don't encompass the specific mechanisms witnessed in aviation scenarios that induce flicker vertigo. The presence of bright light might contribute to discomfort or glare, but it’s the combination of low RPM with strobe lights that creates the significant risk associated with flicker vertigo in flight