title: In-Flight Study of Helmet-Mounted Symbology System Concepts in Degraded Visual Environments.
abstract: BACKGROUND
  During approach and departure in rotary wing aircraft, a sudden loss of external visual reference precipitates spatial disorientation.
  
  
  METHODS
  There were 10 Royal Canadian Air Force (RCAF) Griffon pilots who participated in an in-flight investigation of a 3-dimensional conformal Helmet Display Tracking System (HDTS) and the BrownOut Symbology System (BOSS) aboard an Advanced System Research Aircraft. For each symbology system, pilots performed a two-stage departure followed by a single-stage approach. The presentation order of the two symbology systems was randomized across the pilots. Subjective measurements included situation awareness, mental effort, perceived performance, perceptual cue rating, NASA Task Load Index, and physiological response. Objective performance included aircraft speed, altitude, attitude, and distance from the landing point, control position, and control activity. Repeated measures analysis of variance and planned comparison tests for the subjective and objective responses were performed.
  
  
  RESULTS
  For both maneuvers, the HDTS system afforded better situation awareness, lower workload, better perceptual cueing in attitude, horizontal and vertical translation, and lower overall workload index. During the two-stage departure, HDTS achieved less lateral drift from initial takeoff and hover, lower root mean square error (RMSE) in altitude during hover, and lower track error during the acceleration to forward flight. During the single-stage approach, HDTS achieved less error in lateral and longitudinal position offset from the landing point and lower RMSE in heading.
  
  
  CONCLUSIONS
  In both maneuvers, pilots exhibited higher control activity when using HDTS, which suggested that more pertinent information was available to the pilots. Pilots preferred the HDTS system.
authors.affiliation: Defence Research and Development Canada, Toronto Research Centre, Toronto, Ontario, Canada.
authors.forename: Bob
authors.initials: B
authors.lastname: Cheung
authors.forename: Gregory
authors.initials: G
authors.lastname: Craig
authors.forename: Brad
authors.initials: B
authors.lastname: Steels
authors.forename: Robert
authors.initials: R
authors.lastname: Sceviour
authors.forename: Vaughn
authors.initials: V
authors.lastname: Cosman
authors.forename: Sion
authors.initials: S
authors.lastname: Jennings
authors.forename: Peter
authors.initials: P
authors.lastname: Holst
mesh_terms: D000337:Aerospace Medicine; D000401:Aircraft / Q000295:instrumentation*; D002170:Canada; D003198:Computer Simulation; D003221:Confusion / Q000517:prevention & control*; D003626:Data Display; D006260:Head Protective Devices; D006801:Humans; D008297:Male; D008889:Military Personnel; D009949:Orientation; D013028:Space Perception; D065854:Spatial Navigation; D013647:Task Performance and Analysis