, pronounced 'GEE-lock', is the abbreviation of G-force induced Loss Of Consciousness
, a term generally used in aerospace physiology
to describe a loss of consciousness occurring from excessive and sustained g-forces
draining blood away from the brain causing cerebral hypoxia
. The condition is most likely to affect pilots
of high performance fighter
aircraft or astronauts
but is possible on some extreme amusement park rides
. G-LOC incidents have caused fatal accidents in high performance aircraft capable of sustaining high g
for extended periods. High-G training
for pilots of high performance aircraft or spacecraft often includes ground training for G-LOC in special centrifuges
, with some profiles exposing pilots to 9 g
s for a sustained period. Such centrifuges are made by AMST Systemtechnik in Austria (Austria Metall SystemTechnik), Latacoere in France, the Environmental Tectonics Corporation (ETC) and Wyle Laboratories in the USA.
Effects of g-forces
Under increasing positive g
-force, blood in the body will tend to move from the head toward the feet. For higher intensity or longer duration, this can manifest progressively as:
- Greyout - a loss of color vision
- Tunnel vision - loss of peripheral vision, retaining only the center vision
- Blackout - a complete loss of vision but retaining consciousness.
- G-LOC - where consciousness is lost.
(Under negative g
, blood pressure will increase in the head, running the risk of the dangerous condition... Read More