WF20: Perform Model-based RCM Analysis

Pre-requisites

• Prepare RCM: to define contributors, select maintainable significant item, review FMEA, identify significant function, and select failure mode to continue RCM (see WF19).

Detailed Descriptions (numbered steps)

1. Categorize the failure mode selected in Step 7 of WF19 by answering a series of questions in the Failure Classification logic workflow and enter answer narrative.
2. Identify viable task types (scheduled/breakdown/failure finding/condition based/etc.) for the chosen failure mode by answering a series of questions in the task evaluation logic workflow and enter answer narrative. Click the plus icon to manually include additional task(s).
3. Define tasks to compute key analysis metrics. Import existing maintenance actions, if applicable, and assign to the chosen failure mode. For newly created actions, define effectiveness factor, cost metrics (cost of failure and/or detection) & its narrative, maintenance action details, task & personnel and equipment and consumables. Maintenance action details include ID, name, description, location of maintenance, and task interval.
4. Evaluate if the task will prevent the failure mode from occurring or reduce the consequence to an acceptable level using technical feasibility logic workflow.
5. Perform trade study for comparing cost and availability metrics (Mean Time Between Maintenance, Operational availability, Downtime) of all feasible tasks. Assign suitable task(s) to the failure mode. Successful task(s) is used for Reporting.
6. Select the next failure modes of the significant function in Step 7 of WF19 to initiate its assessment.
7. Select the next function of the maintenance significant item (MSI) in Step 6 of WF19 to initiate its assessment.
8. For the selected system, continue assessing the next maintenance significant item (MSI) identified in Step 3 of WF19.
9. RCM Analysis is performed for the selected MSIs.

Fields referenced in the diagram

• Define Task Details: Maintenance actions details, Task and personnel details, Equipment and consumables, Effectiveness factor, Cost metrics & its narrative

Decision points

• All failure modes assessed? — No → loop back to Prepare RCM analysis (WF19); Yes → All MSI functions assessed? decision.
• All MSI functions assessed? — No → loop back to Prepare RCM analysis (WF19); Yes → All MSI assessed? decision.
• All MSI assessed? — No → loop back to Prepare RCM analysis (WF19); Yes → RCM analysis performed.

Outputs

• Tasks within RCM analysis are compared against cost and availability metrics (Mean Time Between Maintenance, Operational availability, Downtime) — Trade Study.
• A comprehensive report in csv format describing all relevant steps in the analysis, decisions, and information — Generate Report.
• Key changes made by the contributors during the analysis are logged chronologically and available for review — Track Changes.
• Tasks assigned through RCM analysis are applied to the system model — Apply tasks to System Model.

Screenshot walkthrough (captions/labels extracted)

Step 1: Failure Classification

• "Model-based RCM - Analysis 1 (PHMT)": navigation arrows and failure mode dropdown "Low Mechanical - rotational Angular ...ngular velocity Low (Vehicle System)". Tabs: Failure Effect Category (highlighted)/Failure Classification and Task Evaluation. "Decision Tree": "1: Is Failure evident to Operating Crew?" — "Is the occurrence of the functional failure evident to the operating crew during the performance of normal duties?" narrative "Failure is not hidden", Yes selected. "2: Does the failure effect safety?" — "Does the functional failure or secondary damage resulting from the functional failure have a direct adverse effect on operating safety?" narrative "Loss of this function can have severe safety consequences", Yes selected. "5A: Lubrication / Servicing effective?" — "Is lubrication or servicing task applicable & effective?" (unanswered). "Failure Mode Details": Maintainable Item "Planetary Gearbox Rear", Failure Mode "Low Mechanical - rotational Angular ...al Angular velocity (Vehicle System)", Failure Effect Category "Evident Safety", Baseline P(f) "2.566491E-2", Severity "I", Adjusted P(f) "2.566491E-2" ("Model-based" dropdown). "Failure Effect Category Task" table (empty): Name/ID/Type/Technical Feasibil.../Int.../Do.../Cost/As...

Step 2: Identify Task(s)

• Same view with tabs expanded: Failure Effect Category / Lubrication and Servicing / Inspection/Functional check (subtabs "Scheduled - Service" / "Condition-based - Service"). Decision tree continues: "5A: Lubrication/Servicing effective?" Yes selected → green banner "Maintenance Task Added: Lubrication and Servicing". "5B: Inspection/functional check effective?" — "Is an inspection or functional check to determine degradation of function applicable & effective?" narrative "Regular inspections ensure early detection of issues", Yes selected → green banner "Maintenance Task Added: Inspection/Functional check". "5C: Restoration effective?" (partially visible, unanswered). "Failure Effect Category Task" table populated: "Inspection/Functional check" (ID 002, Type "Condition-based - Service", Interval "50 hr (2.083 ...", Downtime "2 hr (2 hours)", Cost $0.00, Assigned checked); "Lubrication and Servicing" (ID 001, Type "Scheduled - Service", Interval "0 hr (0 seco...", Downtime "0 hr (0 seco...", Cost $0.00, Assigned checked).

