NTSB Identification: SEA99LA092.
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Accident occurred Tuesday, June 22, 1999 in SHELTON, WA
Probable Cause Approval Date: 08/03/2000
Aircraft: Hughes 369D, registration: N1089Y
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 was practicing autorotations from an altitude of approximately 200 feet above ground level (AGL) and an airspeed of approximately 50 knots. During the second practice autorotation, the pilot reduced power with throttle and used collective to adjust rotor speed to 410 RPM (minimum RPM for practice autorotations). The rotor RPM decreased below 410 RPM and the aircraft rapidly started to descend. Before the pilot was able to recover, the aircraft collided with the ground and rolled over. The aircraft sustained substantial damage to the main rotor blades, tail rotor, tail boom and fuselage. The pilot reported no mechanical failures or malfunctions with the aircraft at the time of the accident.

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

The pilot's failure to maintain rotor RPM during an autorotation.

Full narrative available

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