Light adaptation: night vision goggle effect on cockpit instrument reading time.
BACKGROUND
Light adaptation to the intensified image provided by a night vision device may handicap pilots who have set cockpit instrument luminance too low.


METHODS
Under conditions simulating night flying, subjects adapted to an NVG image at 3 or 10 footlamberts (fL), then used a joystick to indicate the position of the horizon in an ADI illuminated by NVIS-compatible light at luminances 2 to 3.5 log units lower than the NVG image.


RESULTS
Response times increased no more than a few tenths of a second when the decrease in luminance was only 2 log units. Greater decreases produced correspondingly longer delays in response, reaching as much as 5.5 s for subjects in their twenties and 8-15 s for older subjects.


CONCLUSIONS
While a decrease of more than 2 log units is not likely to occur under most operational conditions, it is certainly possible, and pilots should be aware that significant risk can be incurred by setting cockpit instruments to luminance levels below 0.03 fL.
Howard
C M
CM
Warfighter Training Research Division, United States Air Force Research Laboratory, Mesa, AZ, USA. Celeste.Howard@williams.af.mil
Riegler
J T
JT
Martin
J J
JJ
D000221:Adaptation, Ocular / Q000502:physiology*; D000328:Adult; D000337:Aerospace Medicine; D003198:Computer Simulation; D006804:Ergonomics; D005139:Eyeglasses / Q000592:standards*; D006801:Humans; D008875:Middle Aged; D008889:Military Personnel; D011930:Reaction Time; D011932:Reading; D012307:Risk Factors; D013997:Time Factors; D014481:United States