A NEW UNDERSTANDING OF THE EFFECTS OF +G

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Authors
  1. Banks, R.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
G-induced loss of consciousness (G-LOC) remains a killer in aviation. A vector quantity usually expressed as "G", acceleration stress is experienced by aircraft occupants whenever the aircraft changes speed or direction. Any increase in the magnitude of this vector is termed increased positive Gz (+Gz). Under increased +Gz, blood pressure at head level can decrease to the point that blood flow in the brain stops. When blood flow stops, brain function is possible for only several seconds before G-LOC occurs. When G-LOC occurs to a pilot in control of an aircraft, the result is often catastrophic. A significant amount of flying involves +Gz following relative -Gz. Reduced +Gz tolerance following relative -Gz has been demonstrated. A loss of +Gz tolerance was termed the "push-pull effect". This effect has been found causal in at least two aircraft accidents. The role of +Gz time-history in determining +G tolerance should be understood by all pilots and those involved in design. Protective systems and strategies must be designed to account for the preceding baseline, particularly in an era of advanced technology aircraft designed to perform complex acceleration profiles. Through education and technology development, human and aircraft losses due to G-LOC can be prevented.
Keywords
G-LOC;Gravity-induced loss of consciousness;G-protection;G-suits;Positive pressure breathing (PPB)
Report Number
DCIEM-96-P-26 — Reprint
Date of publication
03 Sep 1996
Number of Pages
3
Reprinted from
Canadian Aeronautics and Space Journal, vol 42, no 3, 1996, 3p
DSTKIM No
97-00215
CANDIS No
500389
Format(s):
Hardcopy;Document Image stored on Optical Disk

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