NTSB Identification: FTW00LA048.
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Accident occurred Saturday, December 18, 1999 in BROWNSBORO, TX
Probable Cause Approval Date: 12/04/2000
Aircraft: Hughes 269A, registration: N575PF
Injuries: 1 Serious,1 Minor.

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

Prior to the accident, the helicopter was flying on an easterly heading in level flight at approximately 20 knots while making shallow turns following a creek bed. The pilot reported that the helicopter lost all of its lift and power and started descending toward the trees. The pilot added that the anti-torque pedals were ineffective and the helicopter was spinning to the right prior to impact with the trees. Minor repairs were made to the engine in order to run the engine on the helicopter. The engine was started and operated twice within the 1300 to 2500 RPM range for 18 minutes. A representative of the engine manufacturer reported 'no pre-existing engine deficiencies were noted and the investigation did not produce any evidence that the engine was not capable of operating and producing power at the time of the accident.' The conditions at the time of the accident were found to be conducive to the formation of a tail rotor vortex ring state.

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

The loss of tail rotor effectiveness as a result of tail rotor vortex ring state.

Full narrative available

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