In spite of an immense increase in interest in helmet-mounted displays (HMDs) over the past two decades, there have been few studies on head motion while using HMDs in operational flight. Rotary-wing flights conducted using a number of HMD configurations have resulted in a head position database what will be useful in filling this void. Various analysis techniques have been applied to investigate characteristics of roll (tilt) head position distributions for a slalom flight maneuver for four visual environments: good visual environment (daytime, unaided), night vision goggles, HMD with thermal imagery, and HMD with thermal imagery and symbology
Helmet-mounted displays (HMDs), while not new, are a unique method of providing pilotage and targeting imagery to aviators. Although there are a number of HMDs in various phases of design, the AH-64s Integrated Helmet and Display Sighting System (IHADSS) is currently the Army's only fielded integrated HMD. A number of studies have investigated the visual and perceptual issues associated with the monocular optical design of the IHADSS in combination with the AH-64s forward looking infrared (FLIR) thermal sensor (Pilots Night Vision System - PNVS). While these systems have greatly enhanced the operational effectiveness of the AH-64, they have resulted in reports of physiological complaints, degraded visual cues, and both static and dynamic illusions. This study investigated the possible role the IHADSS HMD and PNVS may have played in AH-64 Apache accidents. A total of 217 AH-64 accidents (FY85-02) were analyzed and assigned causal factors associated with the use of the IHADSS and PNVS. The resulting analysis failed to identify any significant role between these systems and flight-related accidents.
The Integrated Helmet and Display Sighting System (IHADSS), employed in the U.S. Army's AH-64 Apache helicopter, is used to present pilotage and targeting imagery and symbology. Therefore, in addition to the standard comfort and protection requirements of a helmet system, the IHADSS must provide a stable optical alignment. Fielded in the early 1980's, the IHADSS is still the Army's only integrated helmet-mounted display (HMD). In an attempt to perform both the standard protective role of a helmet and to serve as a mounting platform for an optical sight, the IHADSS had to make certain design compromises that have resulted in some user satisfaction issues. A joint survey of U.S. and U.K. AH-64 aviators was conducted to identify and quantify these issues. Survey findings indicated that while a majority of aviators found the quality, comfort and satisfaction of fit to be acceptable, a significant proportion of aviators have encountered problems associated with obtaining proper helmet size, availability of replacement components, and substantial variation in fitting expertise. Results of this survey can assist in ongoing and future HMD helmet system designs.