During the summer of 03', I was called to the Skippers' (we actually called him the Squadron Commander - but, I'm trying to learn my new vernacular) office to explain why three of my students had G-LOC'd themselves in a span of about 10 days. All three of them did it in the G-Awareness exercise or G-Warm up. Since I was flying the T-37 at the time, I sat there right next to them and watched them do it to themselves. They all three had the following in common
1. Tall and Skinny
2. Male
3. Inexperienced
4. Was during the GX maneuver at about 5 G's
5. It was exceptionally hot in Del Rio that summer and they were on their 2nd hop of the day (dehydrated and tired.)
The real culprit though, was that they were all doing the worst G-strain at the time, which is the No-strain. Because the T-37 couldn't pull a level 5-G turn, the nose had to be about 20 degrees low to get a decent 90 degree 5-G pull without losing precious airspeed. So, after their obligatory 3 good breathing cycles - they were done with the exercise and stopped straining. Problem is, the jet still needed to be pulled from the dive, and still had plenty of smash on it. So, as they continued pulling the nose to level and without straining, they went to sleep. The second kid did the best funky chicken I have ever seen and let out the most awesome little girl scream - I wish I would have had a HUD tape. I never saw this same type of thing when teaching in the T-6 or in the T-38. Perhaps, because they could pull a better GX without such a horrendous dive needed to preserve energy. Anyway, somebody pointed out experience as a big factor - and I think this really is the biggie. Knowing when and how much to strain based on attitude, airspeed, duration of pull, etc. is huge.
This stuff makes me excited to get back into it - although my G-tolerance is probably a little less than awesome right now. The 767 hasn't exactly kept me proficient.