RENO, Nev. (AP) -- 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, the National Transportation Safety Board said Tuesday.
The recommendations were among seven the board offered during a news conference in Reno, nearly six months after a 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 on Sept. 16.
Officials say a final report would be issued before this year's air races, scheduled for September.
Intense scrutiny will be given to those last seconds of the doomed flight, when Leeward's plane banked going around the eighth pylon on the third lap of a six-lap race. It veered back to the right, shot up and rolled over before slamming into the ground in front of horrified spectators.
"That 8 or 9 seconds is going to get a lot of written words" in the final report, said Howard Plagens, NTSB lead investigator.
The NTSB said telemetry data showed 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. Average roller coasters expose riders to about 2 to 3 Gs, but only for brief moments.
Leeward was not wearing a special G-suit as he piloted the World War II-era aircraft.
"We know very well that that is at the limit for human beings, and it is very difficult for people to maintain awareness at 5 Gs -- 9 Gs is significant," Hersman said. "But more importantly is the rapid onset in less than a second of this increased load."
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 for the fastest aircraft.
Other safety recommendations involve changes to the race course layout and where fuel trucks and spectators are located
A Houston-based attorney who represents 18 victims and family members in a lawsuit filed in Texas against the pilot's family, a mechanic on the aircraft and the Reno Air Racing Association said the recommendations were encouraging.
"There's never been a call to end air racing, but it can be done much more safely," said Tony Buzbee, whose lawsuit seeks tens of millions of dollars in damages.
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 recommended that aircraft owners flying in the "unlimited class" provide an engineering evaluation when they race a plane with major modifications and test it out before the day of the event. "Our investigation found that this pilot in this airplane had never flown this fast on this course," Hersman said.
The NTSB also called on the Federal Aviation Administration to correct what it said were numerous errors and discrepancies in its guidance for race course designs, including the distance that spectators should be from the edge of the course.
While some FAA materials call for the primary spectator area to be 500 feet from edge of the course, another FAA document specifies the distance should be 1,000 feet for the unlimited class like the one Leeward was competing in and doesn't distinguish between the primary spectator area and spectators in general.
Seating at the Reno Air Races met the 500-foot requirement but not the 1,000-foot cushion.
Mike Houghton, Reno Air Racing Association president, said he was unaware of the distance discrepancy. "I've never seen any documents that suggest 1,000 feet," he said.
The FAA was already acting on the NTSB recommendation, the agency said. The FAA was adopting a standardized national accreditation program for air races, according to an agency statement. An FAA team will conduct review of the association's operations, the race course and proposed spectator areas, the statement said.
Hersman said it's possible that putting more distance between the planes and the spectators could have helped, but stopped short of saying the tragedy could have been prevented by such a change. "I don't think we can say what the outcome would have been," she said.
The association's event at Reno Stead Airport is the only event of its kind, where planes 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.
Houghton said most of the NTSB recommendations were "doable," and said G-force training for pilots has been implemented. But he questioned the feasibility of G-suits for the unlimited class pilots because of the cramped quarters in the modified planes and expense. Such suits, he said, cost $14,000 to $20,000.
The association must still get a waiver from the FAA and a permit from the Reno-Tahoe Airport Authority, which owns the airport, before the September races can be held.
Associated Press writers Oskar Garcia, Michelle Rindels and Ken Ritter in Las Vegas contributed to this report.