Effects of a Low Blood Alcohol Level on Pilot Performance

Pilots and non-pilots were tested on simulator flying tasks after attaining a .04% blood alcohol concentration and after ingestion of placebo drinks. Half of the pilots and half of the non-pilots were blind with respect to the contents of their drinks while half were informed. Two turbulence conditions were employed, and subjects were instructed to scan for aircraft silhouette targets that appeared on monitors in front and to the sides of the subject. The subject's task was to maintain straight and level flight, with the pilots given an additional flight segment during which the simulator's instruments and external horizon display gradually indicated an unusual attitude, either a banked steep climb or banked steep descent, while the subject was performing other tasks such as copying weather information or changing radio settings. Head movements, control movements, time to detect targets, and simulator flight measures were digitized and computer recorded and analyzed. Alcohol affected the performance of pilots and non-pilots on several performance measures during straight and level flight. The performance of pilots during the divided attention unusual attitude flight segment was such that unsafe flight conditions would have resulted.