Helmet Mounted Display (HMD) Symbology for Rotocraft Degraded Visual Environments

“Brownout” is a dangerous phenomenon in which a rotorcraft’s downwash creates its own degraded visual environment (DVE) by throwing dust, sand, and other loose debris into the air around the aircraft, severely limiting or obscuring the pilots’ view of the landing environment. During a recent fiscal year, the U.S. Army determined that 75% of aviation Class A mishaps in Operation Iraqi Freedom were attributed to this phenomenon. The objective of this research effort is to determine the feasibility of integrating symbology into a helmet-mounted display (HMD) to aid rotorcraft pilots in day/night brownout/DVE conditions, and identify the steps needed to develop this technology for aviation applications. The feasibility of such an approach depends on the development of effective, intuitive HMD symbology that provides the pilot with the data required to facilitate rotorcraft landing operations. One of the challenges of this development will be determining and mitigating the effects of the expected wide variations in day/night brownout/DVE background condition against which the HMD symbology will be viewed. HMD display symbology for this application must provide high contrast against the background, with low intensity and eye strain, particularly with night vision devices.