When Maintenance Fails, Chaos Takes Off: Inside The Heathrow Substation Fire

On March 20, 2025, a fire at National Grid’s North Hyde substation plunged Heathrow Airport into darkness, grounding more than 270,000 passenger journeys and costing airlines up to £100 million. An independent review has now revealed the root cause: lack of maintenance of moisture-laden transformer bushings – first flagged seven years ago – that were repeatedly left in service, with “basic maintenance” deferred as recently as 2022.

The report highlights two systemic gaps. First, National Grid lacked visibility into how critical the asset was to Heathrow’s operations. Second, once abnormal moisture was detected, no risk-based work order was triggered – despite the vendor’s own guidance that the component faced “imminent fault”. These missed signals illustrate why relying on time-based inspections alone is no longer tenable for critical national infrastructure.

Verdantix research explores the role of digital solutions – such as asset performance management (APM), enterprise asset management (EAM) and computerized maintenance management system (CMMS) software – which fuse asset-criticality scoring with real-time condition data, predictive analytics and AI copilots to deliver proactive, risk-centered maintenance strategies. Once an equipment anomaly is flagged, the workflow can push a high-priority work order into either an EAM or CMMS for work order execution along with financial information about the cost and consequences involved. Had National Grid’s transformer moisture alerts flowed through such an APM/EAM layer and been routed into the appropriate CMMS or EAM work order system, a controlled outage could have replaced the faulty bushing and averted the £100 million shutdown.

The same risk-centric ethos underpins the asset integrity and risk management solutions profiled in our Smart Innovators report. These platforms consolidate inspection planning, integrity operating windows and probabilistic risk assessment across complex asset fleets. For utilities, this means shifting from subjective ‘fit-for-service’ calls to data-driven decisions: replacing a bushing when moisture crosses a pre-defined threshold, not when a calendar says so.

To operationalize these insights, firms should prioritize five actions:

1. Map asset criticality to business impact.
   Heathrow’s operators knew the substation’s importance, but National Grid did not. A shared CMMS/EAM hierarchy linking asset IDs to process consequences would have closed this gap.
   
   
2. Instrument condition monitoring.
   Online dissolved-gas or moisture sensors feeding straight into reliability dashboards can trigger alerts long before catastrophic limits.
   
   
3. Adopt risk-based work planning.
   Coupling criticality scores with real-time health indices helps maintenance teams justify proactive outages before failure risk outweighs production loss.
   
   
4. Integrate integrity analytics.
   AI-driven pattern recognition flags subtle trends – like slow moisture ingress –that manual reviews often miss.
   
   
5. Enforce management-of-change discipline.
   Deferred maintenance should require executive sign-off when risk scores exceed thresholds, ensuring accountability.
   
   

The Heathrow event is a stark reminder that reactive maintenance is an avoidable cost. As asset portfolios age and climate-related stresses intensify, executives must equip reliability teams with the digital tools to turn scattered sensor readings and inspection notes into decisive, risk-informed actions.

Looking to move from hindsight to foresight? Join our upcoming webinar How To Shift From A Reactive To Proactive Asset Maintenance Strategy on July 31, 2025, where we’ll unpack best practices and showcase real-world success stories. Register here for the webinar and start building the resilience your assets deserve.