G-LOC
G-induced Loss Of Consciousness (abbreviated as G-LOC) is 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 and aerobatic 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 Gs for a sustained period.
Nevertheless, only a few fighter pilots have experienced G-LOC incidents.
How high Gs over many years damage a fighter pilot’s body
But do repeated exposures to high Gs over many years have long term negative effects on a fighter pilot’s body?
John Chesire, former US Navy F-4 Phantom II and F-14 Tomcat pilot, explains on Quora;
‘I had a CAT Scan or an MRI a few years ago for something else. Part of it showed a lot of degenerative arthritis and damaged discs in my neck.
‘The doctor reviewing the results said, “Whatever did you do to your neck?” I responded, “I once was a fighter pilot.” He replied, “Well that explains it!”
‘Of course, little did he know I would also snap my neck at every lovely young lady in a short skirt who passed by me back then, so who knows the cause.
‘I do not know of other fighter guys having the same problem, but I also have never asked. I do remember one flight where I twisted my neck under high Gs and pinched a nerve in my neck. I was stunned and momentarily incapacitated. My RIO was screaming as we were nose down and almost supersonic, asking me what was going on. He almost ejected. We still talk about that decades later.
‘I have mild neck pain to this day, although I can live with it. I don’t know if it is the result of twisting and turning my neck around violently while pulling 6-Gs, or if it was the time, I dove into the Platte River in Nebraska and hit a submerged sandbar.’
Chesire concludes;
‘If I could do it all over again, would I do it? Yes, to being a fighter pilot; no to diving in the Platte River.’
U.S. Navy photo by Photographer’s Mate 2nd Class Daniel J. McLain
