NTSB Identification: LAX93LA058.
The docket is stored on NTSB microfiche number 50036.
Accident occurred Wednesday, December 02, 1992 in FRESNO, CA
Probable Cause Approval Date: 09/14/1993
Aircraft: ROBINSON R-22 BETA, registration: N80142
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 HELICOPTER TAIL ROTOR GEAR BOX AND THE VERTICAL FIN SEPARATED DURING CRUISE FLIGHT. THE PILOT WAS ABLE TO LAND THE HELICOPTER IN A FLOOD BASIN. THE WRECKAGE EXAMINATION DISCLOSED THAT THE FUEL CAP CAME OFF THE FUEL TANK AND STRUCK A TAIL ROTOR BLADE. THE TAIL ROTOR BLADE BALANCE WEIGHT SEPARATED AS DID THE ENTIRE VERTICAL FIN. THE TAIL ROTOR ASSEMBLY REMAINED ATTACHED TO THE HELICOPTER BY ITS PITCH CHANGE CONNECTING ROD. METALLURGICAL EXAMINATION OF THE SEPARATED PARTS DISCLOSED NO EVIDENCE OF ANY PREEXISTING CRACKING OR FATIGUE. THE POROSITY LEVEL OF THE VERTICAL FIN BULKHEAD CASTING WAS WITHIN NORMAL LIMITS.

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

THE PILOT'S INADEQUATE PREFLIGHT. CONTRIBUTING TO THIS ACCIDENT WAS THE SEPARATION OF THE FUEL CAP, TAIL ROTOR BLADE BALANCE WEIGHT, TAIL ROTOR GEAR BOX, AND THE VERTICAL FIN.

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