(Bloomberg) — London Heathrow’s unprecedented blackout on Friday has put the airport’s reliance on potentially vulnerable infrastructure into focus, at a time when the biggest UK hub is lobbying for an ambitious expansion plan.
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A fire late Thursday at a nearby electrical substation cut off the power supply to Heathrow, bringing flights to a standstill for almost all of Friday. While backup systems kicked in, they only allow the hub to land some aircraft and evacuate passengers, but not to support full operations. Only by late on Friday did a few flights resume, mainly to repatriate dislocated passengers.
The public blowback to the outage was swift, with Willie Walsh, the former chief executive officer of British Airways parent IAG SA and now IATA director, saying it’s “yet another case of Heathrow letting down both travelers and airlines.”
Walsh said it’s a “clear planning failure by the airport” if critical national infrastructure relies on one energy source without an alternative.
At the same time, given that Europe’s busiest airport uses as much energy as a small city, keeping enough power capacity in reserve to meet such demand is complicated. Heathrow hasn’t suffered an outage on that scale in at least two decades, with previous disruptions typically caused by strikes, weather, or air-traffic control computer glitches.
“Lots of people would say it seems like a greater level of redundancy could have been built in, but ultimately you have to pay for that,” said Robin Preece, a lecturer in future power systems at the University of Manchester. “It’s a question of how much you’re willing to pay for situations which are unlikely to arise.”
Airports around the UK are connected to substations in a similar way to Heathrow, and it’s not unusual for some to be dependent on a single source, Preece said. What’s different this time is the fire and catastrophic failure that ensued, Preece said in an interview.
While infrequent, such fires can be caused by various factors, said John Loughhead, an electrical engineering expert at the Institution of Engineering and Technology. Some equipment in the substations, such as oil and circuit breakers, are flammable or can trigger explosions.
“It is surprising that, as a part of our national critical infrastructure, Heathrow does not have an alternative supply point in case of accidents like this,” he said in an email.

