Dynamic strength capabilities of small-stature females to eject and support added head weight.

BACKGROUND Naval Air Warfare Center Aircraft Division investigated the abilities of small-stature females (< or = 120 lb) to fly under G-stress using the Dynamic Flight Simulator (DFS) and its tactical fight/attack cockpit, displays and controls. OBJECTIVES Determine ability to exert NACES ejection seat actuation pull force under static, acceleration and simulated flight conditions; support up to 5 lb of added head weight (AHW) under catapult, arrestment, and aerial combat maneuver G-loads; and reach all controls. METHODS Seven female subjects (six small and one medium stature) participated. The AHW task included three helmet weights, 3.5 lb (standard configuration), 4.25 lb and 5 lb and subjects were tasked to accurately read cockpit displays. Muscular exertion and fatigue (arm, shoulder, neck) assessment used electromyography (EMG). Limits in overall reach and throttle and stick movements were measured. RESULTS Subjects successfully ejected using a two-hand grip under G-stress. Subjects read all displays supporting 5 lb under +6 Gz. Most small-stature subjects could not fully support their heads wearing 3.5 lb helmet during flat spin conditions. CONCLUSIONS Within the scope of these tests, small-stature subjects demonstrated the strength to safely initiate ejection during severe physically-taxing dynamic conditions but had difficulty supporting AHW under -Gx stress. Human factors deficiencies were noted in the areas of torso harness fit, inertia reel placement relative to shoulder width, and the ability maintain a full range of stick motion.