NTSB Factual Report

HISTORY OF FLIGHT

On July 10, 2009, about 1427 central daylight time, a Zivko Aeronautics Edge 540, N26HB, piloted by a commercial pilot, was destroyed when it impacted the ground near the Gould Peterson Municipal Airport (K57), Tarkio, Missouri. The flight was a practice flight by an aerobatic performer who was scheduled to perform at an airshow the following day. The airplane impacted the ground during recovery from one of the aerobatic maneuvers. The 14 CFR Part 91 flight was operated in visual meteorological conditions and was not on a flight plan. The pilot was fatally injured. The local flight originated from K57 at an undetermined time.

A witness provided a video of the accident flight. The video showed the airplane in a climbing vertical roll which was followed by what appeared to be an inverted spin. The rotation of the spin was halted with the airplane in a near vertical descent. During the recovery from the dive, the airplane suddenly rolled to the right and rotated about 1-1/2 turns before impacting the ground in a nose low, right wing down attitude. Audible engine sounds were present throughout the recording.

PERSONNEL INFORMATION

The pilot, age 36, held a commercial pilot certificate with airplane single engine land, airplane multiengine land, and instrument airplane ratings. The certificate also listed type ratings for DC-3 and Lear Jet airplanes. She was an international aerobatic performer and a three-time member of the United States Unlimited Aerobatic Team.

The pilot held a second class medical certificate issued on May 27, 2009. No limitations were listed on that medical certificate. On the application for that medical certificate the pilot reported a total of 1700 hours of flight time.

AIRCRAFT INFORMATION

The airplane was a Zivko Aeronautics Edge 540, serial number 0022, single seat aerobatic monoplane. The Edge 540 was designed for full competition unlimited aerobatics. The airplane had an all composite wing and steel tube fuselage structure. A modified Lycoming AEIO-540-EXP engine, serial number L-50324-98, turning a Hartzell HC-C3YR-4AX composite, three blade, constant speed propeller powered the airplane. According to manufacturer information, the airplane had a maximum gross weight of 1,800 pounds, an aerobatic gross weight of 1,550 pounds and the airframe was capable of withstanding -12 to +12 g loading.

METEOROLOGICAL INFORMATION

The weather at the Shenandoah Municipal Airport (SDA), Shenandoah, Iowa, about 18 nautical miles north of the accident site, at 1415, was: Winds 110 at 14 knots gusting to 20 knots; visibility 10 statute miles; scattered clouds at 3,500 feet above ground level (agl); temperature 26 degrees Celsius; 23 degrees Celsius; altimeter setting 29.96 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

Examinations of the airplane were conducted following the accident by representatives of the Federal Aviation Administration (FAA), and the aircraft manufacturer.

The airplane’s fuselage was crushed and fragmented from the nose aft to the cockpit section. The aft fuselage remained partially intact with fractures and bending of various structural members. The vertical stabilizer and rudder were intact and remained attached to the aft fuselage. The left horizontal stabilizer and elevator remained attached to the aft fuselage. The right horizontal stabilizer was separated from the airplane. The right wing was fragmented. The left wing was separated from the fuselage and was fractured about mid span into two main pieces. The wing spar attachment to the fuselage was intact.

The airplane’s elevator control system components remained unbroken from the control stick to the elevator surface with the exception of the push-pull tube from the control stick to the forward idler bell-crank. The fractured portion of the push-pull tube exhibited bending, and flattening of the tube at the break consistent with impact damage. Other components in the elevator control system had varying amounts of deformation but remained intact.

Both rudder pedals remained unbroken and were still attached to fuselage structure. The right rudder cable was intact. The left rudder cable was separated in the area of the cockpit. The broken ends of the cable exhibited features consistent with overload failure.

The airplane’s aileron control system exhibited multiple breaks in push-pull tubes. All of the tubing breaks exhibited bending and flattening of the tubes at the breaks consistent with impact damage. One of the machined end fittings of the push-pull tube that connected the torque tube to the center aileron bell-crank had separated from the tube. The fitting was fastened to the tube with four rivets spaced 90-degrees apart around the circumference of the tube. The rivet holes in the end fitting exhibited axial elongation toward the end that was inserted into the tube. The rivet holes in the tube exhibited axial tearing toward the end of the tube. The rivets were not found. The damage to the end fitting and tube was consistent with rivets having been in place prior to the separation.

No pre-impact deficiencies with respect to the airplane’s control system were found.

No examination of the airplane’s engine was conducted.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy of the pilot listed the cause of death as massive blunt trauma.

A Final Forensic Toxicology Fatal Accident Report prepared by the FAA, listed the following findings:

>> 0.068 (ug/ml, ug/g) Phentermine detected in Blood

>> Phentermine detected in Gastric

>> Phentermine detected in Heart

>> Phentermine detected in Lung

A review of the pilot’s personal medical records indicated multiple prescriptions for phentermine, for weight loss, in 2006 and 2007, including prescriptions filled on May 5, 2006, May 12, 2006, and June 21, 2006, but no prescriptions for phentermine filled at the pilot’s pharmacy since September 5, 2007. Phentermine was not noted on sequential applications for 2nd class FAA airman medical certificates completed by the pilot on June 15, 2006, March 6, 2008, and May 27, 2009.

NTSB Probable Cause

The pilot's failure to maintain aircraft control during the aerobatic flight.