An illusion caused on dark nights when one stares at a single light source for a long time, and it appears to move when in fact it is stationary. This can create confusion and make it difficult to distinguish between real and apparent movement. During night formation flying, if any member of the formation looks at a single light of the lead aircraft, he or she may experience this illusion. The chances of experiencing this illusion are reduced by increasing the number of lights, having lights with better intensity, and increasing the size of the lights. The illusion can be overcome by simultaneously looking at more than one light or by having blinking lights.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved