When Heathrow went down, they blamed the power supplier

TL;DR

Heathrow’s outage was not caused by a power loss but by an overly sensitive internal system that shut everything down in response to a minor fluctuation, revealing that their disaster recovery measures were untested for real-world chaos. Investing in infrastructure does not guarantee true resilience; resilience is proven only when systems are tested against unexpected failures. Development managers should regularly test and challenge their recovery processes to ensure they work under real conditions, not just ideal scenarios.

15 May 2025
Written by Martin Hinshelwood
1 minute read
Ethos Engineering Excellence
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When Heathrow went down, they blamed the power supplier.

A fire at one substation, they said, caused the disruption. Convenient story. But it wasn’t true.

Heathrow gets power from three independent substations. Any one of them could run the airport solo. The real failure? Their internal “resilience” system kicked in when it saw a fluctuation, not a loss. And in its attempt to “protect” the infrastructure, it shut the entire thing down.

It took all day to reboot. Not because power was unavailable, but because their disaster recovery system was too sensitive to survive a real incident.

That’s what happens when resilience is theatre. Flashy systems. Fancy architecture. And no one asking the hard question: what actually happens when things get messy?

If you haven’t tested for chaos, you’ve only prepared for comfort.

Don’t confuse infrastructure spend with resilience. Resilience is what happens when your assumptions fail.

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