High Speed Blackouts Are Deadly
The U.S. Air Force recently revealed that an F-16 pilot, killed when his aircraft dove into the ground during an air combat training exercise, appears to have passed out because high G-forces while making a high-speed turn at 6,000 meters (18,000 feet). Fighter pilots are equipped and trained to deal with handling up to 9 Gs. But some of these methods require the pilot to contract abdominal muscles and take a deep breath to maintain consciousness.
See the full article at Strategy Page