Aug. 27 (Bloomberg) -- An air-race crash last year in Reno, Nevada, that killed 11 and injured 66 resulted from aircraft vibrations that caused a tail-wing part to fail, a U.S. safety board found.
Loose screws in the part that helped the pilot keep the nose pointed downward made the aircraft susceptible to what’s known as flutter, the National Transportation Safety Board found in Washington. The part failure on the modified 1944 P-51D Mustang plane called the Galloping Ghost occurred during a race in which the aircraft reached speeds of 530 miles per hour, the NTSB found.
“One moment spectators were thrilled at the spectacle of speed, only to have it followed by inescapable tragedy,” NTSB Chairman Deborah Hersman said at a meeting today. “The fine line between observing risk and being impacted by consequences when something goes wrong was crossed.”
The NTSB’s findings today and recommendations it issued months ago are an effort to improve safety at future Reno races, starting with the one to be held in two weeks.
While the NTSB has investigated 22 accidents associated with Reno air races in the past 30 years, and positions investigators at events in case of mishaps, this was the first time spectators as well as participants were killed.
This year’s Reno race will be safer as a result of changes the NTSB sought, including a course redesign that moved the race to the north and flattens one of the turns, Hersman told reporters after the meeting.
The Galloping Ghost, running in third place in the third lap of a race on Sept. 16, had been in a steep left turn before it banked sharply to the left, then right, and pitched upward ahead of the crash.
The NTSB couldn’t decide whether the initial steep-left bank was due to the plane being buffeted by the wake of another aircraft ahead of it in the race, or due to the tail-part failure.
The board, after studying hundreds of photograhs of the race from fans and a dozen videos, concluded the tail parts were vibrating a second after the left-bank upset. The G-force generated at that moment, which exceeded 17 times the force of gravity, incapacitated the pilot, who slumped forward in the cockpit next to the control stick he’d just moved to the right in response to the left-bank upset.
The plane at the annual race exhibition was flown by Jimmy Leeward, 74, a movie stunt pilot. Modifications made to the plane by Leeward, who was also its owner, were listed by the safety board as a contributing factor to the accident.
The 10 modifications, nine of which he failed to notify the Federal Aviation Administration about, were designed to make the plane easier to handle at the high speeds he sought in the race. For instance, a right tail-wing part that helped him control the nose of the plane was anchored in place, so he relied only on the similar part on the left tail wing for that control.
The mechanism that let him control that part, called the left trim tab control rod, was the first part to fail as a result of the flutter, the NTSB found.
The pilot was operating the plane at such high speeds that he exceeded the structural limits of the aircraft, originally built in 1944 and rebuilt in 2009. Photographs showed the skin of the plane buckling during the race and the dome over the cockpit being pushed off center.
“He was really testing the limits on this aircraft,” Hersman said.
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