Project Blue Book Final Case Report

The disorientation that pilots experience during night formation flight may result
from what is called the autokinetic illusion. The autokinetic illusion is a visual
phenomenon in which a stationary spot of light against a dark background appears to
move erratically. It is known to have been experienced by pilots when they were
observing formation lights on other aircraft (8). In fact, this illusion can discomfort a
trained pilot to the extent that he will spin in a link trainer (8). In a recent night formation
flight accident a surviving pilot reported that he “saw” the other two aircraft in the
formation peel-off to the left when actually, they had not changed course (16). On the
basis of this false information he maneuvered his aircraft so as to collide with the other
two with the resultant loss of one pilot and three F-86D aircraft. The “peeling-off” of
those two aircraft is typical of the nature of the autokinetic illusion.
Investigations of the autokinetic illusion reveal that the apparent movement is
greatest and most frequent when small (point-source), dim lights are being viewed but it
is still present in the case of large light sources (6, 7) and, although to a lesser degree,
when viewing patterns of lights (8). Therefore, the use of more or larger area reference
lights in formation flight should cause a reduction in the autokinetic effect. It has been
demonstrated that autokinetic movement was frequent and large when only one reference
light was visible during formation flight, was much reduced when two reference lights
were visible, and reduced even more when tree [three?] reference lights were visible (8).
REFERENCE WADC TR 55-124