This KLM captain crossed the Atlantic in less than 6 hours on a 747

What's it like to cross the Atlantic at more than 800 mph?

That's a question a number of pilots can answer after a strong winter storm last week that generated unusually fast jet stream winds.

How strong? One British Airways flight shattered the subsonic speed record between New York and London, crossing the Atlantic in just 4 hours, 56 minutes on Feb. 7. British Airways Flight 112 was aided by tailwinds that pushed it to make the fastest crossing between the two cities by a non-supersonic passenger jet.

But that flight wasn't the only one to make an extraordinarily quick transatlantic crossing.

KLM Flight 644 was another example, reaching a speed over the ground of 819 mph between New York JFK and Amsterdam — a record for the carrier, according to KLM spokesman Arturo Diaz. The flight, operated by a Boeing 747-400, completed the normally seven-hour Atlantic crossing in about 5 hours, 20 minutes, according to flight Capt. Peter Bakker.

“It’s something special, but at the moment, you don't realize it,” he said in an interview with TPG about the flight, which also came on Feb. 7. “I’ve been flying the 7-4 for 30 years now and I thought ‘Wow, this is going really fast today,’" he added, referring to the 747 by an abbreviation common among crew members.

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Bakker noted that the tailwind wasn't pushing the plane for the whole duration of the flight, but the 747 benefited from the boost for about three or four hours, particularly over Newfoundland. Of course, flight KL644 did not go supersonic, and neither did any of the other planes pushed by the jet stream to great speeds. That's because ground speed, aided by the wind, is not airspeed, which is the speed of a plane relative to the air around it. The latter is the one that determines whether a plane is supersonic or not — and after Concorde's retirement in 2003, there are no civilian supersonic airliners.

The jet stream only flows one way, west to east. But westbound flights weren't affected as strongly, Bakker said, because they were able to route around the strongest headwinds.

Strong winds can sometimes mean heavy turbulence, but that was not the case last week, Bakker said.

Supersonic?: No, your flight didn’t go supersonic. That was just really fast wind.

"It was a surprise to me that it wasn’t really turbulent. The wind came in gradually and faded very gradually," he said. When the wind picks up and dies down suddenly, it's much more likely to result in a bumpy ride, he explained.

For passengers in the cabin, that meant there wasn't much difference from any other journey on the route — aside from the faster flight time.

“I don’t think there’s a special sensation for passengers in the sense of aircraft behavior," Bakker said.

Flights traveling more than 800 mph with a tailwind might sound extreme, but Bakker said they don't generally require any special planning.

“We took a little extra fuel just to be on the safe side," Bakker said. “Nine out of 10 times, the winds never are as fast as they predict," he continued, "except on this day, it was even better than they predicted.”

For Bakker, the speedy flight was particularly special because it came just days before his retirement. It also came near the end of the 747's run, too — at least at KLM.

Related: Farewell to a queen: What it was like to be on the last revenue flight of a Qantas 747-400

“That was of course, something special, to experience something like this,” he said on Thursday. “Especially because the 7-4 is going to retire next year from KLM and I’m going to retire in one flight, my last flight is tomorrow.”

Bakker doesn't expect his final flight to be quite as eventful, but he said pilots are always prepared for every possibility.

“Maybe we’ll make it the longest flight from Amsterdam to L.A., we’ll make it 14 hours instead of 10 – just kidding,” he said. “Of course it will be a special flight because it’s my last flight.”

Editor's note: A previous version of this article had an inaccurate headline. The headline has been updated to reflect that the flight crossed the Atlantic in 5 hours and 20 minutes.

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