What happened
Prior to the accident, the pilot intended to fly the aircraft to undergo its scheduled annual inspection. An individual assisting with pre-flight preparations observed the departure and reported no visible abnormalities during the initial takeoff and climbout. However, a witness near the crash site observed the aircraft flying at a very low altitude, approximately 200 feet above a residence, while descending toward a treeline. This witness noted that the right engine was not operational and the right propeller was stationary, while the left engine appeared to be running at high power. During the descent, the aircraft pitched upward to avoid a power line before rolling to the right and striking the trees, which was followed by an explosion and smoke.
Findings
Investigation of the wreckage showed that the right propeller assembly sustained heavy frontal impact. The propeller blades were bent but lacked rotational scoring, suggesting they were not spinning at the moment of impact. The blades were positioned at roughly 23 degrees, rather than the 86-degree angle characteristic of a feathered propeller. While the right engine's power loss could not be definitively identified due to fire and impact damage, the left engine and airframe showed no signs of mechanical failure.
Maintenance records indicated that the aircraft's annual inspection was 12 days past due. Additionally, the right engine had exceeded the recommended 1,200-hour interval for overhaul, having reached 1,435 hours since its last major overhaul, and neither engine had been overhauled within the last 12 years. It is believed that the pilot failed to feather the propeller before the engine RPM dropped below the critical 1,000 RPM threshold, preventing the blades from engaging in the proper feathered position.