The Australian Transport Safety Bureau (ATSB) has released a Safety Report containing the results of their initial investigation into a recent incident when a freefall lifeboat was unintentionally released. The investigation is ongoing and a final report containing recommendations will be issued and will be the subject of a further Class News. The report highlights the risk of release mechanisms being incorrectly reset following use or testing.
The Safety Report has identified that the JX-4 release mechanism, particularly the hydraulic hook release ram, did not always fully retract after use. If the ram is not fully retracted after use it may take significantly less cycles of the hydraulic hand pump to operate the hook release mechanism (four pumps rather than 12), which may lead to the lifeboat being released inadvertently or sooner than expected.
The system allows for the testing of the release mechanism at sea, without launching the lifeboat, by attaching ‘simulation wires’ through the aft quarters of the lifeboat. The simulation wires allow the hook mechanism to operate, release the lifeboat and then allow the lifeboat to travel approximately 150mm along the ramp, proving that the lifeboat will deploy. During the incident, the simulation wires failed at a load significantly below their rated safe working load. The cause of this premature failure has yet to be determined.
LR recommends that owners review their training and operating procedures to ensure that:
- all crew members and maintainers are aware of the need to ensure that hydraulic hook release rams are fully retracted after the system has been operated, and
- safety procedures are reviewed to reduce the risk to personnel if an inadvertent lifeboat release occurs.
Owners should study the recommendations of the final ATSB report when it is released.