What happened
During a mission intended to deploy eight parachutists from 13,000 feet, the aircraft experienced a catastrophic loss of control. As the flight approached the airport, the pilot requested a higher drop altitude due to cloud cover. During the approach, the aircraft's airspeed began to decrease. Approximately one kilometer from the designated jump point, the aircraft abruptly veered left and entered a steep descent.
For a distance of nearly one kilometer, the aircraft descended 1,500 meters at a dive angle exceeding 45 degrees. During this maneuver, the structural integrity of the aircraft type was compromised as airspeed and g-forces surpassed safe operating limits, causing the plane to break apart in mid-air. From an altitude of 2,000 meters, the wreckage fell vertically at a rate of approximately 60 m/s. All passengers and crew, totaling 8 fatalities, remained inside the aircraft and died upon impact. The extreme g-forces and rotations likely prevented any occupants from deploying their parachutes.
Findings
Investigation into the circumstances revealed that the pilot lacked critical weight and balance data prior to departure. The provided load sheet omitted the total mass of the load and the individual weights of the eight parachutists. Consequently, the pilot was unable to perform necessary mass and balance calculations to ensure the aircraft was within safe operating parameters for the flight.