A tail-wing part of a stunt plane’s flight controls failed just before it crashed into a crowd watching a September 2011 air show, the National Transportation Safety Board said in releasing evidence from its investigation.
Loosening screws, including one with a crack, may have led to vibrations known as flutter that caused the failure in the modified P-51D Mustang plane called the Galloping Ghost during a race in Reno, Nevada, according to a report by the safety board’s aircraft-performance study group released today. The crash killed 11 people and seriously injured 66.
The flutter also may have developed from the wake of another aircraft in the Reno Air Races. There is no indication the failure resulted from the way the pilot handled the plane, the study group found.
“During the race the speed and vertical loading of the Galloping Ghost was comparable to other racing P-51s,” the NTSB group said. “There was no indication that an increase in static aerodynamic forces overloaded to cause the failure.”
The NTSB report raises the possibility that the failure of the part called the left trim tab control rod may have contributed to the crash. The study group couldn’t determine from photographic evidence whether the failure occurred before the plane began to lose control or about a half-second afterward.
The NTSB will analyze the evidence it released today and determine the probable cause of the accident later this month, the board, which investigates aviation accidents, said in a statement.
The plane at the annual race exhibition was flown by Jimmy Leeward, a veteran movie stunt pilot. The plane was flying in the final event of the day on Sept. 16, 2011, when it crashed into the box-seat area near the center of the grandstand.
The plane had been in a steep left turn before it banked left, then right and pitched upward ahead of the crash. The motion of the aircraft as it rolled at the start of the accident sequence was consistent with failure of the left trim tab and its effect on the pilot, the NTSB study group found.