G-induced loss of consciousness: retrospective survey results from 2259 military aircrew.
BACKGROUND
Prevalence of G-induced loss of consciousness (G-LOC) in the United Kingdom Royal Air Force (RAF) was found to be 19.3% in 1987. With the introduction of the Typhoon, a fourth generation aircraft, the prevalence of G-LOC has been re-assessed to determine the effectiveness of current G tolerance training.


METHODS
A survey was sent to 4018 RAF aircrew, irrespective of their current role. Information was requested on G-LOC, role and aircraft type, experience, and attitudes toward G-LOC prevention.


RESULTS
Responses were received from 2259 (56.2%) individuals, 882 (39%) of whom were current fast jet aircrew. At least one episode of G-LOC was reported by 20.1% of all respondents. In front line aircraft, prevalence of G-LOC among the 882 fast jet aircrew who responded was 6%. In the whole group, G-LOC was reported most commonly in aircrew under training (70.9%), and was most prevalent in training aircraft (77.4% of G-LOC events). At the time of the G-LOC, 64% of aircrew had less than 100 h total flying time. G-LOC was reported most frequently between +5 to +5.9 Gz, and "push-pull" maneuvers were associated with 31.3% of G-LOC events. Pulling G was not considered a problem by 50.6% of respondents, although over 80% recognized the value of flying currency, use of an anti-G suit, and physical fitness, and 55.6% felt that centrifuge training would be valuable.


CONCLUSIONS
The prevalence of G-LOC in the RAF has changed little since 1987, and there remains considerable scope for aircrew education, particularly with the introduction of the Typhoon.
Green
Nicholas D C
ND
RAF Centre of Aviation Medicine, RAF Henlow, Bedfordshire, UK. hlw-cam-avmedspr@henlow.raf.mod.uk
Ford
Steven A
SA
D000328:Adult; D000337:Aerospace Medicine; D016009:Chi-Square Distribution; D005676:Gravity Suits; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000706:statistics & numerical data*; D015995:Prevalence; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014474:Unconsciousness / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D006113:United Kingdom / Q000453:epidemiology