LINCOLN, NE, USA
N4GH
Agusta A109
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.
Source: NTSB Aviation Accident Database
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