First plane lands at London's Heathrow since a fire cut power to Europe's busiest airport

LONDON — The first plane landed at Heathrow Airport late Friday, about 18 hours after an inferno at an electrical substation caused a power outage that shuttered Europe’s busiest air travel hub.

The British Airways jet touched down just before sunset after Heathrow lifted its closure order that disrupted global travel for hundreds of thousands of passengers.

At least 1,350 flights to and from Heathrow were affected, flight tracking service FlightRadar 24 said, and the impact was likely to last several days as passengers try to reschedule their travel and airlines work to reposition aircraft and crews.

Authorities do not know what caused the fire but so far found have no evidence it was suspicious.

Residents in west London described hearing a large explosion, followed by a fireball and clouds of smoke, when the blaze ripped through the electrical substation near the airport.

About 120 flights were in the air when the closure was announced, with some turned around and others diverted to Gatwick Airport outside London, Charles de Gaulle Airport near Paris or Ireland’s Shannon Airport, tracking services showed.

Lawrence Hayes was most of the way to London from New York when Virgin Atlantic announced the plane was being diverted to Glasgow.

‘‘It was a red-eye flight and I’d already had a full day, so I don’t even know how long I’ve been up for,‘’ Hayes told the BBC as he was getting off the plane in Scotland. “Luckily I managed to get hold of my wife and she’s kindly booked me a train ticket to get back to Euston, but it’s going to be an incredibly long day.‘’

Heathrow is one of the world’s busiest airports for international travel. It had its busiest January on record earlier this year, with more than 6.3 million passengers, up more than 5% from the same period last year.

Still, the disruption Friday fell short of the one caused by the 2010 eruption of Iceland’s Eyjafjallajokull volcano, which spewed clouds of ash into the atmosphere and created trans-Atlantic air travel chaos for months.

Unclear what caused the fire but foul play isn’t suspected

It was too early to determine what sparked the huge blaze about 2 miles (3 kilometers) from the airport, but there’s ‘’no suggestion'' of foul play, Energy Secretary Ed Miliband said.

The Metropolitan Police force said counterterrorism detectives were leading the investigation because of their ability to find the cause quickly and because of the location of the electrical substation fire and its impact on critical national infrastructure.

Heathrow said its backup power supply designed for emergencies worked as expected, but it was not enough to run the whole airport. It said it had no choice but to close the airport for the day.

‘‘We expect significant disruption over the coming days, and passengers should not travel to the airport under any circumstances until the airport reopens," the airport said.

The widespread impact of the fire that took seven hours to control led to criticism that Britain was ill prepared for disaster or some type of attack if a single blaze could shut down Europe’s busiest airport.

‘‘The U.K.‘s critical national infrastructure is not sufficiently hardened for anywhere near the level it would need to be at to give us confidence this won’t happen again,‘’ said Alan Mendoza, the executive director of the Henry Jackson Society, a security think tank. ‘’If one fire can shut down Heathrow ... it tells you something’s badly wrong with our system of management of such disasters.‘’

Tom Wells, a spokesperson for Prime Minister Keir Starmer, acknowledged that authorities had questions to answer and said a rigorous investigation was needed to make sure ‘’this scale of disruption does not happen again.‘’

Heathrow — where the U.K. government plans to build a third runway — was at the heart of a shorter disruption in 2023 when Britain’s air traffic control system was hit by a breakdown that slowed takeoffs and landings across the U.K. on one of the busiest travel days of the year.

Disruption could last days

Heathrow had originally said it expected to reopen just before midnight, but anticipated ‘’significant disruption over the coming days and passengers should not travel to the airport under any circumstances until the airport reopens.‘’

After Heathrow announced it would reopen, British Airways said it was cleared for eight long-haul flights to depart from Heathrow after 7 p.m. United Airlines said it expected to operate most of its Friday departures to London.

Even after flights resume, it will take several days to mobilize planes, cargo carriers, and crews and rebook passengers, said aviation consultant Anita Mendiratta.

‘‘It’s not only about resuming with tomorrow’s flights, it’s the backlog and the implications that have taken place,‘’ she said.

Diverted, canceled and in limbo

Mark Doherty and his wife were halfway across the Atlantic when the inflight map showed their flight from New York’s John F. Kennedy Airport to Heathrow was turning around.

‘‘I was like, you’re joking,‘’ Doherty said before the pilot told passengers they were heading back to New York.

Doherty called the situation ‘’typical England — got no back-up plan for something happens like this. There’s no contingency plan.‘’

At Heathrow, a family of five traveling to Dallas showed up in the hopes their flight home — still listed as delayed — would take off.

But when Andrea Sri brought her brother, sister-in-law and their three children to the airport, they were told by police that there would be no flight.

‘‘It was a waste of time. Very confusing,‘’ said Sri, who lives in London. ‘’We tried to get in touch with British Airways, but they don’t open their telephone line until 8 a.m.‘’

Travelers who were diverted to other cities found themselves trying to book travel onward to London. Qantas airlines sent flights from Singapore and Perth, Australia, to Paris, where it said it would bus people to London, a process likely to also include a train shuttle beneath the English Channel.

Budget airline Ryanair, which doesn’t operate out of Heathrow, said it added eight ‘’rescue flights'' between Dublin and Stansted, another London airport, to transport stranded passengers Friday and Saturday.

National Rail canceled all trains to and from the airport.

Blaze lit up the sky and darkened homes

Matthew Muirhead was working Thursday night near Heathrow when he stepped outside with a colleague and noticed smoke rising from an electrical substation and heard sirens.

‘‘We saw a bright flash of white, and all the lights in town went out,‘’ he said.

The London Fire Brigade sent 10 engines and around 70 firefighters to control the blaze and about 150 people were evacuated from their homes near the power station.

The blaze knocked out power to 67,000 customers, though most of it was restored by daybreak, the fire brigade said.

Flights normally begin landing and taking off at Heathrow at 6 a.m. due to nighttime flying restrictions. But the skies were silent Friday morning.

‘‘Living near Heathrow is noisy, there are planes every 90 seconds or so, plus the constant hum of traffic, but you get used to it, to the point of no longer noticing,‘’ said James Henderson, who has lived next to the airport for more than 20 years. ‘’Today is different, you can hear the birds singing.‘’

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Associated Press writers Stefanie Dazio in Berlin, Yirmiyan Arthur in Kohima, India, John Minchillo in New York, Hallie Golden in Seattle, and Christie Hampton, Brian Hannon and David Cohen in Bangkok, contributed.