How A British Airways 747 Once Flew 825mph

British Airways’ Boeing 747s used to be a common sight on the lucrative route between London Heathrow and New York JFK. However, they were more than just an iconic way to cross the North Atlantic Ocean. Indeed, one such jumbo jet once broke the record for the fastest flight on this route, reaching a maximum speed of 825 mph (1,328 km/h). But how?

British Airways Boeing 747
BA flew the 747 on several of its UK-US routes. Photo: Vincenzo Pace | Simple Flying

Helped by the jetstream

February 2020 saw a British Airways Boeing 747-400 break the record for the fastest-ever subsonic scheduled commercial flight between New York and London. A quick browse of the airline’s schedules shows that this journey typically takes around seven hours.

However, according to US science and technology magazine Popular Mechanics, a BA jumbo shaved some two hours off this time 18 months ago by completing the journey in a record-breaking four hours and 56 minutes! Aided by a more powerful jetstream than usual, this rapid journey saw the 747 reach a top speed of 825 mph.

The jetstream means that eastbound transatlantic flights are often quicker than westbound ones. Popular Mechanics reports that the reason for it being so powerful on this occasion was a ‘bomb cyclone’ near Greenland. This generated hurricane-force winds at its epicenter, with wind speeds still at an impressive 200 mph further away.

British Airways Boeing 747
Jetstream winds helped the 747 reach London in under 5 hours. Photo: Vincenzo Pace | Simple Flying

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Airspeed vs ground speed

It is important, in cases such as this, to make a distinction between airspeed and ground speed. It is this difference that means that, while the flight’s speed appears to have been supersonic, it didn’t actually break the sound barrier. The impressive 825mph figure that the wind-assisted BA 747 clocked was a ground speed measurement.

Ground speed is the speed at which the aircraft would travel if it were at ground level. This is why the flight arrived nearly two hours early. However, the figure is a combination of the plane’s airspeed and its tailwind. On a completely still day, ground speed and airspeed would be equal. However, in this instance, there was a tailwind of more than 200 mph (322 km/h).

As such, the 747’s airspeed (its speed relative to the air around it at its cruising altitude) remained subsonic, hence this seemingly supersonic flight didn’t break the sound barrier.

British Airways, Boeing 747, Retirement
While the 747’s ground speed was supersonic, its airspeed was not. Photo: Vincenzo Pace | Simple Flying

A similar feat by Virgin Atlantic

While airlines often profit from jetstream winds to achieve faster transatlantic crossings, stories of supersonic ground speeds are rare. That being said, British Airways isn’t the only airline to have achieved such a feat. Indeed, a Virgin Atlantic Boeing 787 also managed to do so in February 2019, while operating a flight from Los Angeles to London.

Aided by a strong tailwind, the Dreamliner topped out at 801 mph (1,289 km/h). Virgin Atlantic founder Sir Richard Branson gleefully took to Twitter at the time to explain that this was “faster than any other commercial non-supersonic plane in history.”

Of course, the New York-Heathrow BA 747 flight a year later went on to steal this title. That being said, a Virgin A350 on the same route came in just a few minutes slower. As Captain Chris Pohl detailed on Instagram, his A350 hit a staggering 833mph (1340 km/h).

Have you ever been on a significantly wind-assisted flight like this one? Perhaps you even traveled on this very service? Let us know your thoughts and experiences in the comments!

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