Human error has been found to cause or contribute to most aviation accidents. Excess emotional stress may have an adverse effect on pilot performance and is known to increase the risk of an aircraft mishap. Family problems, social stressors, career instability, worry, aircraft accidents, and difficult flight schedules are a few of the many potential sources of emotional stress in aviation. Pilots who fail at stress coping may become depressed or even self-destructive. They may externalize their feelings, act out, or blame others for their misfortunes. The aviator at risk may demonstrate "warning signs" such as defensiveness, arrogance, hostility, financial irresponsibility, excesses in routine habits, fatigue, deteriorating pilot performance, or increased risk taking. The aeromedical practitioner's role is to educate aircrew members and help them understand stress and its effect on pilot performance. The time may come when an aviator is confronted by multiple stressors, and inadequate stress coping or failure on the part of the aviation community to recognize the "warning signs" may have disastrous results.