Australian meteorologist Grant Denyer went for a joyride with Red Bull air race pilot Matt Hall the other day, jonesing for an adrenaline rush. “Eight Gs,” Denyer begged Hall, after breezing through some four-G maneuvers. A few seconds after Hall began wrenching the airplane up one wing, then the other, knife-edge to knife-edge, Denyer’s head hit the backstop, eyes closed and down for the count. G-LOC, the pros call it: G-induced loss of consciousness.
Military pilots wear G-suits and/or tense their muscles to prevent blood from draining from the torso, but civvies are on their own, and rarely make it through six Gs, let alone eight. At six Gs, your vision begins to “gray out,” narrowing to a tunnel as blood drains from your head. It can take several seconds for pilots and joyriders to wake up from their involuntary nap, and several more seconds to realize where they are, which is why G-LOC can be deadly. Even more uncomfortable is the onset of negative Gs, when you “red out” from the blood rushing to your head. Pilots and airplanes can cope with only fairly light negative-G force — maybe one half of the positive G-load they can withstand.
At least Denyer wasn’t caught drooling on camera, something I fear when I doze off on a commercial flight.