What TECHOP D-02 is
The MTS DP Committee published TECHOP D-02 (Rev1, January 2021) on FMEA testing. It addresses DP FMEA proving trials and the tests needed to validate the redundancy concept of DP Class 2 and DP Class 3 vessels (D-02 §2.1.1). Proving trials are meant to confirm that the DP FMEA correctly predicts how the DP system operates and fails, and that the system has every attribute its fault tolerance depends on (§4.4.3).
The case for action is historical. D-02 points to a long record of blackouts and other DP incidents caused by a small group of failure modes that can defeat the redundancy concept of a diesel electric plant run as a common power system, with closed busties (§3.1.1). Some of the same failure modes can also exceed the worst case failure design intent on DP Class 3 vessels running with busties open (§3.1.2).
Alongside its testing guidance, D-02 includes a gap analysis tool for judging whether the scope of a proving trials program is adequate (§2.1.2, §5.1.3). The gap analysis checks the scope and methodology of the trials program against published industry guidance. It does not repeat or correct the analysis, and it is typically carried out using only the FMEA and the trials program as source material (§4.18.1).
D-02 and D-05 work together. D-02 notes that its tool may be used in combination with the DP FMEA gap analysis tool to identify whether additional analysis and tests are required (§3.2.2). GapAnalyzer runs both: this page covers the trials program, and the D-05 FMEA gap analysis covers the FMEA itself.
What the checklist covers
The MTS D-02 checklist has 16 preamble items, which check that the trials document sets out its basis (trials conditions, class notation, redundancy concept and worst case failure design intent, acceptance criteria, drawing and software references), and 100 content items grouped by sub-system:
Behind the list sit the four attributes a redundancy concept depends on, and which the tests in a trials program must prove: performance, protection, detection and fail-safe (§4.8.2 to §4.8.6). D-02 also names tests it expects where they are needed to prove redundancy. For closed bus plants these include voltage dip ride through after a short circuit and earth fault, critical active and reactive power imbalance, critical line current imbalance, and load acceptance and rejection (§4.10). For all DP Class 2 and 3 designs they include control network redundancy and storm testing, and automatic blackout recovery where it is required (§4.11).
Not every item applies to every vessel. The checklist marks each item against closed busties, open busties and DP Class 3 (§4.18.10). GapAnalyzer takes the vessel's DP class and bus-tie configuration at upload and marks items that do not apply as not applicable.
How findings are graded
D-02 uses a four-colour scheme for the trials program (§4.18.3). GapAnalyzer's verdicts map onto it one to one:
| D-02 colour | Meaning in D-02 | GapAnalyzer verdict |
|---|---|---|
| Green | Test procedure satisfactory | YES |
| Yellow | Test procedure incomplete | PARTIAL |
| Red | Test omitted or contains significant errors | NO |
| Grey | Not applicable to this vessel's design | N/A |
D-02 gives an example of a significant error: omitting to test or simulate a failure mode with potential effects exceeding the worst case failure design intent (§4.18.4). With grey items discounted, the share of yellow and red findings gives the level of deficiency as a percentage (§4.18.8). GapAnalyzer reports that deficiency figure as D-02 defines it, with the green, yellow and red shares behind it, and adds no score or grade of its own.
Why a D-02 review takes specialist time
Each of the 116 items needs a judgement from someone who knows how DP redundancy is proven. D-02 acknowledges that it may not be obvious from the documents whether equipment is not fitted to the vessel or is fitted but its test has been left out. Its rule is that an omission which could conceal failure effects more severe than the worst case failure design intent is red, and one with no significant impact on severity is grey (§4.18.5). Making that call item by item, with the FMEA, the trials program and the checklist open side by side, is work for an experienced DP engineer, and it has to be booked and paid for before the findings can even be discussed.
| Manual D-02 review | GapAnalyzer | |
|---|---|---|
| Who does it | An experienced DP engineer, booked in advance | Automated, run when the draft program arrives |
| Coverage | Depends on the reviewer's attention across 116 rows | Every item evaluated, every time |
| Traceability | Comments in a spreadsheet | Each verdict cites the section it relied on; click through to the source page |
| Consistency | Two reviewers produce two different gap lists | The same criteria applied to every item on every run |
| Deliverable | Filled MTS D-02 workbook and a summary | Filled MTS D-02 workbook, PDF report and the D-02 deficiency figure |
On consistency: in our MarCompBench study, two DP experts and a maritime consultancy assessed the same DP operations manual against the same MTS checklist and agreed on roughly half the items. Reviewer variation is a property of the task, not of any one reviewer.
What you get
The MTS companion spreadsheet for FMEA testing with the verdict, the supporting evidence from the trials program and a comment on every row.
Each finding points to the section of the document it relied on. Open it and the source page sits beside the assessment, so findings can be checked rather than trusted.
Where the program has no test for an item, the verdict is No with an explanation of what is missing. The analysis is instructed to cite only your program, and every citation links to the passage it came from, so you can check it.
The deficiency percentage from §4.18.8 and the number of yellow and red findings to confirm, each labelled with the paragraph it comes from.
Step one, done properly
D-02 sets out the process for acting on a gap analysis (§4.19.1). The first step is to carry out the gap analysis. The second is to confirm any yellow and red findings against the original vessel design documentation. After that comes additional failure modes and effects analysis where needed, and, if unacceptable failure effects are found, either an update to the trials program for a new build or mitigation through design, operations and people for a vessel in service. The flowchart in D-02 ends with the program reported as satisfactory whenever the review does not confirm the findings.
GapAnalyzer does the first step. Your DP engineer, or the assurance firm you already use, starts from a complete, cited D-02 table and spends their hours confirming findings and deciding what to do about them.
When to run it
D-02 is specific on timing: the most useful point is the draft revision of the trials program, when it reaches the vessel owner for review and before it is submitted to Class. After Class has approved it with comments, it may be difficult to influence further development (§4.18.10, note). If the vessel has already entered service, the analysis is performed on the completed trials program and the findings are handled through the mitigation process (§4.19).
Who uses it
Owners and new-build teams reviewing a draft trials program from the yard or the FMEA contractor before Class submission. Operators checking the completed program of a vessel in service. DP assurance firms using an independent first pass so their engineers spend time on the findings that matter.
Frequently asked
The scope and methodology of a DP FMEA proving trials program against published industry guidance. It does not repeat or correct the analysis, and it uses the FMEA and the trials program as its source material.
Yes. D-02 covers that case: the analysis is performed on the completed trials program, and confirmed findings with unacceptable failure effects are mitigated through design, operations and people.
D-02 suggests combining the two tools to identify whether additional analysis and tests are required. GapAnalyzer runs the D-05 FMEA gap analysis as a separate analysis on the FMEA itself.
The proving trials program as PDF or DOCX, with the vessel's DP class and bus-tie configuration. Scanned documents are run through OCR first.
Documents are stored on our own servers in the EU, no human reads them during analysis, and our model providers do not train on them. The details, including sub-processors and NDAs, are in the main FAQ.