Christensen said if Leeward were conscious, he would have cut power back once he gained altitude.
"Altitude is sanctuary," he said. "And his nose didn't hang, it came over like he was doing almost a loop ... and
when his nose came down he started gaining air speed," Christensen added. "This guy had the power up."
Rough calculations by experts using video of the plane seconds before the crash indicate it might have been
traveling at more than 400 mph when it suddenly went vertical, abruptly exerting 11 times the normal force of
gravity on the pilot's body, or 11 Gs, knocking him unconscious as the blood rushed from his brain.
By comparison, Christensen said, F-16 fighter pilots, who wear special suits to counter the G-forces, can
typically take 9 Gs, but only for a limited time. And those are modern planes designed with tilted seats intended
to help keep blood flow to the brain.
Average roller coasters expose riders to about 2 to 3 Gs, but only for brief moments.
Ken Liano, a structural engineer and aircraft consultant, said "it's highly doubtful" Leeward was awake.
"My first thought when I saw the video was there's no way that pilot is in control," Liano said. "He went from
horizontal to vertical so abruptly. No pilot would do that. Even an acrobatic pilot would probably not do that maneuver."
Liano speculated the loss of the trim tab started the sequence of events. Leeward's World War II-era plane was
highly modified for speed, much like other aircraft at the races. But the plane wasn't originally designed that way,
so the extra speed gained from the modifications likely stressed the structure, causing the failure, he said.
"Eleven Gs is a lot," said Dr. Daniel Foster, an active duty flight surgeon at Pensacola Naval Air Station in Florida.
"It probably would have been very difficult for him to maintain consciousness."
He said fighter pilots train to combat the G-forces using abdominal exercises, among other things, to keep the blood
in their heads. Typically, as the forces increase, Foster said, symptoms will gradually appear, such as nausea, faintness,
then cloudy vision, and there's time to work to counteract the impact on the body.
But if the extreme acceleration comes on suddenly, and is prolonged, such as the case with Leeward,
"it can be very rapid," Foster said. "You'd go from zero to unconscious."
