title: Pilot Domain Task Experience in Night Fatal Helicopter Emergency Medical Service Accidents.
abstract: BACKGROUND
  In the United States, accident and fatality rates in helicopter emergency medical service (HEMS) operations increase significantly under nighttime environmentally hazardous operational conditions. Other studies have found pilots' total flight hours unrelated to HEMS accident outcomes. Many factors affect pilots' decision making, including their experience. This study seeks to investigate whether pilot domain task experience (DTE) in HEMS plays a role against likelihood of accidents at night when hazardous operational conditions are entered.
  
  
  METHODS
  There were 32 flights with single pilot nighttime fatal HEMS accidents between 1995 and 2013 with findings of controlled flight into terrain (CFIT) and loss of control (LCTRL) due to spatial disorientation (SD) identified. The HEMS DTE of the pilots were compared with industry survey data.
  
  
  RESULTS
  Of the pilots, 56% had ≤2 yr of HEMS experience and 9% had >10 yr of HEMS experience. There were 21 (66%) accidents that occurred in non-visual flight rules (VFR) conditions despite all flights being required to be conducted under VFR. There was a statistically significant increase in accident rates in pilots with <2 and <4 yr HEMS DTE and a statistically significant decrease in accident rates in pilots with >10 yr HEMS DTE.
  
  
  CONCLUSIONS
  HEMS DTE plays a preventive role against the likelihood of a night operational accident. Pilots with limited HEMS DTE are more likely to make a poor assessment of hazardous conditions at night, and this will place HEMS flight crew at high risk in the VFR night domain.
authors.affiliation: Department of Aviation, Faculty of Science, Engineering and Technology, Swinburne University, Hawthorn, Victoria, Australia.
authors.forename: Bryan B
authors.initials: BB
authors.lastname: Aherne
authors.forename: Chrystal
authors.initials: C
authors.lastname: Zhang
authors.forename: David G
authors.initials: DG
authors.lastname: Newman
mesh_terms: D000060:Accidents, Aviation / Q000401:mortality / Q000706:statistics & numerical data*; D000328:Adult; D000337:Aerospace Medicine; D000368:Aged; D017732:Air Ambulances; D001359:Aviation; D003430:Cross-Sectional Studies; D004632:Emergency Medical Services / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011361:Professional Competence; D013997:Time Factors; D014481:United States / Q000453:epidemiology