NTSB Identification: LAX04LA216
14 CFR Part 91: General Aviation
Accident occurred Thursday, May 20, 2004 in Palmdale, CA
Probable Cause Approval Date: 01/31/2006
Aircraft: Bell 206L-3, registration: N2019F
Injuries: 2 Minor,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 was performing an aerial filming operation when he heard a bang, perceived a loss of engine power, and made an autorotative landing, which resulted in a rollover. The helicopter was heading in a southerly direction, at 200 feet above ground level (agl) and at 80 knots, in a left-hand turn, when the pilot heard a bang and felt a loss of engine power. He entered an autorotation and maneuvered the helicopter towards an open field. He checked for engine power by pulling up on the collective as he descended and did not feel any power, however, he did not check his engine instruments to verify the loss of engine power. The pilot flared the helicopter and landed hard, then it rolled over on its right side. Examination of the wreckage found evidence of driving torsional deformation in the forward short shaft (engine oil cooler/tail rotor drive shaft). The flight control push-pull tubes and bell cranks were traced and continuity was established. The helicopter's fuel boost pump was energized and 27 gallons of fuel was successfully pumped up to the airframe fuel filter and deposited in to a 50-gallon fuel drum. Main transmission gearbox and tail rotor gearbox magnetic chip detectors were removed and examined for debris. None were found and both transmissions operated smoothly. The engine was removed from the helicopter and installed in an instrumented test cell. Once started, the engine successfully produced 459 ft-lb of torque. It was then set at flight idle and jam accelerated to max power. No surging or popping of the engine was noticed during the jam acceleration, and the turbine speeds and engine temperatures quickly stabilized. This test was performed two times with similar results. The engine operated in the test cell continuously for 1 hour 15 minutes.

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

The momentary loss of engine power for undetermined reasons.

Full narrative available

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