Skip to main content

> Incident Pattern

Blind Process State (HMI Down, PLCs Running)

Supervisory HMI consoles crash or lose network connectivity while underlying autonomous PLCs continue executing physical process control. Operational Playbook (9-Step Protocol): 1. Contain: Isolate affected network boundaries or active sessions immediately to stop blast-radius expansion without tripping physical safety systems. 2. Understand Impact: Quantify clinical, physical, or financial exposure (patient health risk, MW generation lost, regulatory filing deadline implications). 3. Stabilize: Transition system to a deterministic safe fallback state (manual override, local HMI fallback, offline clinical forms). 4. Preserve Evidence: Capture forensically sound memory dumps, firewall PCAPs, audit logs, and hardware register states before rebooting. 5. Communicate: Activate pre-approved stakeholder escalation matrix (Lead Architect, Quality Head, CISO, Plant Director, and Regulatory Counsel). 6. Root Cause: Conduct systematic 5-Why and timeline fault-tree analysis isolating the mechanical, network, software, or procedural defect. 7. Corrective Action (CAPA): Develop, test in staging, and peer-review the validated remediation or engineering change order (ECO). 8. Prevent Recurrence: Implement automated fitness functions, hardware interlocking, or static code analysis gates in CI/CD or plant SOPs. 9. Verify: Conduct formal post-restoration verification testing and obtain independent Quality Assurance sign-off before closing incident record.

Definition

Supervisory HMI consoles crash or lose network connectivity while underlying autonomous PLCs continue executing physical process control.

Supervisory HMI consoles crash or lose network connectivity while underlying autonomous PLCs continue executing physical process control. Operational Playbook (9-Step Protocol): 1. Contain: Isolate affected network boundaries or active sessions immediately to stop blast-radius expansion without tripping physical safety systems. 2. Understand Impact: Quantify clinical, physical, or financial exposure (patient health risk, MW generation lost, regulatory filing deadline implications). 3. Stabilize: Transition system to a deterministic safe fallback state (manual override, local HMI fallback, offline clinical forms). 4. Preserve Evidence: Capture forensically sound memory dumps, firewall PCAPs, audit logs, and hardware register states before rebooting. 5. Communicate: Activate pre-approved stakeholder escalation matrix (Lead Architect, Quality Head, CISO, Plant Director, and Regulatory Counsel). 6. Root Cause: Conduct systematic 5-Why and timeline fault-tree analysis isolating the mechanical, network, software, or procedural defect. 7. Corrective Action (CAPA): Develop, test in staging, and peer-review the validated remediation or engineering change order (ECO). 8. Prevent Recurrence: Implement automated fitness functions, hardware interlocking, or static code analysis gates in CI/CD or plant SOPs. 9. Verify: Conduct formal post-restoration verification testing and obtain independent Quality Assurance sign-off before closing incident record.

Recognition Signals

  • •Unscheduled alarms
  • •Process variable deviation
  • •Audit trail discrepancies

Likely Impacts

  • •Regulatory non-compliance
  • •Production shutdown
  • •Emergency triage delay

Investigation Questions

  • •5. Communicate: Activate pre-approved stakeholder escalation matrix (Lead Architect, Quality Head, CISO, Plant Director, and Regulatory Counsel).
  • •6. Root Cause: Conduct systematic 5-Why and timeline fault-tree analysis isolating the mechanical, network, software, or procedural defect.

Containment Guidance

  • •1. Contain: Isolate affected network boundaries or active sessions immediately to stop blast-radius expansion without tripping physical safety systems.
  • •2. Understand Impact: Quantify clinical, physical, or financial exposure (patient health risk, MW generation lost, regulatory filing deadline implications).
  • •3. Stabilize: Transition system to a deterministic safe fallback state (manual override, local HMI fallback, offline clinical forms).
  • •4. Preserve Evidence: Capture forensically sound memory dumps, firewall PCAPs, audit logs, and hardware register states before rebooting.

Remediation Guidance

  • •7. Corrective Action (CAPA): Develop, test in staging, and peer-review the validated remediation or engineering change order (ECO).

Prevention Guidance

  • •8. Prevent Recurrence: Implement automated fitness functions, hardware interlocking, or static code analysis gates in CI/CD or plant SOPs.
  • •9. Verify: Conduct formal post-restoration verification testing and obtain independent Quality Assurance sign-off before closing incident record.
Filter all episodes by this pattern →

FAQ

What is the very first containment action for this incident?

1. Contain: Isolate affected network boundaries or active sessions immediately to stop blast-radius expansion without tripping physical safety systems.

AEO Summary

Operational incident playbook for Blind Process State (HMI Down, PLCs Running) providing 9-step root cause analysis, immediate containment, and CAPA remediation guidance.

AI Summary

Blind Process State (HMI Down, PLCs Running) represents an operational breakdown in mission-critical environments. Resolution demands adherence to the strict 9-step incident management lifecycle.