Conclusion At relatively mild spiral descents with descent rate around 13 [m/s] a G-load of more than 3.2 G is reached. G-load increases with descent rate. Risk of G-LOC can’t be denied. It may be assumed that recent fatal incidents during the spiral descent are caused by G-LOC.
G-LOC explained Means: “G-load induced Loss Of Consciousness” G-load forces the blood away from the head, no matter how hard the heart may work. Oxygen and nutrition supply is interrupted. Eyes and brains cease functioning.
G-tolerance Average value for normal healthy human beings: 4.5 G GLOC can occur anywhere between 2 and 6.5 G. A student F16 pilot went out at 2G.
G-LOC symptoms Grey-out (loss of color in vision) Tunnel vision (field of vision narrows) Blackout (no vision any more) Loss of consciousness Brain death
Factors which contribute to a decrease in G-tolerance Any illness, even a minor cold. Chronic or acute hypotension. (low blood pressure). Most medicaments. fatigue. Non-illegal drugs (alcohol, caffeine). Dehydration (shortage on drink). Hypoglycemia (shortage on food). Stress.
Factors which contribute to a decrease in G-tolerance The last 5 bullets are typical circumstances during a week of paragliding !!!!!
What to do when you notice one of the symptoms. Stop spiraling immediately. Keep your breath and tension all your muscles (this will provide you a couple of extra seconds). Don’t try straining techniques like a fighter pilot (this requires long and repeated training. Incorrectly performed shall worsen your situation).
Recommendations Organize training program for instructors and pilots. Instructors should be trained to make sure they can relay this knowledge to their students. Pilots have to be informed. This knowledge should be included to pass the paraglider license examination.