No abstract

No abstract

Ownship status helmet-mounted display (HMD) symbology for off-boresight use in fixed-wing tactical aircraft serves to convey aircraft state information (e.g., airspeed, heading, altitude, and attitude) to the pilot for increased situation awareness and maintenance of spatial orientation. A recent flight test evaluation of HMD symbology conducted by the Air Force Research Laboratory (AFRL) and the Edwards AFB Test Pilot School (TPS) indicated a clear performance advantage afforded by the use of off-boresight symbology compared to HUD use alone. The results indicated that the Non-Distributed Flight Reference (NDFR) was the best format of the HMD symbol sets evaluated and served as a good information/orientation aid off-boresight but needs further development to realize its tactical benefit. Specifically, the TPS recommendations pointed to a need for an improved rate-of-change (i.e., trend) indicator for airspeed and altitude, as well as an improvement to the off-boresight attitude reference concerning attitude precision (i.e., climb-dive), particularly near straight and level flight. Based on these recommendations, AFRL modified the original design of the NDFR symbology to satisfy the deficiencies noted by the Edwards AFB TPS. Two variants of the NDFR format with modifications for conveying trend information for airspeed and altitude as well as precision of aircraft attitude were evaluated along with the Mil-Std-1787C HUD symbology and baseline NDFR format. The study examined the four symbol sets during two simulated operationally representative air-to-air intercept tasks that employed the use of an HMD for the off-boresight visual acquisition of a target aircraft. Overall, the NDFR/Odometer symbology allowed a significantly higher amount of off-boresight viewing time while equaling the HUD and other off-boresight symbol sets for primary task performance and proved to be the preferred format for trend mechanization based on pilot comments.