Incident
A cargo flight operating a route from Rio Grande to Buenos Aires via Río Gallegos and Río Cuarto encountered delays during the loading of 99 sheep. The departure from Río Gallegos occurred after dark, and the planned destination had been changed to Villa Reynolds, which had electric runway lighting, instead of Río Cuarto, which used kerosene lamps (putts).
Sequence of Events
As weather conditions deteriorated, the crew did not switch to an instrument flight rules (IFR) flight plan. Attempts to contact Villa Reynolds were unsuccessful, prompting the crew to divert to Río Cuarto. They navigated by following a roadway, which was intermittently illuminated by lightning flashes and automobile headlights.
Upon reaching the vicinity of Río Cuarto, the crew overflew the airport. Airport personnel were unable to keep the kerosene lamps lit due to rain and wind. Four vehicles were dispatched to mark the runway threshold with their headlights. The crew became disoriented and requested the controller to determine the aircraft's position relative to the airport by listening to engine noise.
During a second pass over the field in an attempt to locate the runway, the aircraft descended and struck the ground. It slid for approximately 300 meters, broke through a wire fence, and came to rest in a cornfield about 5 kilometers northeast of the airport. All four occupants were rescued, but the aircraft sustained damage beyond repair.
Probable Cause
The official probable cause was stated as: "Collision with terrain while trying to land in adverse and unstable conditions due to continuation of the flight at night in known and visible adverse meteorological conditions, aggravated by the lack of an alternate aerodrome or sufficient endurance to effect a diversion."