FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-71/34

Title and Subtitle: Alcohol and disorientation-related responses. IV. Effects of different alcohol dosages and display illumination on tracking performance during vestibular stimulation

Report Date: July 1971

Authors: Gilson RD, Schroeder DJ, Collins WE, Guedry FE

Abstract: A previous CAMI laboratory investigation showed that alcohol impairs the ability of men to suppress vestibular nystagmus while visually fixating on a cockpit instrument, thus degrading visual tracking performance (eye-hand coordination) during angular acceleration. Reduced display illumination, independently, has also been shown to degrade tracking performance during vestibular stimulation.

The present study investigated the way in which low and moderate dosages of alcohol and two levels of instrument-display illumination combined to affect tracking performance (a) in a static (no motion) environment, and (b) in a dynamic (whole-body motion) environment. Mean blood alcohol levels as low as .027 per cent significantly decreased (P.05) tracking performance during whole-body motion, yet caused little change in performance in a stationary environment. Impairment was much more pronounced with dim display lighting (0.1 ft-L) than with bright lighting (1.0 ft.-L).

These results suggest that serious problems may be encountered by the pilot who drinks even lightly and who considers flying, especially at night.

Key Words: Alcohol, Performance, Nystagmus, Angular Acceleration, Vestibular, Illumination Level

No. of Pages: 12