NTSB Identification: ATL88IA171.
The docket is stored on NTSB microfiche number 37537.
Nonscheduled 14 CFR
Incident occurred Thursday, May 12, 1988 in REIDSVILLE, NC
Probable Cause Approval Date: 01/25/1990
Aircraft: AEROSPATIALE AS-355-F, registration: N101UC
Injuries: 4 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.

DURING CRUISE FLIGHT TAIL ROTOR BLADE SEPARATED FROM HELO DUE TO FATIGUE FAILURE OF THE COMPOSITE MATERIAL SPAR. THE TAIL ROTOR DRIVE SHAFT THEN SEPARATED AT THE TAIL ROTOR GEARBOX BECAUSE OF THE RESULTING MASS IMBALANCE. INVESTIGATION REVEALED THAT THE FATIGUE FAILURE PROPAGATED OVER APPROX 500 FLT HOURS. BONDING SEPARATION OF A SPAR REINFORCEMENT PAD WAS NOTED DURING AN OVERHAUL INSPECTION AT A REPAIR FACILITY. MAINT REQUIREMENTS DICTATED SPECIAL INSPECTIONS FOLLOWING DISCOVERY OF THE DEBONDING. THERE WAS NO PROCEDURE IN PLACE TO INFORM A CUSTOMER WHO RECEIVED THE ASSY AFTER OVERHAUL OF THE DEBONDING. THE OPERATOR NOTED IN HIS MAINT RECORDS CONTINUOUS PROBLEMS BALANCING THE TAIL ROTOR. CONTRARY TO MAINT INSTRUCTIONS TAIL ROTOR WAS LEFT IN SERVICE.

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

ROTOR SYSTEM,MAIN ROTOR BLADE..FATIGUE

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

ROTOR SYSTEM,TAIL ROTOR BLADE..SEPARATION


Contributing Factors

MAINTENANCE..IMPROPER..COMPANY MAINTENANCE PERSONNEL


Contributing Factors

MAINTENANCE,RECORDKEEPING..INADEQUATE..OTHER MAINTENANCE PERSONNEL

Index for May1988 | Index of months