Planned Maintenance System (PMS) and Auxiliary Machinery
The silent heart of onboard reliability: how to identify critical equipment under the ISM Code and turn maintenance from reactive into genuinely planned.
Operational Explanation
The Planned Maintenance System (PMS) translates into daily practice the ISM Code requirement to keep the ship and equipment in conditions consistent with applicable rules and Company instructions. Not all equipment carries the same weight, however: the ISM Code specifically requires identifying equipment and technical systems whose sudden operational failure may result in hazardous situations (critical equipment), reserving stronger reliability measures for it.
The distinction between critical and ordinary equipment is not merely formal: it determines the testing frequency of standby units, the minimum spare parts level to be carried on board, and the priority given during maintenance planning when resources (time, manpower) are limited.
Regulatory Reference
ISM Code, par. 10 (Maintenance of the Ship and Equipment), in particular par. 10.3: the Company must identify equipment and technical systems whose sudden operational failure may result in hazardous situations, including periodic testing of stand-by arrangements or equipment not in continuous use.
Scope of Application
Every piece of onboard machinery and technical system, with particular attention to auxiliary machinery (compressors, pumps, cooling systems, generators) whose continuous availability is not always as immediately visible as that of main machinery.
Procedure / How to Complete It
- Identify, with the Chief Engineer's involvement, the critical equipment according to ISM par. 10.3 criteria (sudden failure with potential hazardous situation).
- Schedule differentiated maintenance intervals in the PMS, with reinforced priority for the identified critical equipment.
- Periodically test stand-by units and equipment not in continuous use, not only the primary equipment.
- Record every maintenance intervention, including anomalies found and interventions postponed for lack of spare parts or time.
- Periodically review the critical equipment list, updating it after technical modifications or significant events (failures, near misses).
Practical Example
Example of identification: an auxiliary cooling pump for the main engine, classified as critical equipment since its sudden failure without a ready standby unit could lead to overheating and engine stoppage underway; tested monthly even when not in primary use.
Real Cases
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Critical equipment not explicitly identified, treated as ordinary maintenance | Maintenance/testing intervals insufficient relative to the real risk | Systematically apply the ISM par. 10.3 criteria to identify critical equipment |
| Standby units not tested because 'not in use' | A failure of the primary unit reveals that the standby also fails to work | Periodically test standby units too, not only those in continuous use |
| Maintenance interventions systematically postponed for lack of time, without tracking the impact on risk | Build-up of backlog maintenance on critical equipment | Explicitly track postponed interventions and their recovery priority |
PSC Observations
Operational Tips
- Always involve the Chief Engineer in the periodic review of the critical equipment list, don't leave it as a static document.
- Test standby units periodically with the same discipline applied to those in primary use.
- Explicitly track every postponed maintenance intervention, so as not to lose visibility on the accumulated backlog.
Checklist
- Critical equipment identified according to ISM par. 10.3
- Standby units tested periodically
- Maintenance interventions recorded, including anomalies and postponements
- Critical equipment list reviewed periodically
- Maintenance priorities reflect real criticality, not just available time