MADE Training > Session 3 > Session 3.6: Common Mode Analysis (CMA)

Session 3.6: Common Mode Analysis (CMA)

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SESSION 3.6 OUTLINE

3.6.1: CMA in ARP4761 Context 3.6.2: CMA Editor Layout 3.6.3: Common Mode Item Search 3.6.4: Common Mode Events 3.6.5: CMA Worksheet 3.6.6: CMA Report

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6 COMMON MODE ANALYSIS PRE-REQUISITE

Pre-requisite: Add the Failure Condition Failure to Cease Operation to Perforated Fault in `Primary Fuel Filter' component failure diagram. This piece of information will be used in the analysis.

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6 COMMON MODE ANALYSIS PRE-REQUISITE

Pre-requisite: Add the Failure Condition Loss of output to Blocked Fault in `Secondary Fuel Filter' component failure diagram.

Failure Narrative: No fuel flow through the Secondary Fuel Filter

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.1 CMA IN ARP4761 CONTEXT

ARP4761 Standard: Guidelines & methods of performing safety assessment for certification of civilian aircraft

CMA Definition: Verify that ANDed events in FTA, Dependence Diagrams (DD) & Markov Analysis (MA) are independent in the actual implementation

   Analyse effects of Design, Manufacturing, Maintenance errors & Failures of components which defeat their
     independence

   Consider independence of functions & their respective monitors

          E.g. Items with identical hardware/software could be susceptible to the same faults

Performed during Concept and Preliminary Design Stages

CMA is performed at 2 levels: Platform (e.g. Aircraft) Level & System Level

Pre-requisites: BOM/FBD Model, Failure Diagrams, RBD Groups

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.2 COMMON MODE EDITOR LAYOUT

The default layout of the CMA editor consists of:

Vertical Tabs (Left): Overview, CMA Events & Common Mode Event Worksheet pages Overview Page: Displays a list of CMAs including CMA details & a pie chart Analysis Page: Displays search options & results, and Common Mode Events Worksheet Page: Displays Common Mode Failures & details

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.2 CREATE A COMMON MODE ANALYSIS

To create a new CMA:

Select Analyses Common Mode Analyses from the main menu

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.2 CREATE A NEW CMA

From the Overview page:

Select to create a new Common Mode Analysis From the dialog:

   Enter Name: Training CMA
   Enter Description: An example CMA for training purposes.
   Select Indenture: `Power Generation'
   Select

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.3 COMMON MODE ITEM SEARCH

The Analysis page is used to conduct an initial search of items based on 3 criteria:

   Items arranged in a Parallel RBD group (covered in Session 4.3)
   Items with common failure concepts
   Searching for items by display name

Candidate items are grouped into a Common Mode Event for further evaluation in the Worksheet page

Common Mode Events are also used to capture:

   Description of common mode items
   Relevant requirements if applicable (see ARP4761 examples)

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.3 COMMON MODE ITEM SEARCH

In the Search Options section:

Select the Failure Concept check box

Select the Failure Concept Icon to browse for a relevant failure concept

From the dialog search for Solid Particle Contaminants

Select the Cause Failure Concept under Cause Operation Contamination

Select to close dialog

Select button

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.3 COMMON MODE ITEM SEARCH (CONTINUED)

Verify that the Search Results & Events table displays a current search result below

Note: Primary Fuel Filter' will not appear due to the failure diagram override. To deactivate failure diagram override, right click the Primary Fuel Filter' component from the Project Explorer and select Override Failure Diagram.

Once this has been done, select to re-run the search results

Verify that `Primary Fuel Filter' is displayed in the search results

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.4 COMMON MODE EVENTS

Common Mode Events are used to aggregate selected items for further analyses Each CMA can have multiple Common Mode Events Each Common Mode Event stores the following information:

   Event Name
   Event Description
   Event Requirements
   List of items
   CMA Worksheet data

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.4 CREATE A COMMON MODE EVENT

In the Search Results & Events section:

Highlight 3 components: Injector Pump', Primary Fuel Filter' & `Secondary Fuel Filter'

   Ctrl + Left Select

There are 3 methods to create a Common Mode Event: Method 1: Drag-and-drop selected items to the Common Mode Event table Method 2: Right-click and select Create New Event Method 3: Select and from New Common Mode Event dialog:

          Enter an Event Name
          Enter an Event Description
          Select Item check boxes to include into CMA
          Select

Open Common Mode Event: Select or Double-click Event

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.5 CMA WORKSHEET

This page captures common mode failures for items included in the Common Mode Event

Common Mode Failure details include:

   Failure Type/Sub-type (As per ARP4761 & CMA Literature)
   Failure Source/Error: Common Failure Concepts
   Failure Conditions & Narratives
   Failure Justification: Explain how this common mode failure occurs for all items
   Mitigating Action: What must be done to prevent this common mode failure from happening
   Status: whether a common mode failure is dependent/independent

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES

Create a new Common Mode Failure by selecting Verify common mode failure in first row of table with ID of 1 & Status: Incomplete

For Requirements, input the Requirements: Design requirements 1-10. Select Failure Type & Sub-Type: Design Architecture, Mechanical Property Select Source/Error icon to open dialog:

   Search for Flow Rate (Flow Property  Material  Liquid) then select

Select Failure Condition: Loss of output Enter Justification: Common Filter dimensions Enter Mitigating Action: Decrease inspection interval to 7 days. Select Status: Dependent

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES (CONTINUED)

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES (CONTINUED)

Create a second Common Mode Failure by selecting

   Verify common mode failure in first row of table with ID of 2 & Status: Incomplete

Select Failure Type & Sub-Type: Operation, Procedure Select Source/Error icon to open dialog:

   Search for Perforated (Fault  Perforated) then select

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURE (CONTINUED)

Select Failure Condition: Failure to cease operation Enter Justification: High pressure differential due to solid contaminants from low-grade fuel. Enter Mitigating Action: None. Primary fuel filter has higher pressure limits than secondary filter. Select Status: Independent

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES (CONTINUED)

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES (CONTINUED)

Create a third Common Mode Failure by selecting

   Verify common mode failure in first row of table with ID of 3 & Status Incomplete

Select Failure Type & Sub-Type: Maintenance, Personnel Select Source / Error icon to open dialog:

   Search for Insufficient cleaning (Maintenance  Procedure) then select

Leave all other fields blank Verify Status for current Common Mode Failure as Incomplete Return to Overview/Management tab

   Verify Common Mode Analysis Summary Graph

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.5 CREATE COMMON MODE FAILURES (CONTINUED)

Session 3.6: Common Mode Analysis (CMA)

DISCUSSION 3.6.6 CMA REPORT

This report summarises each CMA, including Common Mode Events & Items The CMA Report is divided into sections:

   CMA Report Summary
   Common Mode Events
   Reference Documents, Drawings & Support Material

Session 3.6: Common Mode Analysis (CMA)

EXERCISE 3.6.6 GENERATE CMA REPORT

To generate a CMA Report: From the menu bar, select Report Report Wizard Select Common Mode Analysis then select Verify CMA Analysis: Training CMA Verify Common Mode Event: New Event 1 Select

Session 3.6: Common Mode Analysis (CMA)

SESSION 3.6 SUMMARY

3.6.1: CMA in ARP4761 Context 3.6.2: CMA Editor Layout 3.6.3: Common Mode Item Search 3.6.4: Common Mode Events 3.6.5: CMA Worksheet 3.6.6: CMA Report

Source: Local MADE 3.9.1 installation: com.phm.made.help.plugin/documents/help/pdf/MADE Training Session 3.pdf · retrieved 2026-07-09