In-flight engine malfunction, 6 km south-south-east of Sydney Airport, New South Wales, on 25 August 2005, VH-TJX, Boeing 737-476

On 25 August 2005, while on a scheduled flight from Brisbane, Qld, to Sydney, NSW, a Boeing 737-476 aircraft, registration VH-TJX, experienced an in-flight engine malfunction approximately 6 km SSE of Sydney Airport.

An inspection of the left engine by the operator's engineering personnel revealed damage within the high-pressure compressor (HPC). The left engine, a General Electric CFM56-3C1, was subsequently removed and disassembled at the operator's maintenance facility. The teardown revealed that a single dowel pin had come loose from its installed position within stage-three of the HPC and was ingested by the downstream rotating hardware, resulting in damage to the HPC rotor and stator components.

Further examination of the HPC stator components revealed that the dowel pin had come loose due to excessive clearance and recession of the stage-three stator shroud anti-rotation pins.

As a result of this occurrence, the engine manufacturer, General Electric, initiated a number of safety actions that included a redesign of the HPC anti-rotation pin. The manufacturer also released an alert Service Bulletin CFM56-3 S/B 72-1091 to all operators and maintainers of CFM56-3 engines that recommended the introduction of the new pin design into existing engines. Other safety actions taken included amendments to the CFM56-3 maintenance manual for HPC stator shroud component inspections.