Piper PA 30 N7751Y accident near Marion, Indiana

Probable cause

The pilot's exceedance of the airplane's critical angle of attack following a loss of the left engine power shortly after takeoff, which resulted in an aerodynamic stall at an altitude too low for recovery. Contributing to the accident was the loss of left engine power due most likely to a fuel system issue that could not be determined based on the available evidence.

NTSB analysis

The airline transport pilot, who was also an airframe and powerplant mechanic, was conducting a personal flight in a twin-engine airplane after troubleshooting an unknown problem with the left engine fuel system; a family member described the flight as a "test flight." Witnesses reported that, after departure, the airplane climbed to about 500 ft above ground level and began a left turn. During the left turn, the airplane "nose dived" in a downward spiral, and the airplane impacted terrain.

Postaccident examinations revealed no mechanical anomalies with the airframe, right engine, or propellers that would have precluded normal operation. The left engine propeller blade damage was consistent with low or no power at the time of the accident, and the blades were found in an unfeathered position.

Evidence indicated that the pilot had recently replaced the left and right fuel selector valves and had been performing ground engine runs. A comprehensive examination of the airplane's fuel system was not possible due to the extensive fire damage to the system. However, given the unknown left engine fuel system issue, a loose left fuel selector fuel line, and the lack of power signatures on the left propeller blades, it is likely that the fuel system's performance was degraded and led to a partial or total loss of left engine power. The airplane's downward spiral was consistent with the pilot exceeding the airplane's critical angle of attack during a single-engine operation, which resulted in an aerodynamic stall and subsequent loss of control.

Toxicological testing detected a sedating antihistamine in the pilot's liver specimens, but not in his aortic blood specimens, making it less likely that the medication would be impairing. Thus, the pilot's use of this medication was likely not a factor in this accident.

Text from the NTSB. Open the NTSB docket for CEN19FA035 for the full record.