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 have found 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.” (Jamaica Gleaner/AP)