On Friday 21 March, a fire outbreak at the North Hyde electrical substation in west London plunged Heathrow Airport into chaos.
The blaze triggered a power outage that shut down one of the world’s busiest airports for nearly a day.
Now, both the UK government and Heathrow authorities have launched urgent investigations to uncover what went wrong and how to prevent future disruptions.
Heathrow Airport: Day of Disruption
According to Cirium data, Heathrow was set for a bustling day before the outage hit. The airport had 665 departures scheduled, offering 145,094 seats, and 669 arrivals planned, with 145,836 seats.
In total, over 1,330 flights were due to move 291,000 passengers. British Airways, holding a 51% share of flights, led operations, followed by Virgin Atlantic and Lufthansa.
But the power failure stopped everything. Around 100 inbound flights were diverted to other international airports, while the rest were canceled, stranding travelers worldwide.
The impact then rippled into the weekend. Cirium reports show Heathrow was expecting over 2,520 combined departures and arrivals, amounting to 557,488 seats.
This was split between 1,219 flights on Saturday (271,677 seats) and 1,301 on Sunday (285,811 seats). Though the airport reopened by Saturday 22 March, lingering delays frustrated passengers and airlines alike.
What Happened?
The fire at North Hyde involved a transformer holding 25,000 liters of cooling oil. It not only crippled Heathrow but also cut power to over 63,000 homes and forced 150 locals to evacuate.
The Metropolitan Police’s Counter Terrorism Command initially investigated due to the site’s critical status but found no foul play.
The London Fire Brigade then took over, focusing on the faulty electrical equipment. Questions quickly arose as to why Heathrow’s backup systems failed.
UK Government Calls for Investigations
On Saturday, the UK Energy Secretary Ed Miliband ordered the National Energy System Operator (NESO) to investigate. Calling it an “unprecedented event,” Miliband tasked NESO with delivering initial findings within six weeks to the government and Ofgem, the energy regulator.
The probe will assess the resilience of the UK’s critical infrastructure. “We need to understand what happened and learn lessons,” Miliband said, vowing to bolster energy security.
Heathrow Airport Launches Review
The London airport launched its own review the same day, led by Ruth Kelly, a former Transport Secretary and independent board member. Heathrow CEO Thomas Woldbye welcomed the government’s efforts and promised full cooperation.
“We’re committed to improving our response,” he said, defending the airport’s actions despite the external cause. Operations returned to normal by March 22, but the incident left a mark.
Broader Implications
The Heathrow airport fire outage didn’t just result in a local headache. With Heathrow handling over 1,300 flights daily, the outage broadly disrupted global travel networks.
Diverted flights clogged other airports, and passengers faced delays stretching into days. The event has sparked debate about infrastructure resilience in a warming world, where extreme weather and aging systems pose growing risks.
As of 24 March 2025, both investigations are underway. The government wants systemic fixes, while Heathrow aims to strengthen its crisis playbook. For now, travelers and airlines hope the findings, which are due soon, will ensure the event is not repeated in future.
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