A lethal combination of worn aircraft parts and unprecedented speed caused last year 's Reno Air Races crash , which killed a veteran pilot and 10 spectators , and injured more than 60 others , federal accident investigators concluded Monday . The main culprits , according to the National Transportation Safety Board , were several lock nuts on the left trim tab -- an aerodynamic surface on the horizontal part of the plane 's tail -- nuts that had not been replaced in at least 26 years . The worn nuts allowed screws to loosen -- possibly years ago , without apparent consequence , the NTSB said . But when pilot Jimmy Leeward pushed the highly modified P-51 Mustang to a speed of 445 knots -- 35 knots faster than it had ever flown before on the Nevada race course -- the flaw caused flutter vibrations in the plane 's trim tabs . The plane pitched up at about 17 Gs of acceleration , incapacitating Leeward . Reno air race organizers hope to continue race after deadly crash . The plane rolled , plunged towards the ground and slammed into a box seating area , showering the area with debris . When the incident happened last September , it threatened to bring an end to the National Championship Air Races in Reno , the only race of its kind in the nation . But organizers have compiled a complete schedule of races from September 12 through 16 , saying they have made numerous safety improvements recommended by the NTSB . Among the improvements : race planes will be required to demonstrate their airworthiness at racing speeds before participating in races , spectators will be seated further from the aerial race course and the Reno Air Races has `` flattened '' the tight turn where last year 's accident occurred . `` Pilots know that they are taking risks , but air race pilots expect that the risks taken are theirs alone , '' said NTSB Chairman Deborah A.P . Hersman . `` The spectators assumed that their safety had been assessed and addressed . '' Hersman said the NTSB made its recommendations in April to give the Reno Air Racing Association time to implement the changes for this year 's race . The NTSB said major modifications to the aircraft , intended to make the plane faster , contributed to the accident . Its 37-foot wingspan had been reduced to 29 feet . Some of the changes were undocumented and had a detrimental effect on the World War II-era aircraft , which was known as `` The Galloping Ghost . '' For instance , investigators said , the plane 's right trim tab -- a piece of the tail -- was locked in position aligned with the tail . Pilot overwhelmed by g-forces in Reno crash . `` On this airplane , you should have both trim tabs , '' investigators said . `` This pilot put a screw through there to fix it in position , and when you do that , he lost redundancy . You have put all the eggs in the basket of hoping the left elevator will not fail . And it did fail . '' Leeward 's age , 74 , was not found to be a factor in the crash . The 17 g forces that resulted from the failure greatly exceeded human tolerances , the NTSB said . It is difficult for trained pilots to remain conscious with even 5 Gs , the NTSB has said . The accident investigation was greatly aided by numerous movies and photographs by spectators , according to the NTSB . Since the accident , several victims and family members have filed suit , one alleging that the crash was not a `` freak accident , '' but was `` the predictable result of a reckless drive for speed by a risk taking pilot and crew , coupled with an insatiable drive for profit '' by race organizers . The Reno racing association , meanwhile , announced last week it has set up a $ 77 million fund to compensate victims or heirs . The program is being administered by Kenneth Feinberg who administered funds for victims of the 9/11 terrorist attacks and the BP Deepwater Horizon disaster . The Reno crash focused attention on the dangers of air races and air shows . In addition to the 11 people killed at the Reno races , five performers died at air shows elsewhere last year . Federal regulators and air show organizers vouch for the safety of the system , saying rules for U.S. air shows are stricter than those in other countries . NTSB focuses on deadly year in air races , shows .
A veteran pilot and 10 spectators died in last year 's Reno Air Races crash . The NTSB finds that flying parts and speed caused the crash . ` ` Air race pilots expect that the risks taken are theirs alone , '' the report says . ` ` The spectators felt that their concerns had been assessed and addressed ''