Disorienting effects of aircraft catapult launchings. II. Visual and postural contributions.

Gx accelerations approximating those encountered in aircraft catapult launchings were generated on the human centrifuge Dynamic Flight Simulator at the Naval Air Development Center. Each of four catapult-experienced Naval aviators continuously oriented himself to the gravitational vertical both before and after exposure to the accelerations under two conditions: a) while he sat in total darkness, and b) while he viewed a small target projected at eye level in his mid-sagittal plane. The accelerations produce changes of pitch orientation that were affected by the presence or absence of the target, and the changes of orientation persisted well after the accelerations were terminated. Visual and postural illusions and their contributions to the disorientation are discussed, and the disorientation is related to certain water-collision accidents that have been reported to occur following aircraft catapult launchings at night.