Piper PA-23-250 N62793 accident near Sterling, Kansas

Probable cause

The loss of pitch control during cruise flight resulting from the separation of the stabilator trim actuator due to inadequate maintenenace.

NTSB analysis

The airplane was in cruise flight at 6,000 feet mean sea level when it entered an uncontrolled descent and impacted terrain in a right wing low attitude. The airplane cartwheeled, impacted a cow, and scattered components and debris over a distance of 668 feet. Examination of both stabilators revealed extensive aft streaking, initiating along the forward rivet line, consistent with working or "smoking" rivets. Examination of the stabilator trim tab fittings exhibited little deformation and the inboard rivet faces had been knocked off. The stabilator trim pushrod was not attached. The securing nut and cotter pin, used to secure the pushrod to the tab was missing. The lack of deformation to the trim pushrod is indicative that the securing nut backed out during flight. The stabilator trim bellcrank, left side, was loose within its attach point and exhibited significant freeplay. Disassembly revealed elongation of the attach hole. These observations indicate prolonged inadequate maintenance. A review of the pilot's training, experience, and qualifications revealed no issues.

Text from the NTSB. Open the NTSB docket for DEN08FA058 for the full record.