What happened
During a nighttime departure from Tomonoco Airport, a Convair CV-440 experienced significant issues maintaining altitude. Shortly after takeoff, the aircraft failed to achieve the necessary height required for the terrain and collided with the slope of Mt Colorado, situated a short distance from the airfield.
The impact caused the airframe to break apart. There were 67 fatalities in the accident, with no survivors reported among the passengers or crew. The flight was carrying several Army officers and their family members who were traveling toward La Paz when the disaster occurred.
Findings
Investigations into the crash revealed that the aircraft was operating beyond its certified weight limits. While the Convair CV-440 had undergone modifications by the military to increase passenger capacity, these changes resulted in an overloaded state during this specific flight.
Because of the heavy load, the plane could not maintain the steep climb gradient necessitated by the mountainous environment surrounding Tomonoco Airport. This inability to gain sufficient altitude led directly to the collision with the mountain slope.