Piper Aircraft Inc PA 46-350P N451MA accident near Hartsburg, Missouri

Probable cause

The pilot’s encounter with convective weather conditions, which resulted in a loss of airplane control, the exceedance of the airplane’s never exceed speed, and the resulting overload failure of the horizontal stabilizer and subsequent failure of the airplane’s wings.

NTSB analysis

The airplane was on an instrument flight rules flight and air traffic control (ATC) provided the pilot with vector guidance to avoid an active military operations area (MOA). The controller informed the pilot that he would only be able to deviate to the left of his course due to the active MOA. At that time, the airplane was in an area of developing convective weather activity and likely in instrument meteorological conditions. The pilot reported to ATC that he encountered freezing rain. ATC communications revealed that the pilot requested to deviate to the left of his course due to weather, including mention of encountering freezing rain, which ATC approved. Flight track data showed the airplane entered a descending left turn. A performance study based on the aircraft track data showed that, during the turn, the airplane’s roll angle reached 70°, the pitch angle reached -17° and then -34°, and the calibrated airspeed exceeded both the airplane's published never exceed speed (VNE), and its maximum operating maneuvering speed (VO). During the turn, the airplane’s structure broke apart, and wreckage was distributed along a 3-mile path. The flight path depicted in the flight track data was consistent with a loss of airplane control.

Postaccident examination of the airplane confirmed that the horizontal stabilizer and the wings failed in a downward direction. A failure of the airplane’s horizontal stabilizer would result in the airplane pitching forward and a high negative load to the wings. The examination noted that all identified failures in the airplane structure had signatures consistent with overload failure. Examination of the airplane’s flight control system did not reveal any preexisting anomalies. The cockpit avionics could not be tested due to impact damage.

Based on the available data, the pilot encountered forecast adverse weather associated with convective activity. The pilot noted to ATC that he encountered freezing rain, however, the quantity of ice accumulation and its effect on the flight could not be determined. While attempting to deviate from his flight path to avoid this weather, airplane control was lost and it entered a steep descending turn. During the turn, the airplane’s speed exceeded its published never exceed speed, which resulted in overload failure of the horizontal stabilizer and subsequent failure of the airplane’s wings.

Text from the NTSB. Open the NTSB docket for CEN24FA160 for the full record.