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Summary

Summary

At 1215 Eastern Standard Time on 27 September 2004, the pilot of a Kawasaki Heavy Industries, 47G3B-KH4 helicopter, registered VH-MTF, was being operated on a tourist flight with two passengers in north-west Tasmania. The pilot reported that as he brought the helicopter to a 1 m hover above the raised landing platform, the helicopter began to rotate slowly to the right. The pilot unsuccessfully attempted to counter the rotation by applying left tail rotor control input. The pilot then increased engine power, however, that action had the effect of rapidly increasing the rotation of the helicopter to the right and the helicopter climbed to about 5 m above the ground. After the pilot lowered the collective control the helicopter impacted the ground heavily on its right side. The pilot and passengers received minor injuries.

The helicopter's tail rotor drive shaft had failed during the occurrence. ATSB specialist examination of the failed drive shaft, attributed the failure to damage from a significant torsional overload event, leading to the shear fracture of the shaft. The examination was unable to determine when the torsional overload occurred, however, examination of the wreckage indicated that it was likely that it had occurred prior to this accident

Information received from the operator and from the maintenance organisation indicated that there had been no known tail rotor strike or sudden rotor stoppage since the helicopter was placed on the Australian aircraft register in 1992. The helicopter's history prior to that time was not examined.

The action of the pilot in increasing engine power when faced with the loss of tail rotor thrust was also examined.

 
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