Research was conducted on pilot stress during simulated emergency flight conditions. Catecholamine (adrenaline and non-adrenaline) secretion for twenty United States Air Force student pilots and thirteen instructor pilots was determined during daily activities, during simulated flights performed in high realism simulators, and during actual flight. High realism simulation resulted in a measurable stress response in both students and instructors; the response was not related to previous flight experience. One group of students experienced power-on stalls and spin recoveries in the simulator prior to their introduction in the aircraft. A second group of students experienced power-on stalls and spin recoveries in the aircraft prior to their introduction in the simulator. Catecholamine secretion during simulation was not different for the two groups, thus aircraft exposure to the spin series did not alter the stress response of the students attempting a similar maneuver in a high realism simulator. Task-specific high realism simulation introduced prior to exposure to related, stressful in-flight tasks results in similar total stress response, but somewhat lower arousal and greater mental activity. A comparison of superior and inferior students within each group suggested that the simulator pretraining had the greatest effect on the inferior students. There was a significant negative relationship between student performance and instructor stress during the initial aircraft power-on stall and spin-recovery sortie. (Author/CT)