Visual issues associated with the use of the Integrated Helmet and Display Sighting System (IHADSS) in the Apache helicopter - Three decades in review

In the late 1970s the U.S. Army developed the Integrated Helmet and Display Sighting System (IHADSS)(a), which is a helmet-mounted display (HMD) for use in the AH-64 Apache helicopter. The helicopter and the system were designed with the Cold War in mind such that the Apache would be able to stand off far from the frontlines and attack deep targets - primarily tanks - before they could engage our ground forces. The design used a right-sided monocular display optical system that was intended to reduce head-supported weight. This novel monocular design introduced a number of issues that had the potential of causing visual perception problems for pilots. Since the initial fielding of the Apache in the early 1980s, numerous reports have appeared in the literature that evaluated realized visual complaints voiced by Apache aircrew. In this review, the authors provide a summary of seminal reports, surveys, and experiments conducted over the past three decades. The extant literature described investigated these visual issues as the Apache's mission has evolved from the stand-off engagement tactics of the Cold War to the new Apache missions of close air support, deep attack, and raids currently occurring in the Global War on Terrorism.