WF39: Perform Common Mode Analysis (CMA)

Pre-requisites

• SRA Module: access to the Safety and Risk Assessment (SRA) module enables a Hardware Fault Tree Analysis (FTA) to be generated.
• FBD Model: defined with functions and functional flows required to map out Fault Tree paths. Inclusion of failure diagrams would improve detail of Fault Trees (see WF06).

Detailed Descriptions (numbered steps)

1. Access 'Common Mode Analysis' under 'Analyses' in the main menu.
2. Click the green plus icon to create a Common Mode Analysis (CMA). Define a name, description (optional), select a system / sub-system as the level of indenture for the analysis, and left-click 'OK'.
3. Select the CMA Source Type(s) and, if necessary, the failure concept / flow property or model item. Click 'Search' to populate the Search Results table depending on the defined Search Options.
4. Review 'Search Results' and alter 'Search Options' if necessary.
5. Create Common Mode Event with the green plus icon. Define name, description (optional), select the model items to be included as common modes and click 'OK'.
6. Select the Common Mode Event and open with the open folder icon or double click it to open. Additionally, define requirements, if necessary.
7. Create Common Mode Failure with the green plus icon. Select the 'Failure Type' from the drop-down menu and define the 'Sub-type' accordingly.
8. Click the corresponding icons to open the dialogs to select the 'Source / Error' and 'Failure Condition' respectively. Further define Common Mode Failure details with text inputs for 'Justifications' and 'Mitigating Action'. Select the 'Status' to finalize.
9. Define all Common Mode Failures for the Common Mode Event.
10. Define all Common Mode Events for the Common Mode Analysis.

Fields referenced in the diagram

• Create Common Mode Analysis: Name, Description, Indenture Selection
• Conduct Search: RBD Group (Parallel), Failure Concept, Model Item
• Create Common Mode Event: Name, Description, Model Items
• Open Common Mode Event: Requirements
• Create Common Mode Failure: Failure Type, Failure Sub-type
• Define Common Mode Details: Source / Error, Failure Condition, Justification, Mitigating Action, Status

Decision points

• Search Successful? — No → loop back to Conduct Search; Yes → Create Common Mode Event.
• All Failures Defined? — No → loop back to Create Common Mode Failure; Yes → All Events Defined? decision.
• All Events Defined? — No → loop back to Create Common Mode Event; Yes → Common Mode Analysis Performed.

Outputs

• Common Mode Analysis Report: consists the entire CMA process outlining all defined common mode events and their associated common mode failures. It also includes summary page and all supporting documentation attached to the model items related to the analysis.

Screenshot walkthrough (captions/labels extracted)

Step 1: Access Common Mode Analysis

• 'Analyses' menu: Fault Tree, Response Paths, Connection Matrix, "Common Mode Analysis" (highlighted/cursor), Critical Item Analysis, Criticality & Reliability Editor, Technical Budget Analysis.

Step 2: Create Common Mode Analysis

• "Common Mode Analysis" tab: left nav Overview / Management. "Common Mode Analyses": "Select the buttons along the right side to create new, open existing, copy and delete Common Mode Analyses." Table (Name/Created) empty, add icon highlighted. "Analysis Details": Name, Description, Created Date (all empty). "Indenture Selection": "The settings applied to the Indenture Selection can not be changed once a CMA has been created." (empty field). "Common Mode Analysis Summary" (empty).
• "New Common Mode Analysis" dialog: "Enter the information below to create a new Common Mode Analysis." "CMA Details": Name "Training CMA", Description "An example CMA for training demonstration purpose." "Indenture Selection": "Select the System or Subsystem to include in the analysis. All items under the select system or subsystem will be included in the CMA. This selection influences the pathing analysis used to generate local, next and end effect information in the CMA report." Tree: Vehicle System > Driveline, "Power Generation" (checked/selected/highlighted) > Diesel Engine. Buttons OK, Cancel.

