title: Aircraft and related factors in crashes involving spatial disorientation: 15 years of U.S. Air Force data.
abstract: BACKGROUND
  Previous studies have determined that spatial disorientation (SD) causes 0.5-23% of aircraft crashes, but SD-related crash and fatality rates in different aircraft types have not been systematically studied.
  
  
  METHODS
  SD crashes for the fiscal years 1990 to 2004 and aircraft sortie numbers for all U.S. Air Force (USAF) aircraft were obtained from the USAF Safety Center. Contingency table analysis and Chi-squared tests were used to evaluate differences in SD rates.
  
  
  RESULTS
  SD accounted for 11% of USAF crashes with an overall rate of 2.9 per million sorties and a crash fatality rate of 69%. The SD rate was higher in fighter/attack aircraft and helicopters than in training and transport aircraft. The risk of SD was increased at night with 23% of night crashes being caused by SD. But the SD rate and crash fatality rate were not higher in single-crewmember aircraft.
  
  
  CONCLUSIONS
  SD risk is significantly increased in helicopters and fighter/attack aircraft and at night. The data suggest that a second crewmember does not protect against SD. Further study of specific SD scenarios could lead to focused interventions for SD prevention.
authors.affiliation: Asian Office of Aerospace Research and Development, Tokyo, Japan. lyonst@aoard.af.mil
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Lyons
authors.forename: William
authors.initials: W
authors.lastname: Ercoline
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Toole
authors.forename: Kevin
authors.initials: K
authors.lastname: Grayson
mesh_terms: D000060:Accidents, Aviation / Q000706:statistics & numerical data*; D000401:Aircraft; D003221:Confusion; D004867:Equipment Design; D006801:Humans; D008889:Military Personnel / Q000706:statistics & numerical data; D009949:Orientation / Q000502:physiology; D013028:Space Perception; D014481:United States