NTSB Identification: WPR12LA428
14 CFR Part 91: General Aviation
Accident occurred Sunday, September 16, 2012 in Ellensburg, WA
Probable Cause Approval Date: 09/12/2013
Aircraft: ROCKWELL INTERNATIONAL 690A, registration: N57112
Injuries: 1 Minor,2 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot reported that, while in a right turn at 7,500 feet mean sea level and above a land wildfire, the airplane entered a turbulent, dark, narrow, column of smoke. The pilot leveled the wings and continued flight through the turbulent column. When the airplane exited the column, the pilot noticed that he had to make a significant right flight control input to maintain level flight. He made a precautionary landing without further incident. Postaccident examination of the airplane revealed that the left aileron control rod was separated along the threaded portion of the shaft, about 2.5 inches from the rod end. Subsequent examination of both pieces of the aileron control rod revealed fracture surfaces consistent with overstress, with no indications of previous wear, fatigue, or corrosion. Thus, it is likely that the turbulence encountered while flying through the smoke column was sufficient to overstress the left aileron control rod.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot’s failure to avoid a turbulent smoke column, which resulted in an overstress failure of the left aileron control rod.

Full narrative available

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