What happened
A cargo operation departing from Arica for Puerto Suarez experienced a critical mechanical failure while traversing the Andes Mountains. During the flight, the aircraft's right engine suffered a loss of power. Because the plane was carrying an excess load of approximately 1,000 pounds, the crew could not sustain sufficient altitude following the engine malfunction.
In an attempt to perform an emergency landing, the pilot maneuvered the aircraft toward a landing site, but the plane struck stone walls near Belén. The impact resulted in a post-crash fire that consumed the airframe. There were five fatalities among the occupants of the aircraft.
Findings
Investigations into the incident focused on the loss of power in the right engine. While investigators could not definitively establish the primary reason for the initial failure, they determined that an exhaust valve in the number 10 cylinder had failed. This failure caused the piston to strike the spark plugs and the cylinder head, leading to the subsequent engine malfunction.