NTSB Identification: DEN99LA168.
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Accident occurred Thursday, September 23, 1999 in TREMONTON, UT
Probable Cause Approval Date: 06/23/2000
Aircraft: Bell 47G3B2A, registration: N83246
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 pilot departed the airport en route to a local staging area to perform aerial application work. He departed with 30 gal. of fuel and was planning to pick up a load of chemical spray at his destination. Approximately 2 1/2 miles southeast of the airport, the engine began to miss. He decided to make a precautionary landing in an alfalfa field. When the helicopter was 200 ft. agl, the engine began to run rougher and he initiated an autorotation. He closed the throttle and the engine quit. The helicopter impacted the ground, stopped suddenly and rocked forward. The rotor blades flexed downward, severing the tail boom. The day following the accident, an examination of the engine was performed by an FAA maintenance inspector and no discrepancies were found. When asked what recommendation the pilot could make as to how the accident could have been prevented, he responded that he could have 'performed [a] better autorotation.'

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

The pilot's failure to maintain rotor rpm while attempting a precautionary autorotation landing. A factor was the loss of engine power for undetermined reasons.

Full narrative available

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