The airline transport pilot was conducting a personal flight in the experimental amateur-built Van’s RV-7, with one passenger on board.
Several witnesses near Hurricane, Utah, reported that they heard the airplane’s engine and that it sounded like it was making power changes. They then saw airplane debris floating in the air.
One witness stated that the engine was running during the entire descent and that he saw the airplane spiraling and descending in a cork-screw type maneuver.
Another witness reported seeing the airplane inverted at a low altitude just before impact. Both souls aboard died in the crash.
Post-accident examination revealed damage to the horizontal stabilizers and elevators that was consistent with a downward failure in positive overload.
The loads required to fail the horizontal stabilizers and elevators cannot be generated from normal flight or control movements. Such failures would have required an abrupt pull back on the stick and corresponding movement of the elevator to a trailing-edge-up position, at speeds greater than the airplane’s maneuvering speed.
Failure of the horizontal tail first would have caused the airplane to pitch down rapidly, producing air loads on the upper surface of the wing that were sufficient to fail them in negative overload.
The damage observed on the wings was consistent with a downward failure in negative overload.
Additionally, there were no indications of any pre-existing cracks or anomalies with the horizontal stabilizers, elevators, or wing structures, and no pre-accident anomalies were observed that would have precluded normal control of the airplane.
A review of the weather information indicated that there were likely low-level winds gusting from 26 to 46 knots at the time of the accident and that moderate-to-severe turbulence likely existed at the accident site.
The weather conditions likely contributed to the in-flight breakup by either aggravating a flight maneuver or preventing a recovery from a loss of airplane control.
Probable cause: The pilot’s abrupt flight control inputs, likely above the maneuvering speed, in severe winds and turbulence conditions, which resulted in an in-flight breakup.
NTSB Identification: WPR16FA036
This December 2015 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.