NTSB Identification: ANC93FA064.
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Nonscheduled 14 CFR
Accident occurred Monday, May 17, 1993 in MALINA BAY, AK
Probable Cause Approval Date: 06/30/1994
Aircraft: FAIRCHILD FH-1100, registration: N5060F
Injuries: 2 Serious,2 Minor.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.

EXAMINATION OF THE HELICOPTER SHOWED THAT THE ENGINE TO TRANSMISSION DRIVE SHAFT, ENGINE SIDE COUPLING FAILED. METALLURGICAL ANALYSIS SHOWED FATIGUE FRACTURE SURFACES BUT DUE TO THE ROTATIONAL DAMAGE, THE ORIGIN OF THE FRACTURE COULD NOT BE DETERMINED. THE EXAMINATION ALSO SHOWED MANY STAMPED NUMBERS PEENED OVER WITH A DIFFERENT NUMBER. HOWEVER, THE BENDIX DATA PLATE WAS STILL AFFIXED TO THE SHAFT AND SHOWED THE PART NUMBER 19E49-3E. EXAMINATION OF THE HELICOPTER RECORDS SHOWED THAT A DIFFERENT SERIAL NUMBERED SHAFT WAS SUPPOSED TO BE INSTALLED. ACCORDING TO THE SERVICE RECORD OF THE SHAFT ACTUALLY INSTALLED, IT DID NOT SEE ANY SERVICE FROM JULY, 1978 TO MARCH, 1992. DOCUMENTATION WAS NOT FOUND SHOWING THE DRIVE SHAFT HAD BEEN MAINTAINED IN ACCORDANCE WITH APPLICABLE SERVICE LETTERS AND BULLETINS.

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

THE INSTALLATION OF A BOGUS TRANSMISSION TO ENGINE DRIVESHAFT. THE FAILURE OF THE COMPANY MAINTENANCE PERSONNEL TO COMPLY WITH THE SERVICE BULLETINS AND LETTERS WAS A FACTOR.

Full narrative available

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