Stability of simulated flight path control at +3 Gz in a human centrifuge.

INTRODUCTION: Earlier studies have shown that naïve subjects and experienced jet pilots produce exaggerated manual forces when exposed to increased acceleration (+Gz). This study was designed to evaluate whether this exaggeration affects the stability of simulated flight path control.

METHODS: We evaluated naïve subjects' performance in a flight simulator which either remained stationary (+1 Gz), or rotated to induce an acceleration in accordance to the simulated flight path with a mean acceleration of about +3 Gz. In either case, subjects were requested to produce a series of altitude changes in pursuit of a visual target airplane. Resulting flight paths were analyzed to determine the largest oscillation after an altitude change (Oscillation) and the mean deviation between subject and target flight path (Tracking Error).

RESULTS: Flight stability after an altitude change was degraded in +3 Gz compared to +1 Gz, as evidenced by larger Oscillations (+11%) and increased Tracking Errors (+80%). These deficits correlated significantly with subjects' +3 Gz deficits in a manual-force production task.

DISCUSSION: We conclude that force exaggeration in +3 Gz may impair flight stability during simulated jet maneuvers in naïve subjects, most likely as a consequence of vestibular stimulation.