What happened
At 20:30, the pilot reported descending from 6,000 feet and confirmed having the airport in sight. After being cleared for the approach by the controller, the pilot requested to cancel his IFR clearance and switch to the traffic advisory frequency. The controller granted this request, but no further transmissions were recorded from the flight.
Radar data indicated the aircraft was southeast of the airport, maintaining a westerly heading south of the airport. At 20:35, the aircraft crossed a river and began a sharp left turn away from the airport. The aircraft completed approximately 90 degrees of this turn before abruptly disappearing from radar contact. The final radar target was located on the west side of the river near the impact site.
Following several weeks underwater, highly fragmented wreckage was recovered from the river.
The investigation
An examination of the engines during the teardown process revealed that the left engine was not rotating or operating at the time of impact, and the left propeller was in the feathered position. In contrast, the type and degree of damage to the right engine indicated it was rotating and operating at the moment of impact. Investigators found no pre-existing conditions regarding the airframe systems or either engine that would have interfered with normal operation or explained why the left engine had shut down.