The NTSB says (PDF) it's likely a five-year-old girl's restlessness started the chain of events that led to the crash of a helicopter that killed her and four others on Valentine's Day in 2010. Although there is no direct evidence to support the hypothesis, the board says simulator scenarios and a biomechanical study point to the girl, who was sitting on her father's lap in the left pilot seat of the Eurocopter EC135, inadvertently stepping on the collective control and pushing it suddenly to its bottom stop. Then, the board postulates, either the pilot in command in the right seat or the left-seat passenger (and aircraft owner) yanked up on the collective and back on the cyclic. The violent control movements then caused the main rotor to hit the tail boom, causing the aircraft to go out of control about 2,000 feet above the Arizona desert near Cave Creek. The board cited the pilot's failure to enforce "proper cockpit discipline" as a contributing factor in the crash.
The NTSB said aircraft owner Thomas J. Stewart, the owner of Services Group America, had previously allowed his daughter Sydney to travel on his lap in the left pilot seat. Father and daughter, along with Stewart's wife Madena and her brother Malang Abudula, were traveling from their northern Arizona ranch to Scottsdale. The pilot was Rick Morton. The pilot's family is suing Eurocopter, claiming a faulty repair to a rotor blade caused the accident, their lawyer told The Associated Press. The NTSB said in the report that its investigation showed a rotor blade hit the tailrotor drive shaft and broke. "That's their interpretation, and it does not comport with what our experienced investigators believe happened," said Gary C. Robb, a Kansas City attorney.