What happened
During the landing rollout, the pilot experienced a loss of control. This caused the PA-46 to veer off the left side of the runway and impact a snow bank. Following this impact, the nose landing gear collapsed.
The investigation
An examination of the nose gear determined that the rear actuator bolt had failed due to an overload during the event sequence. Additionally, the engine mount was found to be bent near the nose gear actuator attach feet.
Investigators later reviewed evidence from a similar accident in Steamboat Springs, Colorado, which revealed structural flexibility in the original engine mount actuator attach feet. This flexibility could result in cracks in the engine mount at the actuator feet. Further investigation into an accident involving a PA-46-310P in Greeley, Colorado, showed bulkhead damage behind the engine mount. A reexamination of the Steamboat Springs aircraft in 2008 also revealed similar firewall damage, with marks indicating the engine mount had been periodically contacting the bulkhead prior to the accident.
Findings
The investigation identified that the original two-piece engine mount design allowed for structural compliance at certain speeds. This resulted in a high shimmying effect and an uncommanded left or right turn of the nosewheel during takeoff or landing. To address these issues, the manufacturer transitioned to a heavy-duty, reinforced one-piece design at the actuator attach point to eliminate relative motion between the feet.