(AP) RENO, Nev. - Air race pilots should take their modified aircraft on a dry run before participating in certain types of competitions, and should possibly wear flight suits to help them withstand high gravitational forces, according to the National Transportation Safety Board.
The recommendations were among seven the board offered during a news conference in Reno on Tuesday, in the wake of a Sept. 16 crash at the Reno National Championship Air Races that killed 11 people and seriously injured more than 70 spectators.
"We are not here to put a stop to air racing," said NTSB Chairman Deborah Hersman. "We are here to make it safer."
Investigators are still trying to piece together exactly why 74-year-old Jimmy Leeward's souped-up P-51 Mustang rocketed straight up before pitching nose first onto the tarmac just feet from a VIP viewing area. Officials say that technical finding could take months.
The NTSB said telemetry data shows the plane was traveling at 530 mph when it pitched violently upward, exerting a force of at least nine times the normal force of gravity on the pilot's body, or 9 Gs.
The NTSB said that appears to have incapacitated the pilot as blood rushed from his brain.
By comparison, experts say, 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.
Leeward was not wearing a special G-suit as he piloted the World War II-era aircraft.
Average roller coasters expose riders to about 2 to 3 Gs, but only for brief moments.
"Our investigation found that this pilot in this airplane had never flown this fast on this course," Hersman said.
The board recommends that race organizers provide training to pilots on how to mitigate the effects of high G-forces. Board members also want organizers to see whether it's feasible to require the flight suits during the races
Officials say Leeward's plane, the "Galloping Ghost," was heavily modified and had never been flown as fast as he was racing it that day on that course. To ramp up the aircraft's speed, the plane's wingspan had been shortened from about 37 feet to about 29 feet, and flight controls were changed.
The safety board recommends aircraft owners flying in the "unlimited class" provide an engineering evaluation when they race a plane with major modifications.
The Reno Air Racing Association is moving ahead with plans to hold the event this fall at Reno Stead Airport.
The recommendations will also be helpful to organizers of other air shows as the aerial events season begins, NTSB spokesman Nicholas Worrell said.
The Reno Air Races, however, is the only event of its kind, where planes of various categories fly wing-tip-to-wing-tip around an oval, aerial pylon track, sometimes just 50 feet off the ground and at speeds that can top 500 mph.