This paper is a literature study of the Head Up Display (HUD) in general with focus on the HUD's role in the civil aviation industry in particular. The objective is to present the history of the HUD in brief, summarize the basic design, describe the HUD's role in today's civil aviation and present the HUD in a human factors concept. This includes describing the human information processing behavior and human spatial disorientations concerning instrument scanning techniques and the most common sensory illusions experienced. There is also a summary of HUD symbology in different phases of flight. Some of the main sources of information have been Richard L. Newman's book ?Head Up Displays: Designing the Way Ahead? (1995) and Stoke's ?Display Technology? (1990). The main conclusion is that the HUD aids the instrument scanning process in phases of flight with high workload, such as take off, approach and landing resulting in increased situational awareness, flight precision and flight safety. It also provides airlines with a cost effective alternate in reaching low visibility operations
