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Heathrow to be closed all of Friday

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Flights diverted around the world

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Fire at substation still raging

(Adds fire details paragraph 3-5)

By Kate Holton, Ben Makori and Sarah Young

LONDON, March 21 (Reuters) - Britain's Heathrow Airport

was shut on Friday after a huge fire at a nearby electrical

substation knocked out its power, disrupting flight schedules

around the world.

Around 70 firefighters were tackling the blaze in the west

of London, which also knocked out the area's back-up power

system, leading to a mass outage at Heathrow, Europe's busiest

and the world's fifth-busiest airport.

Huge orange flames and plumes of black smoke could be seen

shooting into the sky during the night before firefighters said

they had the blaze under control. By early morning the roads

around Britain's biggest airport were largely deserted, except

for some passengers walking away with their luggage.

"Our fire investigators will begin their investigation and

we will continue working closely with our partners to minimise

disruption and support the community," the fire brigade said.

It said the cause of the fire was not known. Energy Minister

Ed Miliband said it did not appear to be foul play.

Heathrow said the airport, which was due to handle 1,351

flights during the day, flying up to 291,000 passengers, would

stay closed until midnight as it was experiencing a significant

power outage.

"Passengers are advised not to travel to the airport and

should contact their airline for further information," it said.

"We apologise for the inconvenience."

The fire, which was reported just after 11 p.m. (2300 GMT)

on Thursday, forced planes to divert to airports across Britain

and Europe, while many long-haul flights simply returned to

their point of departure.

Miliband said the "catastrophic" fire had prevented the

power back-up system from working and that engineers were

working to deploy a third back-up mechanism.

"With any incident like this we will want to understand why

it happened and what if any lessons it has for our

infrastructure," he told Sky News.

CHAOS AHEAD

Industry experts warned that some passengers forced to land

in Europe may have to stay in transit lounges if they lack the

visa paperwork to leave the airport. Global flight schedules

will also be affected more broadly, as many aircraft will now be

out of position.

"Heathrow is one of the major hubs of the world," said Ian

Petchenik, spokesman for flight tracking website FlightRadar24.

"This is going to disrupt airlines' operations around the

world."

British Airways, the biggest carrier at Heathrow, had 341

flights scheduled to land there on Friday.

The chaos hit shares in airlines including British Airways

parent IAG.

According to FlightRadar24, at least 120 inbound flights

were having to divert to other airports early on Friday morning.

Qantas Airways ( QUBSF ) sent its flight from Perth to Paris, a United

Airlines New York flight headed to Shannon, Ireland, and a

United Airlines flight from San Francisco was due to land in

Washington, D.C. rather than London.

Some flights from the United States were turning around

mid-air and returning to their point of departure.

Travel experts said the disruption would extend far beyond

Heathrow.

Airlines' carefully choreographed networks depend on

airplanes and crews being in specific locations at specific

times. Dozens of carriers will have to hurriedly reconfigure

their networks to move planes and crews around.

"The other question is, 'What will airlines do to deal with

the backlog of passengers?'", said travel industry analyst Henry

Harteveldt with Atmosphere Research Group. "It's going to be a

chaotic couple of days."

Some passengers turned to social media. Adrian Spender, who

works at British retailer Tesco, said in a post on X that he was

on an Airbus A380 that had been headed for Heathrow.

"#Heathrow no idea where we are going yet. Currently over

Austria."

Heathrow, and London's other major airports, have been hit

by outages in the past in recent years, most recently by an

automated gate failure and an air traffic system meltdown, both

in 2023.

A Heathrow spokesperson told Reuters in an email that there

was no clarity on when power would be restored, and they

expected significant disruption over the coming days.

On the ground in London, a number of homes and businesses

were without power. "Firefighters have led 29 people to safety

from neighbouring properties, and as a precaution, a 200-metre

cordon has been established, with around 150 people evacuated,"

the fire brigade said.