Accident Sequence
According to witnesses, the airplane was seen approaching the motor sports park from the southwest at approximately 1,200 feet agl and at a rate of speed described as faster than usual. The airplane entered a sharp, 90-degree bank as it began to circle the park in a level turn. After circling around to the east, it returned to a wings-level attitude and began to climb. Shortly thereafter, the tail of the airplane began to shake violently and separated from the aircraft. One witness reported hearing a loud noise as the tail came off and the structure began falling apart. The tail section separated first, followed by the airplane pitching over and the left wing breaking off. Witnesses then saw the airplane enter a downward spiral. During the descent, the engine separated and a passenger was ejected. The airplane subsequently entered an inverted flat spin and impacted the ground approximately 1,000 feet north of the park.
Examination
An examination of the airplane's left wing and stabilizers revealed structural failures consistent with overload. The manufacturer's Flight Strength Diagram (Vn diagram) for the G35 indicates that abrupt control column deflection at 113 knots (maneuvering speed) could produce a 4.4 G structural load (limit load factor), while deflection at or above 152 knots (maximum structural cruise speed) could produce a 6.6 G structural load (ultimate load limit).
Engineering Analysis
Review of recorded radar data disclosed that the airplane was traveling at 142 knots at the time of the breakup. Engineering analysis concluded that, in a level turn, the bank angle required to achieve limit load is 76.8 degrees, and the bank angle required to achieve ultimate load is 81.2 degrees. FAA toxicology testing of the pilot revealed the presence of Diphenhydramine in urine, and Norverapamil and Verapamil in urine and liver.