NTSB Identification: BFO90LA065.
The docket is stored on NTSB microfiche number 43614.
Accident occurred Friday, July 27, 1990 in PADUCAH, KY
Probable Cause Approval Date: 11/23/1992
Aircraft: ROBINSON R22, registration: N9017S
Injuries: 2 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 IMPACTED TO THE GROUND AFTER A LOSS OF TAIL ROTOR THRUST DURING AN ATTEMPTED TAKEOFF. INVESTIGATION REVEALED THE INTERMEDIATE FLEX PLATE AND TWO CLUTCH YOKES AND FAILED. A METALLURGICAL EXAMINATION REVEALED THAT THE WASHERS IN ONE OF THE FASTENER JOINTS WERE MISPLACED. A WARNING IN THE MANUFACTURER'S MANUAL STATES: 'A559 NICKEL-PLATED RADIUSED WASHERS ARE REQUIRED ON EACH SIDE OF THE A193 FLEXPLATES OR FRETTING FAILURE MAY OCCUR WITHIN A FEW HOURS.' RECORDS INDICATE THE MOST RECENT ANNUAL INSPECTION WAS SIGNED OFF ON OCTOBER 19, 1989, AND THE AIRCRAFT HAD ACCUMULATED 119 HOURS SINCE THAT TIME. THE HELICOPTER HAD UNDERGONE A PRE-PURCHASE INSPECTION ABOUT ONE MONTH PRIOR TO THE ACCIDENT.

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

THE LOSS OF TAIL ROTOR THRUST DUE TO IMPROPER PART INSTALLATION.

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