THE OPTOKINETIC CERVICO REFLEX DURING SIMULATED HELICOPTER FLIGHT

Introduction: The optokinetic cervico reflex (OKCR) is a recently hypo thesized, visually driven reflex that serves to stabilize die image of the external horizon on the retina during roll maneuvers in high-perf ormance aircraft. Although reported anecdotally, head tilt during heli copter flight has not been studied formally. Such research is required to determine the full impact and significance that it may have on the flying performance of a rotary-wing aviator. Objective: The aim of th is study was to investigate the relationship between horizon position and the perception of orientation and, thus, to generate vital informa tion to assess whether OKCR plays an important role in spatial disorie ntation. Hypothesis: Pilots of rotary-wing aircraft will exhibit the O KCR. Methods: A UH-60 flight simulator study, with 20 volunteer pilots participating, was performed to examine the effects of this reflex du ring day flight and during flight with night vision goggles (NVGs). Re sults: The results confirm that the OKCR occurs during simulated helic opter flight, both with and without NVGs. As with previous studies, he ad roll increased during flight under visual meteorological conditions in relation to an increasing aircraft roll angle up to a maximum sust ainable level and then remained constant. Head roll did not occur duri ng night under instrument meteorological conditions. Conclusion: The p resence of the OKCR will impact rotary-wing operations. Various aspect s are discussed, and recommendations are made for future research.