What happened
On the night of the accident, Air South Flight 168 departed from Atlanta at 21:07. Shortly after takeoff, at 21:13, the crew reported that the Beechcraft aircraft had reached its assigned cruising altitude of 7,000 feet. The flight continued at this level for approximately eleven minutes.
During the cruise phase, the aircraft experienced a gradual change in pitch due to an unexpected shift in the longitudinal trim. The pilots identified the nose-down attitude roughly six seconds after the movement began and attempted to implement recovery procedures. However, the horizontal stabilizer continued to migrate into a full nose-down position.
This shift created a high-speed dive that required extreme physical force on the control column to counteract. Despite the efforts of the crew, the aerodynamic forces required to maintain control exceeded what could be achieved by the pilots. The aircraft descended rapidly until it reached a near vertical attitude, at which point both wings suffered structural failure due to high-speed stresses just before the impact with the ground.
Findings
Investigations concluded that an unintended change in the longitudinal trim caused a nosedown condition that was physically impossible for the crew to overcome. While the specific trigger for the initial trim movement could not be identified, it was noted that the design of the flight control system was susceptible to malfunctions. If such a malfunction occurs without immediate detection by the crew, it can lead to an uncontrollable flight state.