A Human Performance/Workload Evaluation of the AN/PVS-5 Bifocal Night Vision Goggle

Eight experienced US Army aviators performed various maneuvers in an instrumented helicopter to test the relative usability of two bifocally configured night vision goggles. Both configurations were statistically better than the unmodified arrangement when looking at a pilots ability to hold a precise altitude at night. The subjective data, supported by flight performance observed between the two bifocals, further suggested that a 24 bifocal version was more desirable than a 14 configuration. The inference is that the reduced inside field-of-view presented by the 14 bifocal interferes with a pilots ability to rapidly locate instruments once he has directed his attention inside the cockpit.