What happened
The flight was operating under instrument flight rules with the intention of picking up cargo at its destination. During the descent, approximately 14 minutes before the impact, the aircraft type encountered a layer of moderate rime ice. The flight crew acknowledged the presence of airframe icing during the descent. After reaching visual flight rules conditions, the crew canceled their IFR clearance and proceeded with a right-hand circling approach.
As the aircraft transitioned into the base leg of the traffic pattern, the pilot flying requested full flaps, and the engine power was adjusted multiple times. During this period, the pilot inquired about the autopilot and the fuel balance. The monitoring pilot noted a potential issue with the spoilerons. Shortly after this exchange, the first officer commanded full engine power, but the aircraft subsequently struck the terrain. There were zero survivors of the impact.
Findings
Investigation of the cockpit voice recorder indicated that the crew engaged in non-sterile cockpit discussions below 10,000 feet, including a lengthy conversation regarding Class B airspeeds. This contributed to a relaxed atmosphere and informal checklist execution. In the final 24 seconds of the flight, both pilots appeared focused on investigating handling difficulties related to the aircraft's roll characteristics and fuel balance. It is believed that the crew failed to recognize the decaying energy state of the aircraft before it became critical.
While the cockpit lights for the aileron augmentation system and stall warnings had illuminated, no mechanical failures or anomalies were found in the aileron augmentation system or other aircraft components. The exact impact of the rime ice on the aircraft's performance could not be definitively determined.