What happened
Shortly after departing Flint, the flight was instructed by Air Route Traffic Control to hold north of the Saginaw omni range at 3,600 feet. After transitioning to a company frequency, the crew received clearance for an approach into Saginaw (Tri-City) Airport. At approximately 2316, the pilot notified Saginaw radio that the aircraft was positioned over the airport. Weather conditions at the time included light snow showers, a ceiling of 900 feet, and visibility of 3 miles.
Witnesses on the ground observed the aircraft type performing a downwind leg of the traffic pattern. As the plane turned onto the base leg, its landing lights were activated. During this phase, the aircraft was flying below the overcast layer and appeared to be in a descent. While transitioning to the final approach, the aircraft drifted past the runway centerline and performed a steep turn to realign with the extended centerline. Following this maneuver, the plane leveled off briefly before entering a steep descent that resulted in a ground impact. The collision triggered a massive fire, which totally destroyed the aircraft. There were 47 fatalities among the occupants.
Findings
Investigations concluded that the accident was caused by an undetected accumulation of ice on the horizontal stabilizer. This ice buildup, when combined with specific airspeed and the aircraft's configuration, led to a critical loss of pitch control.