WF37: Prepare Functional Hazard Assessment

Pre-requisites

• Functional Diagram: an opened and complete functional representation of the internal and external functions of the system, with all expected connections (see WF36).
• Association: defined / assessed failure conditions present in the Functional Diagram.
• Multiple Failure Event: defined / assessed failure conditions present in the Functional Diagram.
• Mission Profile: defined mission phases & segments and specialized phases, including Mission events, operational conditions and environmental conditions relevant to the system (see WF11).
• Safety Criteria: defined hazards and safety criteria in Project Preferences (see WF64).

Detailed Descriptions (numbered steps)

1. Open Failure Conditions Editor through the right-click context menu on an internal / external function to begin the Functional Hazard Assessment process.
2. If the function under assessment is impacted by failure condition(s) defined in other internal and external function(s), proceed to Step 2a. 2a. Select Functional Failure(s) and Failure Condition(s) from other internal and external functions that may impact the function under assessment.
3. Define functional failures for that function, starting with the existing one, created by default. Define the functional failure name with ID and failure effect for more information. Create additional functional failures with the 'add' button, defining Name and then a Failure Effect narrative.
4. If failure conditions are to be combined to create a multiple failure event, proceed to Step 5a.
5. Select a functional failure to create a failure condition, with the 'add' button. 5a. Create multiple failure event by combining multiple failure conditions from within the Functional Diagram for the selected functional failure. The event can be assessed like any other failure condition whereas the failure conditions involved in the event can only be edited in the function(s) they are created in.
6. Select the failure condition/multiple failure event to define the ID, name, type from the provided drop-down list, narrative, and whether it is reported for certification documentation. Level is inherited from the function it is created in.
7. Assign Mission Profile details in the 'Mission Profile' Tab by selecting the mission phases and segments and associating specialized phases related to the selected failure condition/multiple failure event. The Mission Profile is pre-selected and mission sections pre-populated based on the active mission profile of the project. Specialized phases are pre-populated for the selected mission sections.
8. Assign further Mission Profile details by selecting the mission events, operational conditions and environmental conditions related to the selected failure condition/multiple failure event. Capture crew awareness for more information.
9. If there are additional mission profiles, repeat Step 7 and Step 8 to define those mission profile details for the selected failure condition/multiple failure event.
10. Assign safety criteria and its associated hazard(s) to the failure condition/multiple failure event.
11. The failure condition(s) and multiple failure event(s) are prepared and ready to be assessed (see WF61).

Fields referenced in the diagram

• Define Functional Failure(s): ID, Name, Failure Effect
• Define Failure Condition/Multiple Failure Event: ID, Name, Type, Level, Narrative, Reported
• Assign Mission Profile Details: Mission Profile, Mission Sections, Specialized Phase
• Assign further Mission Profile Details: Mission Events, Operational Conditions, Environmental Conditions, Crew awareness

Decision points

• Associate Failure Condition(s) from other Functions? — Yes → Select Failure Condition(s) from other Functions; No → Define Functional Failure(s).
• Create Multiple Failure Event(s)? — No → Create Single Failure Condition(s); Yes → Create Multiple Failure Event(s).
• All Mission Profiles Defined? — No → loop back to Assign Mission Profile Details; Yes → Assign Safety Criteria.

Screenshot walkthrough (captions/labels extracted)

Step 1: Open Failure Conditions Editor

• Functional Diagram canvas: "New Function" box (selected, handles visible) above connected function boxes. Context menu: New; Import; Functional Diagram; "Failure Conditions" (highlighted); Open Domain Editor; Cut/Copy/Paste; Delete; Zoom In/Out; Link to System Model...
• Second canvas view: another function box (selected) with same context menu open, "Failure Conditions" highlighted; Domain Editor; Cut/Copy/Paste; Delete; Zoom In/Out; Link to System Model...

Step 2a: Select Failure Condition(s) from other Functions

• "Vehicle System" tab: left nav Functional Diagram > "*Control Vehicle" (selected) > Mission Profile, Events & Conditions, Safety Criteria, Failure Effect, Criticality > Control Measures, Revised Criticality, Assumptions, Substantiation Actions. "Failure Conditions" panel: "Select a Functional Failure or Failure Condition to view and edit its details." Table (Failure Condition/Mission Sections/Overall Effect/Initial Severity/Revised Severity): "1 - Inability to Control Vehicle" (highlighted) with right-click context menu: Add Functional Failure, Add Failure Condition, Create Multiple Failure Event, "Associate Failure Condition" (highlighted) / "Associate Failure Condition to Function" tooltip.
• "Failure Condition Association" dialog: "Associate Failure Conditions to the Function." Function "Control Vehicle". Search field. Tree: "2 - Provide Thrust" > Failure Modes > "1 - Inability to Provide Thrust", "2.1 - Covert Fuel to Mechanical Motion" (expanded) > Failure Modes > "1 - Inability to Covert Fuel to Mechanical Motion" > "1.1 - Failure Condition for Control Fuel", "1.2 - MFE for MADE training"; "2.2 - Distribute Mechanical Motion" (checked, expanded) > Failure Modes (checked) > "1 - Inability to Distribute Mechanical Motion", "2 - Inability to Distribute Mechanical Motion (Forward)" (checked) > "2.1 - Failure Condition 1" (checked, highlighted); "E1 - Environment", "E2 - Human Factors", "E3 - Support Systems" (expanded) > "E3.1 - Air/Ground Determinations" > Failure Modes > "1 - Inability to Air/Ground Determinations"; "E3.2 - Crew Alerting". Buttons OK, Cancel.