Step 3: Conduct Search

• "Common Mode Analysis" tab: "Search Options": "Select one or more search options below to narrow down the search results for the CMA." "CMA Source Type" checkboxes: Fault Tree Analysis, RBD Group, "Failure Concept" (checked), Model Item; note text explains "The current selection searches for failure concepts (Causes, Mechanisms, Faults, Symptoms) for items in the system. Results are listed in the Search Results and Events table." Button "Search". "Common Mode Events": Event Name, Status, Description, Requirement fields (empty). "Search Results & Events": "Select at least two or more items to be included into the Common Mode Events section or right-click these selected items to create a Common Mode Event." Table (Common Mode Items/Source Type(s)/Analysis Date) empty; "Common Mode Event/Source Type(s)/Status" table empty; instructional graphic "Drag model items to create an event."
• "Find Source/Error" dialog: "Select a Failure Concept or Flow Property below as the Source/Error and press OK to finish." Search field. Tree: Cause, Mechanism, Fault, "Failure Conditions" (expanded) — Intermittent operation, Failure to cease operation, Loss of output, Other; Flow Property > Energy, Material, Signal. Buttons OK (disabled), Cancel.
• "Find Model Item" dialog: "Select a model item (double-click or select item then OK) to include it as a CMA Source Type." Tree: Control Unit, Diesel Engine > Air Filter, Coupling 1, Engine, Governor, Injector Pump, Lift Pump, Primary Fuel Filter, Secondary Fuel Filter; Fuel Tank. Buttons OK, Cancel.
• Populated "Common Mode Analysis" view: "Search Options" CMA Source Type "Failure Concept" checked, value "Solid particle contaminants". "Search Results & Events" table (Common Mode Items/Source Type(s)/Analysis Date): "Current Search Result" ("Failure Concept: Cause: Solid par...", "2026/03/31 16:08:03") > Engine, Injector Pump, Lift Pump, Primary Fuel Filter, Secondary Fuel Filter.

Step 5: Create Common Mode Event

• "Search Results & Events" panel: table with "Current Search Result" expanded (Engine, Injector Pump, Lift Pump, Primary Fuel Filter, Secondary Fuel Filter); add/edit/delete icon buttons; empty "Common Mode Event" table on right with instructional graphic "Drag model items to create an event."
• "New Common Mode Analysis" dialog — "Create a new Common Mode analysis event": "Enter the details of the Common Mode analysis event." Name "New Event 1", Description "Example CMA for training". "Search Result:" dropdown "Current Search Result". "Common Mode Items": "Select two or more items to be included in the Common Mode Event." Tree "Current Search Result" (checked) > Engine (unchecked), "Injector Pump" (checked), Lift Pump (unchecked), "Primary Fuel Filter" (checked), "Secondary Fuel Filter" (checked). Buttons OK, Cancel.

Step 7: Open Common Mode Event

• "Common Mode Analysis" tab: left nav Overview/Management > Training CMA. "Search Options": CMA Source Type "Failure Concept" checked, "Solid particle contaminants". "Common Mode Events": Event Name "New Event 1", Status, Description "Example CMA for training", Requirement (empty). "Search Results & Events" table: "New Event 1" (Failure Concept: Cause: Solid par...) > Injector Pump, Primary Fuel Filter, Secondary Fuel Filter.
• Nested "Common Mode Analysis" tab: left nav Training CMA > "New Event 1" (selected). "CMA Worksheet - Event Information": Source Type "Failure Concept: Cause: Solid particle contaminants", Items "Injector Pump, Primary Fuel Filter, Secondary Fuel Filter", Requirements (empty). "Common Mode Failures" table (ID/Failure Type/Sub-Type/Source/Error/Failure Condition/Status) empty. "Common Mode Details" panel (empty): Failure Type, Sub-Type, Source/Error, Failure Condition, Failure Condition Narrative, Justification, Mitigating Action, Status (Independent/Dependent radio), Link to FTA.

Step 8: Create Common Mode Failure

• Two "Common Mode Details" panels shown with Failure Type dropdown expanded: "Design Architecture" (highlighted/selected) with options Design Architecture, Technology / Equipment, Specifications, Manufacturing, Installation / Integration, Testing / Calibration, Operation, Maintenance, Transportation, Environmental Factors.
• Second panel: Failure Type "Design Architecture", Sub-Type dropdown expanded: Mechanical Property, Electrical Property, Chemical Property, Hydraulic Loading, Pneumatic Loading, Software Property, Thermal Property.
• "CMA Worksheet - Event Information" with add icon tooltip "Create a new Common Mode Failure" highlighted; "Requirements: Design Requirements 1 - 10."

