NTSB Identification: SEA04LA146.
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Accident occurred Monday, July 26, 2004 in Homedale, ID
Probable Cause Approval Date: 02/24/2005
Aircraft: Schweizer 269C, registration: N62126
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The helicopter was conducting corn pollination operations. The pilot reported that he experienced an engine failure while executing a turn to reverse direction. He further reported that there was a loss of main rotor RPM, and although the pilot attempted to increase rotor RPM by lowering the collective and rolling the throttle "into the overtravel spring," he was unsuccessful in recovering from the low RPM condition. The helicopter landed hard, and the main rotor blades severed the helicopter's tail boom. Initial examination of the engine revealed low compression readings on the cylinders. Partial disassembly of the engine indicated that the low compression was due to loose carbon deposits found on the seating surface of the valves and seats. The carbon was most likely knocked loose during the impact. No other anomalies were noted during the engine examination, and no signatures or conditions were observed consistent with any pre-mishap mechanical malfunction. The reason for the loss of engine power was not determined.

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

The loss of engine power for an undetermined reason while maneuvering at low altitude, which resulted in a hard landing.

Full narrative available

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