title: The "push-pull effect" and G-induced loss of consciousness accidents in the U.S. Air Force.
abstract: BACKGROUND
  A recent Canadian Forces CF-18 Hornet aircraft accident has focused interest on the push-pull effect (PPE). PPE has not previously been identified in U.S. Air Force (USAF) G-Induced Loss of Consciousness (G-LOC) Accidents. The presence of maneuvers known to cause the push-pull effect (PPEMs) that lead to G-LOC accidents suggests that PPE is operationally significant and is a potential cause of G-LOC accidents.
  
  
  METHODS
  USAF accident reports where G-LOC was found to be causal were reviewed for indications of a PPEM immediately prior to the G-LOC. Terminology in the narratives was used to indicate a PPEM in the accident sequences.
  
  
  RESULTS
  In 3 of 24 mishaps, the presence of a PPEM was highly probable, while another 4 mishaps were found to have a probable association with PPEMs. The probable presence of PPEMs represents a significant percentage (12.5-29%) of USAF G-LOC accidents.
  
  
  CONCLUSIONS
  USAF G-LOC accident reports contained descriptions that indicated the presence of PPEMs in accident sequences. This finding suggests that the PPE is an operationally significant source of risk for accidents in USAF high-performance aircraft.
authors.affiliation: U.S. Air Force School of Aerospace Medicine, Brooks Air Force Base, TX 78235-5252, USA.
authors.forename: V J
authors.initials: VJ
authors.lastname: Michaud
authors.forename: T J
authors.initials: TJ
authors.lastname: Lyons
mesh_terms: D000054:Acceleration / Q000009:adverse effects*; D000060:Accidents, Aviation / Q000517:prevention & control / Q000706:statistics & numerical data* / Q000639:trends; D000337:Aerospace Medicine; D006112:Gravitation; D006801:Humans; D008889:Military Personnel; D012307:Risk Factors; D014474:Unconsciousness / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D014481:United States / Q000453:epidemiology