Issues and Knowledge Concerning the Use of Head-Up Displays in Air Transports

This document provides a literature review of design issues encountered by the Federal Aviation Administration (FAA) during the certification of head-up displays (HUDs) for use in air transports. This review extracts certification advice from the literature and necessary to provide more complete certification guidelines for HUDs. There are four categories of design issues: information accessibility (clutter), task-display compatibility,display consistency,and physiological effects. There is substantial research on clutter-related issues, especially with regard to interference with the out-the-window view. However, while qualitative certification advice can be drawn from these studies,there is a need for a more systematic means to determine an acceptable between accessible flight information and clutter.There is also substantial knowledge on the task display compatibility issues, especially concerning unusual attitude recovery. However, important benefits would be realized from the development of monochrome coding conventions for information such as alert levels. Research is needed on display consistency, especially regarding the effects of differences between the dead down and HUD layouts and formats. Likewise, the effects of hud hardware design on pilot physiological stress and performance require study. For example, the amount of head motion a HUD must allow for is unknown.