Step 3: Define Functional Failures

• "Vehicle System" tab: "Failure Conditions" panel table: "1 - Inability to Control Vehicle" (selected). Add-icon button (highlighted).
• "Properties" panel — "Inability to Control Vehicle": tabs General (selected)/Failure Condition Summary/Logical Links. ID (empty), Name "Inability to Control Vehicle" (edit icon), Function "Control Vehicle", Failure Effect (empty, edit icon).
• "MADE" dialog — "Create new Functional Failure": "Create a new functional failure for Control Vehicle" Function "Control Vehicle", Name field (empty, cursor active). Buttons OK (disabled), Cancel.

Step 5: Create Single Failure Condition(s)

• "Vehicle System" tab: "Failure Conditions" panel table: "1 - Inability to Control Vehicle" selected. Add (black circle) icon button highlighted (red box) among icon column: colored-circles icon, black-circle icon (highlighted), colored-circles icon, edit icon (disabled), arrows icon, copy icon, up/down arrows, delete icon.

Step 5a: Create Multiple Failure Event(s)

• Same "Failure Conditions" panel, icon column with the colored-circles ("multiple failure event") icon highlighted (red box).
• "Multiple Failure Event" dialog: "Combine failure conditions to create Multiple Failure Event." Function "Control Vehicle", Failure Mode "Inability to Control Vehicle". Search field. Tree: "2 - Provide Thrust" (expanded) > Failure Modes > "1 - Inability to Provide Thrust", "2.1 - Covert Fuel to Mechanical Motion" (expanded) > Failure Modes (expanded) > "1 - Inability to Covert Fuel to Mechanical Motion" (expanded) > "1.1 - Failure Condition for Control Fuel" (checked); "2.2 - Distribute Mechanical Motion" (expanded) > Failure Modes (expanded) > "1 - Inability to Distribute Mechanical Motion", "2 - Inability to Distribute Mechanical Motion (Forward)" (checked, expanded) > "2.1 - Failure Condition 1" (checked); "E1 - Environment", "E2 - Human Factors" unchecked. Buttons OK, Cancel.

Step 6: Define Failure Condition / Multiple Failure Event

• "Failure Conditions" panel table: "1 - Inability to Control Vehicle" (expanded) > "1.1 - Failure Condition 2", "1.2 - MFE for MADE Training" (expandable).
• "Properties" panel — "Failure Condition 2": ID "FC01", Name "Failure Condition 2", Type "Intermittent operation" (dropdown), Function Name "Control Vehicle", Level "AFHA", Narrative "Narrative for Failure Condition 2", Reported (checkbox checked).
• "Properties" panel — "MFE for MADE Training": ID "MFE01", Name "MFE for MADE Training", Type "Failure to cease operation" (dropdown), Function Name "Control Vehicle", Level "AFHA", Narrative "Narrative for the multiple failure event created by combining failure conditions from 'Convert Fuel to Mechanical Motion' and 'Distribute Mechanical Motion' functions.", Reported (checkbox checked).

Step 7: Assign Mission Profile Details

• "Vehicle System" tab: "Failure Conditions" table: "1 - Inability to Control Vehicle" > "1.1 - Failure Condition 1" (selected), Mission Sections "1 - Start-up, 1.1 - Ignition, 5.2 - Mountain Terrain". "Mission Profile" panel: "View and/or edit the details of Mission Sections and Specialized Phases for 1.1 - Failure Condition 1." Mission Profile "Regular Trip". "Mission Sections" tree: "1 - Start-up" (checked, expanded) > "1.1 - Ignition" (checked); "2 - Acceleration", "3 - Cruise", "4 - Turning" (unchecked); "5 - Cruise 2" (expanded) > "5.1 - Highway" (unchecked) > "5.1.1 - Highway A1", "5.1.2 - Highway B2" (unchecked); "5.2 - Mountain Terrain" (checked); "6 - Deceleration", "7 - Shut-down" (unchecked). "Specialized Phases" list (empty).

Step 8: Assign further Mission Profile Details

• "Events & Conditions" tab: "Failure Conditions" table: "1 - Inability to Control Vehicle" > "1.1 - Failure Condition 1" (selected), Mission Sections "2 - Acceleration". "Events and Conditions" panel: Mission Profile "Regular Trip", Operator awareness "Unspecified" (dropdown), checkbox "Filter by Mission Sections" (checked). "Mission Events": Search, Select All/Deselect All buttons; tree "Environmental" (checked) > "Heavy Rainfall and Flooding" (checked, selected). "Mission Conditions": Search, Select All/Deselect All buttons; tree "Operational Conditions" (checked) > "Engine Load" (checked).

Step 10: Assign Safety Criteria

• "Safety Criteria" tab: "Failure Conditions" table: "1 - Inability to Control Vehicle" (expanded) > "1.1 - Failure Condition" (selected), "2 - 2 - Inability to Distribute Mechanical Motion (F..." (Overall Effect "Failure of this function will prevent...", Initial Severity "Hazardous", Revised Severity "Minor"). "Safety Criteria" panel: "View and edit the details of the Safety Criteria for 1.1 - Failure Condition." Table (Category ID/Category Name/Hazard ID/Hazard Name/Hazard Description/Criticality/Safety Criteria/Minimum Safety Criteria): "ACC" / "Adaptive Cruise Control" — ACC_03 "Unintended acceleratio..." ("ACC system malfunction causing sudden ...", Major); ACC_01 "False sensing" ("Incorrect or unreliable sensor readings lea...", Catastrophic); ACC_02 "System lag" ("Delays in the ACC system's response to ch...", Hazardous). Safety Criteria column: "ACC system should maintain a safe and c...", Minimum Safety Criteria: "ACC system must maintain a minimum f...".

Related workflows

• WF11 – Create Mission Profiles
• WF36 – Create Functional Diagram
• WF61 – Assess Functional Hazard Assessment (referenced)
• WF64 – Define Safety Criteria (referenced)