Incident Overview
An external load operation was being conducted to move seismographic oil exploration equipment. The helicopter was equipped with a 150-foot cable and an aluminum bucket. After arriving at the loading zone, the pilot lowered the bucket and hovered while it was loaded. Once the bucket was filled, the pilot lifted it to approximately 40 feet above ground level (AGL).
Problem and Descent
At around that altitude, the pilot transmitted that he had a problem and needed to set the helicopter down. The loaded bucket then came down hard about 10 feet from its pickup point. The helicopter subsequently moved to a clear area.
Tree Strike and Crash
Following the hard bucket landing, the helicopter struck the top of a tree and then crashed into the ground approximately 90 feet from the tree. The aluminum bucket had been dragged about 200 feet before coming to rest at the bottom of the tree. The cable was draped across the tree and the right skid but was found released.
Examination Results
An examination of the helicopter revealed no precrash malfunction of the flight controls, and no mechanical failure of the engine was verified.