Step 8: Define Common Mode Details

• "Find Source/Error" dialog: tree Cause > Mechanism > Wear > Abrasive wear; Fault; Flow Property > Material > Liquid (selected) > Flow rate (highlighted). Buttons OK, Cancel.
• "Find Common Mode Failure Conditions" dialog: "Select a Failure Condition below and press OK to finish." Table (Failure Conditions/Failure Condition Description): "Liquid Flow rate [Secondary Fuel Filter]" (expanded) > "Loss of output" (selected, "When an item fails to provide output during operation."); "Liquid Flow rate [Primary Fuel Filter]" > "Failure to cease operation" ("When an item fails to cease functioning upon demand to do so."). Buttons OK, Cancel.
• "Common Mode Analysis" populated view: "CMA Worksheet - Event Information": Source Type "Failure Concept: Cause: Solid particle contaminants", Items "Injector Pump, Primary Fuel Filter, Secondary Fuel Filter", Requirements "Design Requirements 1-10." "Common Mode Failures" table: ID 1, Failure Type "Design Architecture", Sub-Type "Mechanical Property", Source/Error "Flow rate", Failure Condition "Loss of output", Status "Incomplete". "Common Mode Details": Failure Type "Design Architecture", Sub-Type "Mechanical Property", Source/Error "Flow rate", Failure Condition "Loss of output", Failure Condition Narrative "No fuel flow through the Secondary Fuel Filter", Justification "Common filter dimension.", Mitigating Action "Decrease inspection interval to 7 days.", Status radio Independent/Dependent (unset), Link to FTA (empty).

Step 9: All Failures Defined?

• "CMA Worksheet - Event Information" / "Common Mode Failures" table: three rows — ID 1 (Design Architecture, Mechanical Property, Flow rate, Loss of output, Status "Dependent"), ID 2 (Operation, Procedure, Perforated, Failure to cease operat..., Status "Independent"), ID 3 (Maintenance, Personnel, Insufficient cleaning, —, Status "Incomplete", selected/highlighted). "Common Mode Details": Failure Type "Maintenance", Sub-Type "Personnel", Source/Error "Insufficient cleaning", Failure Condition (empty), Failure Condition Narrative (empty), Justification (empty), Mitigating Action (empty), Status radio Independent/Dependent (unset).

Step 10: All Events Defined?

• "*Common Mode Analysis" (unsaved) tab: "Search Options" CMA Source Type "Failure Concept" "Solid particle contaminants". "Common Mode Events": Event Name "New Event 2", Status, Description, Requirement (empty). "Search Results & Events" table: "Current Search Result" ("Failure Concept: Cause: Solid particl...", "2026/03/31 16:25:11") > Air Filter, Engine, Injector Pump, Lift Pump, Primary Fuel Filter, Secondary Fuel Filter. Right "Common Mode Event" table: "New Event 1" (Failure Concept: Cause: Solid particl..., Status "Incomplete") > Injector Pump, Primary Fuel Filter, Secondary Fuel Filter; "New Event 2" (Failure Concept: Cause: Solid particl..., Status "Incomplete") > Engine, Lift Pump.

Step 11: Common Mode Analysis Performed

• "CMA REPORT SUMMARY": Name "Training CMA", Created Date "2020/06/08 13:32:11", Description "An example CMA for training purposes." "COMMON MODE EVENT SUMMARY" table: Total Dependent Events 0, Total Independent Events 0, Total Incomplete Events 1, Total Common Mode Events 1 (with pie chart). "COMMON MODE ITEM SUMMARY" table: Total Dependent Items 1, Total Independent Items 1, Total Incomplete Items 1, Total Common Mode Items 3 (with pie chart). "TARGET ITEM" Power Generation, "PHYSICAL DESCRIPTION" (blank), "FUNCTION" "Convert Mechanical - rotational Torque (Power Generation)", "FUNCTION NARRATIVE" (blank).
• Detail table: Event Name "New Event 1", Event Status "Incomplete", Event Items "Injector Pump, Primary Fuel Filter, Secondary Fuel Filter", Requirement "Design requirements 1 - 10.", Description (blank). Columns ID/Failure Type/Sub-Type/Source/Errors/Failure Condition/Failure Modes and Causes/Failure Effects (Next Effect/End Effect)/Justification/Mitigating Action/Status: Row 1 (Design Architecture, Mechanical Property, Flow rate, Loss of output, listing multiple failure modes e.g. "Low Liquid Flow rate due to outgrowing of the Secondary Fuel Filter as a result of buildup of debris caused by contaminated input flow and insufficient cleaning" etc.; Next Effect/End Effect "Convert Mechanical - rotational Torque Low (Diesel Engine)"/"(Power Generation)"; Justification "Common filter dimensions."; Mitigating Action "Decrease inspection interval to 7 days."; Status "Dependent"). Row 2 (Operation, Procedure, Perforated, Failure to cease operation, listing failure modes re corrosive attack/damaged surface protection/solid particle contaminants; Justification "High pressure differential due to solid contaminants from low-grade fuel."; Mitigating Action "None. Primary fuel filter has higher pressure limits than secondary filter."; Status "Independent").

Related workflows

• WF06 – Create Failure Diagram