Natural sunlight and its association to civil aviation accidents.
BACKGROUND
Glare is a temporary visual sensation produced by luminance within the visual field that is significantly greater than that to which the eyes are adapted. Glare from natural and artificial light sources can result in temporary visual impairment, increasing the risk of an accident. This study investigates the relationship between visual impairment from natural sunlight and aviation accidents.


METHODS
The National Transportation Safety Board Aviation Accident/Incident Database was queried for the period January 1, 1988 to December 31, 1998 for terms, which included "sun," "glare," "vision," "blind ed," and "reflections." Reports annotated with one or more of these terms were reviewed to determine whether glare was considered a direct or contributing factor in the event.


RESULTS
There were 130 accidents in which glare was found to be a contributing factor. The majority of these events occurred during clear weather and atmospheric conditions (85%), and were associated with approach/landing and takeoff/departure phases of flight (55%).


CONCLUSIONS
Exposure to glare from natural sunlight has contributed to aviation accidents, primarily under otherwise optimal visual conditions at low altitude in congested airspace. Preventative techniques are presented that may protect a pilot's visual performance against the debilitating effects of glare from the sun.
Nakagawara
Van B
VB
Federal Aviation Administration, Civil Aerospace Medical Institute, Oklahoma City, Oklahoma 73125, USA. van.nakagawara@faa.gov
Wood
Kathryn J
KJ
Montgomery
Ron W
RW
D000060:Accidents, Aviation; D026661:Clinical Trials Data Monitoring Committees; D019466:Glare / Q000009:adverse effects*; D006801:Humans; D013472:Sunlight / Q000009:adverse effects*; D014786:Vision Disorders / Q000209:etiology*