NTSB Identification: NYC92IA035.
The docket is stored on NTSB microfiche number 50043.
Scheduled 14 CFR
Incident occurred Thursday, November 21, 1991 in BUFFALO, NY
Probable Cause Approval Date: 08/13/1993
Aircraft: SAAB-FAIRCHILD SF-340A, registration: N146CA
Injuries: 29 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
THE FLIGHT CREW DETECTED VIBRATION COMING FROM THE RIGHT PROPELLER AND MADE A DECISION TO SHUT THE ENGINE DOWN. DURING THE SHUTDOWN PROCESS THE PROPELLER SEPARATED FROM THE AIRPLANE. EXAMINATION OF BOTH PORTIONS OF THE FAILED PROPELLER SHAFT REVEALED THE SHAFT FAILED DUE TO FATIGUE. METALLURGICAL EXAMINATION FOUND A SLAG INCLUSION JUST BELOW THE FRACTURE SURFACE. THIS DEFECT OCCURRED DURING THE MELTING OF THE ORIGINAL INGOT.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: A FATIGUE FRACTURE ON THE PROPELLER SHAFT, THAT ORIGINATED AT A SUBSURFACE SLAG INCLUSION, WHICH REMAINED IN THE MATERIAL USED TO MANUFACTURE THE SHAFT.
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