NTSB Identification: LAX91LA135.
The docket is stored on NTSB microfiche number 44981.
Accident occurred Sunday, March 17, 1991 in HERLONG, CA
Probable Cause Approval Date: 01/25/1993
Aircraft: MOONEY M20D, registration: N1921Y
Injuries: 3 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 AIRCRAFT HAD BEEN IN CRUISE FLIGHT AT AN ALTITUDE OF 7500 FEET MSL FOR TWO AND A HALF HOURS WHEN A BLADE SEPARATED FROM THE FIXED PITCH PROPELLER. THE PILOT SECURED THE ENGINE, STOPPED THE ROTATION OF THE PROPELLER AND LANDED ON A ROAD WITHOUT FURTHER INCIDENT. A POST ACCIDENT ANALYSIS OF THE PROPELLER FAILURE DISCLOSED A FATIGUE CRACK EMANATED FROM A CORROSION AREA ON THE CAMBER SIDE OF THE BLADE.

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

THE INADEQUATE PREPARATION OF THE PROPELLER DURING OVERHAUL. THE INSTALLATION OF AN IMPROPER PITCHED PROPELLER AND THE FATIGUE FAILURE OF THE PROPELLER BLADE EMANATING FROM CORROSION WERE FACTORS IN THE ACCIDENT.

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