Between January 1979 and May 1993, 35 aircraft accidents
occurred in Australia during the take-off phase of flight at night.
A primary factor in 15 of these accidents was considered to be some
form of visual or sensory illusion, or spatial disorientation.
Investigation files from the 15 accidents were reviewed in an
attempt to identify common elements in which spatial
disorientation, or a visual or sensory
illusion, was thought to be a contributing factor. Data were
gathered on pilot characteristics, such as experience and age, as
well as on operational information, such as aerodrome type and
weather. Relevant regulations pertaining to the operation of
aircraft at night and training for night operations were
The report concludes that the type of pilot training or pilot
qualification did not appear to be a common factor in the accidents
under consideration. Pilot
experience also did not appear to be a factor in the accidents.
The absence of adverse weather may be significant in the onset of
illusions. Furthermore, it was considered that the absence of both
ground lighting and a horizon was paramount in the development of
the accidents, while the combination of a
limited horizon with no adverse weather was the most probable
condition under which illusions were likely to develop.