A McCauley Propeller Systems propeller hub with an area of transverse cracking extending through the hub mounting boss was received by the Australian Transport Safety Bureau (ATSB) from the Civil Aviation Safety Authority (CASA). CASA requested assistance from the ATSB to conduct an engineering examination of the cracked region.
The examination determined that the crack was the product of a high-cycle, low-stress fatigue mechanism, with the crack origin centred on a mounting stud hole. There were no associated defects or other anomalous features that may have assisted in the crack initiation.
Released in accordance with section 25 of the Transport Safety Investigation Act 2003.