What happened
During the cruise phase of flight at a steady altitude of 4,000 feet, radar data indicated that the aircraft's speed decreased from 180 knots to 120 knots over a two-minute interval. The stability of the altitude during this deceleration suggested the use of autopilot and autotrim functions, which was consistent with the presence of turbulence and icing conditions. During this period, the co-pilot issued a mayday call reporting an uncontrolled spin.
Investigation into the aircraft's configuration revealed that the elevator trim was set to approximately 13 degrees nose up. While no mechanical failures were identified in the engines, airframe, or onboard systems prior to impact, evidence indicated that the crew may have become inattentive following a reduction in power while the autopilot was engaged. When power was subsequently applied, the aircraft pitched upward from its low airspeed, leading into an unrecoverable state.
Findings
- The accident resulted in five fatalities.
- The investigation identified several contributing factors involving the pilot in command, including improper management of throttle and trim settings.
- Environmental factors included the presence of icing and turbulence.
- Crew inattention following power reduction was a primary factor in the loss of control.
- The pilot's duty day was nearing 11 hours at the time of the incident, suggesting fatigue played a role in the handling errors.