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.
Nigerian Air Force MiG-21 pilot black out
Isaac Alfa, former Nigerian Air Force MiG-21 Fishbed pilot, recalls on Quora;
‘I was in an air display and I was flying the solo display aircraft, flying a MiG-21.
‘I came too low over the display stadium at a very high speed and had to scale very tall floodlight masts on my path. Then I had to hit the after burner, pulling the joy stick all the way back to my stomach. I momentarily blacked out from extreme g-forces. I can’t explain how I was able to quickly regain consciousness, but I was lucky to be flying a rugged aircraft. If the aircraft had stalled from the extreme g-forces, that would have been it.
‘Extreme g-forces can blackout the pilot, causing loss of consciousness, stall, flame-outs, etc, leading to crash and death. However, most modern fighter jet aircraft are equipped with fly-by-wire control systems that ensure automatic manoeuvre envelope protection. No matter how hard or violently you pull on the Control, the system keeps the aircraft within the safe flight envelopes.’
Photo by U.S. Air Force
