The usage of conformal symbology in color head-worn displays (HWDs) opens up a range of new possibilities on modern flight decks. The capability of color augmentation seems especially useful for low flights in degraded visual environments. Helicopter flights in these conditions, including brownout by swirling dust or sand particles, can often lead to spatial disorientation (SD) and result in a significant amount of controlled flight into terrain (CFIT). While first generation color-capable conformal displays are deployed, practical guidelines for the use of color in these see-through interfaces are yet to be established. A literature survey is carried out to analyze available knowledge of color use in conformal displays and to identify established methodologies for human-factors experimentation in this domain. Firstly the key human factors involved in color HWDs are outlined, including hardware design aspects as well as perceptual and attentional aspects. Secondly research on color perception is mapped out, focusing on investigations of luminance contrast requirements, modeling of color space blending and development of color correction solutions. Thirdly application-based research of colored conformal symbology is reviewed, including several simulations and flight experiments. Analysis shows that established luminance contrast requirements need to be validated and that performance effects of colored HWD symbology need more objective measurements. Finally practical recommendations are made for further research. This literature study has thus established a theoretical framework for future experimental efforts in colored conformal symbology. The Institute of Flight Guidance of the German Aerospace Center (DLR) anticipates conducting experiments within this framework.
In the past couple of years, research on display content for helicopter operations headed in a new direction. The already reached goals could evolve into a paradigm change for information visualization. Technology advancements allow implementing three-dimensional and conformal content on a helmet-mounted see-through device. This superimposed imagery inherits the same optical flow as the environment. It is supposed to ease switching between display information and environmental cues. The concept is neither pathbreaking nor new, but it has not been successfully established in aviation yet. Nevertheless, there are certainly some advantages to expect—at least from perspective of a human-centered system design. Within the following pages, the next generation displays will be presented and discussed with a focus on human factors. Beginning with recalling some human factor related research facts, an experiment comparing the former two-dimensional research displays will be presented. Before introducing the DLR conformal symbol set and the three experiments about an innovative drift, indication related research activities toward conformal symbol sets will be addressed.