NTSB Identification: CHI08CA252.
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Accident occurred Friday, August 15, 2008 in Cokato, MN
Probable Cause Approval Date: 09/26/2008
Aircraft: Hiller UH-12E, registration: N945HA
Injuries: 1 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The pilot reported he made three passes over the fields that he was going to spray. He stated he noticed a power line pole that had a transformer cover on it and what appeared to be a wire covering running up the pole. This led the pilot to believe that the power lines in the area were buried. The pilot then landed and loaded the chemicals. He stated that after taking off with the load, he flew one more pass to look for power lines and still did not see any. He stated that during the first swath run, the helicopter contacted power lines. The helicopter initially pitched nose up and to the right. The pilot stated he pushed the nose down and to the left, but the power lines wrapped around the control tubes and tail rotor. The helicopter then entered a descending spin. The pilot stated he pulled back to flatten the descent just prior to the helicopter contacting the ground.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot did not visually identify and maintain clearance with the power lines, and the pilot's inability to maintain control of the helicopter once it contacted the power lines. Factors associated with the accident were the low altitude operations being conducted and the power lines.

Full narrative available

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