Step 3: Define Task Details

• Tabs: Lubrication and Servicing (highlighted, Scheduled - Service) / Inspection/Functional check (Condition-based - Service). "Failure Mode Metrics": Item MTTF "50.00 hours (2.083 days)", Baseline P(f) "2.566491E-2", Effectiveness Factor "0.05", Revised P(f) "2.438166E-2", Revised P(f) Narrative "Revised P(f) is acceptable". "Worksheet Summary": System Downtime "0 hr (0 seconds)", Proposed Interval "0.333 hr (20 minutes)", Task Cost "$600.00", Technical Feasibility "Pending". "Cost Metrics": Cost of Failure "$0.00", Cost Narrative "Scheduled maintenance, no failure cost involved". "Technical Feasibility Assessment" — "Applicability Criteria": "Does the replenishment of the consumable reduce the rate of functional deterioration?" (unanswered). "Maintenance Action Details": Action ID "001", Action Name "Lubrication and Servicing", Description "Perform lubrication and servicing activities on the maintainable item.", Location of Maintenance "Field", Maintenance Type "Scheduled - Service", Maintenance interval "20.000 minutes" (Direct Entry), Inspection interval "N/A hours". Tabs Maintenance/Inspection with sub-tabs Tasks and Personnel / Equipment and Consumables / Summary ("2.00 hrs / $200.00"). Table: 001 "Service maintainable item" (downtime checkbox, Duration 1.00 hr, Rate $100.00/person/hr, 1 Personnel, Total $100.00) with sub-row "Maintenance Engineer" ($100.00); 002 "Lubricate maintainable item" (1.00 hr, $100.00, 1 Personnel, Total $100.00) with sub-row "Maintenance Engineer" ($100.00).

Step 4: Assess Task Feasibility

• Same view, tab "Lubrication and Servicing" (Scheduled - Service) selected. "Worksheet Summary": Technical Feasibility now "Technically Feasible". "Technical Feasibility Assessment": Applicability Criteria "Does the replenishment of the consumable reduce the rate of functional deterioration?" Yes selected. "Effectiveness Criteria - Safety": "Does the task reduce the risk of failure?" Yes selected. "Effectiveness Criteria - Operational": "Does the task reduce the risk of failure to an acceptable level?" Yes selected. "Effectiveness Criteria - Economic": "Is the task cost-effective?" Yes selected. "Technically Feasible": "The RCM Task has been determined to be technically feasible."

Step 5: Task Selection

• "Trade Study" tab: "Maintainable Items" list: "Planetary Gearbox Rear". "Decision Summary": "Each task involves calculating item-level metrics based solely on its own data to perform effective trade studies. Updated metrics are utilized for availability calculations." Checkbox "Filter by Assigned Tasks". Table (Name/ID/Task Type/Cost/Downtime/Revised MTBM/Revised Ao/Revised FM Relia.../Assigned): "Store Mechanical - rotational Angular velocit..." > "Low Mechanical - rotational Angular velo..." (Revised FM Relia... 0.9756183) > "Inspection/Functional check" (002, Condition-based ..., $800.00, 0 hr (0 seconds), Revised MTBM 0.63, Revised Ao 1.0, Assigned checked), "Lubrication and Servicing" (001, Scheduled - Service, $450.00, 1.5 hr (1.5 hours), Revised MTBM 0.43, Revised Ao 0.4627788, Assigned checked). "Calculate" button: "Calculate the Failure Metrics for all the Maintainable Items, Failure Modes and Maintenance Tasks inside the RCM Analysis." "Summary Graph": four bar charts (Cost ~$800 vs ~$450; Downtime (Hours) ~0 vs ~1.5; Revised MTBM ~0.63 vs ~0.43; Revised Ao ~1.0 vs ~0.25) comparing the two tasks.

Track Changes

• "RCM Audit" tab: "Workflow - Completion Status" pie charts: Functions (Significant: 1, fully red), Failure Modes (Complete: 1, fully orange), Failure Effect Categories (Evident Safety: 1, fully red). "Audit Log" table with entries such as: "Store Mechanical - rotational Angular velocity" — Decision Tree Option changes for Safety/Environment Effect; "Low Mechanical - rotational Angular velocity due to cracking" — multiple Decision Tree Option changes (1: Is Failure evident to Operating Crew?, 2: Does the failure effect safety?, 5A: Lubrication/Servicing effective?, 5B: Inspection/functional check effective?) each with timestamps and Contributor "PHMT"; "Lubrication and Servicing" — Revised P(f) changed from 2.566491E-2 to 2.438166E-2, Effectiveness Factor changed from 0.0 to 0.05, Maintenance Interval changed from 0 hr to 20 min, Personnel Rate changed from $0.00 to $100.00; further Decision Tree Option changes for Applicability Criteria, Effectiveness Criteria (Safety/Operational/Economic); "Inspection/Functional check" — Cost of Detection changed from 0.00E+00 to 1.00E+02, Maintenance Interval changed from 0 hr to 0.5 hr, Inspection Interval changed from Model-Based 50 hr (2.083 days) to Direct Entry, Inspection Action Task Is Downtime changed from Yes to No, Maintenance Inspection Interval changed from 0.5 hr to 25 hr, Personnel Rate changed from $100.00 to $100.00.

Related workflows

• WF19 – Prepare Model-based RCM Analysis