The Australian Transport Safety Bureau (ATSB) investigated an incident involving a vessel that lost propulsion while entering the Port of Fremantle, Western Australia, on 4 March 2025. The investigation examined the technical cause, maintenance practices, and communication factors that contributed to the occurrence.
What Happened
While under pilotage into the port, the vessel’s main engine stopped near the entrance to the Inner Harbour. Propulsion was temporarily restored but failed again shortly afterward inside the harbour. The ship continued under momentum while tug assistance was used to maintain control. After several attempts, the engine was restarted at dead slow ahead, and the vessel was safely berthed with tug support.
Why It Happened
The main engine failures were caused by degraded seals in the servo piston of the air distributor within the pneumatic control system. This defect allowed air leakage, misaligning the camshaft position and stopping the engine.
Several safety factors increased the likelihood of failure:
- The planned maintenance system lacked detail and did not include specific entries for the main engine pneumatic system.
- Manufacturer-recommended servicing of pneumatic components and the control air dryer was not carried out.
- Crew had not received specific training on pneumatic system maintenance.
- Communication issues arose because pilots used a non-standard radio channel for coordination with vessel traffic service (VTS), reducing effective contact during the emergency.
Actions Taken
- The engine manufacturer’s service team overhauled the complete pneumatic manoeuvring system at the vessel’s next port call.
- The operator initiated a review of its maintenance system, identifying 27 corrective actions and beginning a transition to a digital, class-approved planned maintenance platform.
- Fremantle Pilots and the port authority began reviewing communication protocols to align practices with designated VHF channels and benchmark against other Australian ports.
Lessons Learned
- A detailed and traceable planned maintenance system, aligned with manufacturer guidance, is essential to ensure the reliability of critical propulsion and control systems.
- Engineering personnel should be trained on specific systems such as pneumatic controls to maintain competency in inspection and upkeep.
- Regular servicing of components, including air distributors and control air dryers, is necessary to prevent failures caused by seal degradation, moisture ingress, or corrosion.
- Finally, strict adherence to established port communication protocols during emergencies is vital to enable timely and effective coordination between pilots, vessel traffic service, and supporting tugs.
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Source: ATSB
