nearly half of the pilots, intelligence coordinators, and sensor operators of remote piloted aircraft flying in combat in Southwest Asia report high levels of stress and exhaustion, these symptoms are more often linked to their long, erratic schedules rather than exposure to combat, according to a recent Air Force study. Conducted between 2009 and 2011, researchers at USAF's School of Aerospace Medicine at Wright-Patterson AFB, Ohio, surveyed more than 800 MQ-1 Predator, MQ-9 Reaper, and RQ-4 Global Hawk pilots and sensor operators. Forty-six percent of Predator and Reaper pilots reported "high operational stress," while 41 percent of sensor operators and 39 percent of intelligence coordinators reported the same. Forty-eight percent of Global Hawk sensor operators reported high stress as did 44 percent of RQ-4 pilots. Identified as main causes of the stress were long hours, frequent shift changes, low manning, and the "mind numbing" task of sustaining vigilance over endless hours of sensor feeds, according to the study's findings. Among the study's recommendations are the optimization of work and rest cycles as well as shift rotations. (Study full document and stress screening presentation; caution, large-sized files.)