NTSB Identification: MKC87IA070.
The docket is stored on NTSB microfiche number 35128.
Incident occurred Monday, March 30, 1987 in LINCOLN, NE
Probable Cause Approval Date: 07/10/1989
Aircraft: Agusta A109, registration: N4GH
Injuries: 3 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 PIC STATED THAT HE WAS GROUND TAXIING THE HELO TO THE RAMP AREA AT DUNCAN AVIATION TO SHUTDOWN FOR REFUELING. DURING THE TAXI, THE PIC HEARD A LOUD 'BANG' EMINATING FM THE REAR OF THE HELO. THE PIC LOWERED COLLECTIVE PITCH AND NO FURTHER NOISE WAS HEARD AND NO VIBRATION WAS FELT. THE PIC RE-APPLIED COLLECTIVE PITCH TO MOVE FORWARD WHEN THE HELO BEGAN TO YAW AND VIBRATE. AT THIS POINT THE PIC LOWERED COLLECTIVE TO FLAT PITCH AND SHUTDOWN THE ENG. REMOVAL REVEALED A BROKEN PORTION OF THE T/R DRIVESHAFT ABOUT 1 FT FORWARD OF THE GEARBOX. METALLURGICAL EXAMINATION BY THE NTSB LAB AND AN INDEPENDENT METALLURGIST CONCLUDED THAT THE DRIVESHAFT FAILED IN A MANNER CHARACTERISTIC OF TORSIONAL OVERLOAD. THE PIC STATED THAT NO CONTACT WITH THE GRND OR STATIONARY OBJECT HAD OCCURRED.
The National Transportation Safety Board determines the probable cause(s) of this incident to be:ROTOR DRIVE SYSTEM,TAIL ROTOR DRIVE SHAFT..OVERTORQUE
The National Transportation Safety Board determines the probable cause(s) of this incident to be:ROTOR DRIVE SYSTEM,TAIL ROTOR DRIVE SHAFT..FAILURE,TOTAL
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