Laboratory assessment of pilot performance using nonrated subjects at three alcohol dose levels

To evaluate the effects of drugs and environmental stresses on pilot psychomotor performance, an automated system was developed around a Link GAT 1 flight trainer. Performance was electronically scored during 1 hr simulations of cross country instrument flight, using special purpose analog and digital logic. The sensitivity of this system was assessed by observing the acute effects of 3 graded doses, 0.3, 0.6, and 0.9 gm/kg body weight, of ethyl alcohol on scored performance. Three separate experiments were conducted using a total of 22 male subjects, ages 21 to 29. Statistically significant performance decrements were observed at all 3 dose levels. These decrements were small at the low dose, showed a progressive increase with the moderate dose, and became substantial at the high dose. The corresponding indirectly measured blood alcohol levels (average of pre and posttask Breathalyzer samples) for these 3 doses were in the order of 25, 55, and 85 mg% respectively, levels well below those currently employed to define limits of legal intoxication in reference to automobile driving. Comparison tests conducted on 2 older pilot psychomotor tasks, the Multidimensional Pursuit Task (MDP) and Complex Coordinator (CC), gave fully comparable results.