NTSB Identification: CHI98FA353.
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Accident occurred Saturday, September 19, 1998 in CAHOKIA, IL
Probable Cause Approval Date: 03/31/2000
Aircraft: Barklage REVOLUTION MINI 500, registration: N611AB
Injuries: 1 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.

A witness watched the helicopter as it climbed out after takeoff. The witness said that the helicopter was higher than the telephone lines which ran northeast of the airport. 'He was level and climbing, going away from me when all of a sudden, the sound (engine sound) went quiet, followed by a pop. It was not a loud pop.' The helicopter began a shallow descent. At about 30 to 40 feet above the field, the helicopter 'leveled out,' but 'kept coming down.' The witness said he saw the helicopter 'hit' and then 'cartwheel.' Examination of the helicopter's engine revealed scoring marks on the power-takeoff cylinder (front cylinder) piston, and impact marks in the head. Small metallic particles were embedded in the piston head. The power-takeoff cylinder wall showed scuff marks, and the cylinder head showed impact marks. The two power-takeoff spark plugs' showed no gap at the electrodes, and impact marks. No other anomalies were revealed.

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

A loss of engine power due to cold seizure of the power-takeoff cylinder. A factor contributing to the accident was the power lines.

Full narrative available

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