LEARNING TO DISAMBIGUATE HOVER'S VISUAL CUES

Introduction: We report the evaluation of a display designed to assist in training rotary wing hover. Hover has always been difficult to learn and simulator training has proven to be even more problematic. From the viewpoint inside the cockpit, the beginning student neither sees nor understands what needs to be done to control the aircraft. This is because in both real and simulated flight the out-the-window visual cues suffer from two primary shortcomings. First, even the real world visual cues are ambiguous. For example, the relative motion of the ground moving under the nose may indicate forward flight, pitching upward, vertical ascent, or any combination of these. Second, human ability to judge aircraft pitch by itself is insufficient to stabilize the aircraft; other clues such as relative motion or parallax must augment pitch judgments in order to set aircraft attitude adequately. Methods: Using the USAARL Microsim, the UH 60 Simulator, and Army flight students, hover skill acquisition was evaluated with the aid of a training display (TD) that is specifically constructed to communicate aircraft performance and attitude. The TD disambiguates the external world's features and motion cues into symbology that allows each cue independently to support sufficient levels of parameter resolution. Results: Our observations indicate that by eliminating cue ambiguity and attitude resolution issues, beginning student flight performance (hover hold accuracy) is improved between 200 and 400%. These observations also indicate that, once a student understands what the aircraft is doing from the TD, they can successfully control the aircraft using real world cues. Conclusion: The visual cues of external world's features and motions significantly limit hover performance for the student pilot. The TD facilitates learning to hover because it shows the student pilot how to identify, interpret, and utilize the visual cues of the external world.