NTSB Identification: CHI05FA274.
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Accident occurred Saturday, September 24, 2005 in Drummond, WI
Probable Cause Approval Date: 09/27/2007
Aircraft: Robinson R44, registration: N9158U
Injuries: 3 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

The helicopter was being operated for hire providing rides during a festival when it struck a power line over a lake. Visual meteorological conditions prevailed at the time of the accident. A witness stated that he heard the helicopter for approximately one minute and during that time he heard a pitch change, heard the revolutions per minute increase, and then heard the crash. The power line was at a height approximately equal to the height of the trees surrounding the lake. According to the operator, no safety briefings were given to ride passengers and the helicopter was not shut down when passengers were loaded and unloaded. A previous ride passenger stated that when he arrived on the morning of the accident, there was no safe area delineated around the helicopter and no safety briefing given. This witness stated that the engine was running when the pilot got out of the helicopter in order to secure the passenger's seatbelts. There had been a written complaint regarding the operator when a witness saw the helicopter being operated in a "manner contrary to all safety guidelines outlined in the manufacturer's Safety Course and Special Federal Aviation Regulation 73.1." The owner of the company stated that after that they no longer provided a "wild" ride. Examination of the helicopter's flight control and propulsion system revealed no anomalies that would have precluded normal operation. Examination of the helicopter’s seat belt buckles revealed fatigue fracture within the buckle, which was later addressed in a Special Airworthiness Information Bulletin and the helicopter manufacturer's service bulletin.

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

Clearance not obtained/maintained by the pilot during an unknown phase of flight. Contributing factors were the improper use of procedures by the pilot, the inadequate surveillance of the operation by company/management, and the wire.

Full narrative available

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