Transport Malta’s Marine Safety Investigation Unit (MSIU) issued an investigation report, concerning an engine explosion on board a passenger vessel, that caused severe burn injuries to two persons, on May 2016. The purpose of the report is to determine the circumstances of the accident, as a basis for making recommendations, in order to prevent further incidents from occurring in the future.
The incident:
Two motor mechanics, from the Company’s workshop were sent on board MV Delfini, to investigate an engine problem reported by the vessel’s skipper and engine driver. Work was necessary on the port main engine to identify and eliminate the exhaust white smoke, which was being emitted by the engine under load conditions.
The mechanics dismantled the port main engine turbocharger and exhaust manifold as they suspected that the problem was caused by faulty injector(s) on either one or more of the units. To troubleshoot the faulty fuel injector valve(s), the engine was started on idle speed with these parts removed.
In the process, one of the two mechanics suffered severe burns to his face, hands and chest, while his colleague sustained a superficial injury to his forehead, caused by the explosion and fire that escaped from the engine exhaust ports.
Acceptance of risk
The practice of removing the exhaust manifold and turbocharger and start the engine is dangerous and not a recommended maintenance practice. Notwithstanding, the no alternative measures were adopted. The risks associated with the actual actions taken by the two shore-based maintenance personnel were either accepted or not understood. The safety investigation is of the view that there were various reasons behind this.
As indicated elsewhere in this safety investigation report, the dismantling of the exhaust manifold to identify an offending fuel injector was not a one-off for the Company. The MSIU’s understanding was that this practice had always worked and there was actually no reason why the procedure should have failed this time. The Company’s shore-based maintenance personnel had no idea which of the injector(s) was faulty, even because there was no planned maintenance to which they could refer in terms of running hours. Moreover, they only had four reconditioned fuel injectors and therefore they would have been unable to replace the entire set.
As much as it was a valid technical option, the shutting down of each cylinder was not deemed to be possible from a practical perspective, given that the necessary equipment / resources were either not available or not made available to the mechanics working on board. The MSIU believes that the personnel involved were convinced that the removal of the exhaust manifold would have provided an immediate indication as to which of the six was the offending fuel injector(s). The decision to overhaul the exhaust manifold was therefore based on a rational decision and was seen and considered to be a reasonable option to solve the problem with the main engine.
Restricted accessibility around the port main engine
Conclusions:
- When the engine was stopped for the night, the faulty fuel injector(s) may have leaked minute droplets of fuel onto the piston crown.
- When the engine was started, the following morning (with the exhaust manifold and turbocharger removed), the fuel late ignition escaped through the exhaust ports, producing an afterburning flame that injured the mechanic.
- There was no planned preventive maintenance system for the engine-room machinery.
- The Company did not provide Cummins engine specific training courses to its mechanics.
- The operation and maintenance manual for the Cummins main engines was not available on board Delfini.
- While working in the engine-room, the younger mechanic had taken off his top, thereby compromising his protection
- No responsible person had been designated in charge of the maintenance work that was to be performed on the port main engine.
- No risk assessment was carried out to identify any risks that could be encountered during the work on the port main engine.
- The dismantling of the exhaust manifold to identify an offending fuel injector was not a new procedure to the Company.
- The risks associated with the actual actions taken by the two shore-based maintenance personnel were either accepted or not understood.
- The shutting down of each cylinder was not deemed to be possible from a practical perspective, given that the necessary equipment / resources were either not available or not made available to the shore-based maintenance personnel working on board.
- The personnel involved were convinced that the removal of the exhaust manifold would have provided an immediate indication as to which was the offending fuel injector.
- The decision to overhaul the exhaust manifold was therefore based on a rational decision and was seen as a reasonable option to solve the problem with the main engine.
Dismantled exhaust manifold, turbocharger and exposed exhaust ports
Recommendations
Supreme Travel Ltd. is recommended to adopt and implement:
- a planned maintenance regime on all Company operated vessels, in accordance with recommended maintenance schedules.
- a health and safety policy to ensure that all Company employees implement relevant procedures.
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Source: Transport Malta
