A Saab 340B passenger aircraft, registered VH-UYA, experienced a left engine malfunction during the take-off roll at Mount Isa airport. In response to the abnormal engine condition, the flight crew rejected the take-off and shut down the left engine. When the engine was subsequently disassembled by the engine manufacturer, it was revealed that a single stage-four power turbine blade had fractured at the blade root. The liberated airfoil section caused secondary damage to the power turbine and exhaust sections. Metallurgical analysis of the fractured blade revealed that a pre-existing crack had been present at the blade root for a significant period of engine operation prior to the incident malfunction.
