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British Airways Sets Record for Fastest Subsonic Flight From New York to London. The flight, which took four hours and 56 minutes, reached a top speed of 825 miles per hour, according to flight-tracking data.

The flight took advantage of the strongest part of the jet stream, known as the jet streak, which created tail winds of more than 200 m.p.h. and contributed to the formation of a powerful storm Ciara, that wreaked havoc on the United Kingdom.

The average travel time between New York and London is around 6 hours 13 minutes.

According to Flightradar24, a British Airways Boeing 747 departing JFK airport on Saturday reached Heathrow in 4 hours 56 minutes.

The quickest transatlantic passenger flight was set by Concorde in 1996 – which flew at more than twice the speed of sound for a journey of two hours and 52 minutes.

Flights travelling in the opposite direction were taking more than two and a half hours longer.

https://www.rhyljournal.co.uk/news/n...s-storm-ciara/

Quote:

What's more, flight BA112 was one of three flights that beat the previously standing record set by Norwegian Airlines in 2018. It was one minute faster than a Virgin Airbus A350 flight which touched down just a few moments later, and it was three minutes faster than another Virgin flight which landed about 30 minutes afterward. Regardless, they were all far clear of the old benchmark which measured five hours and 13 minutes.
https://www.thedrive.com/news/32130/...to-london-trip

Per Wikipedia, the 747 has a cruise speed of up to 570 mph. BA112 flew at 825 mph. Be it self-propelled or assisted by tail winds, given how much faster the aircraft flew, what impact would this on the fuselage? Agree, the aircraft must be rated for much more than 570mph, but how okay is 825?

Quote:

Originally Posted by libranof1987 (Post 4748550)
https://www.thedrive.com/news/32130/...to-london-trip

Per Wikipedia, the 747 has a cruise speed of up to 570 mph. BA112 flew at 825 mph. Be it self-propelled or assisted by tail winds, given how much faster the aircraft flew, what impact would this on the fuselage? Agree, the aircraft must be rated for much more than 570mph, but how okay is 825?

Given that the speed of the wind is close to 200 mph in the same direction, the relative speed is 825-200 i.e. 625 which is closer to the cruise speed 570. Also, cruise speed is optimized for other parameters too (mileage could be one of them) and it is not the max speed.

Good for British Airways. 825 mph is quite a speed. At a typical cruising altitude of say 39,000 feet it translates to Mach 1.25! For the question asked about airframe stress. The stress on both the airframe and the engines will be the same as if the aircraft were flying at its regular cruise speed of 933 kmph {Mach 0.87} in normal weather conditions. The jetstream, the 747 was travelling in ie the North Polar jetstream, is like a river of air flowing in the atmosphere at speeds around 150 kmph on an average though speeds of 300 to even 400 kmph have been recorded. This was a freak situation with the jetsream flowing at well over over 300 kmph for a few thousand kms and in exactly the direction the aircraft wished to go. In reality jetstreams meander a lot and change course every few hours so here we had not only an exceptionally fast flowing river {of air} but one that held course long enough for the flight to set a record. In this case it seems the British Airways pilot, in order to set a record, may have pushed the machine to 625 mph {~1000 kmph or Mach 0.95} which is close to its maximum high altitude speed of Mach 0.97. While I don't know about the 747-400 but in the past a Douglas DC-8 has been dived, in 1961, to a little over Mach 1.01!!

While we are at it I thought of penning down a short summary of the jet stream as many of our readers travel by air extensively.

Fastest Subsonic Flight from New York to London (under 5 hours)-jetstreamconfig.jpg
There are four primary jetstreams - the North Polar and South Polar and two in the sub-tropics in either hemisphere. The North Polar gets the most publicity as its latitudes of around 40 to 60 degrees North straddle the busy transatlantic routes. Also flows at 30,000 to 40,000 feet just where airliners love to cruise. Vertically it is a very thin band of air but horizontally it could be a few hundred kms wide like a very wide and very shallow river. The South Polar at around 50 to 60 degrees south experiences limited airline traffic. The sub tropical jet streams at around 20 degrees North and South flow mainly between 40,000 and 53,000 feet though at times it descends to 30,000 feet. The sub-tropical jet streams are narrower and less intense than the Polar ones.


Fastest Subsonic Flight from New York to London (under 5 hours)-1920pxjetcrosssection.svg.png
The earth's atmosphere has three giant air circulations, like giant Ferris wheels shown in this diagramme - the Polar, Ferrel and Hadley cells. The points of intersection of these circulating masses is where the jetstreams flow. The causes of the jetstreams are more complex but primarily driven by these ferris wheels and the rotation of the earth on its axis.

I was once on an Air India B747-400 that was delayed from JFK-LHR due to a thunderstorm at JFK. Once we took off, we hit a good jet stream resulting in a flight time of about 5 hours 40 minutes or so. and the plane actually made the schedule inspite of the ground delay!

Quote:

Originally Posted by libranof1987 (Post 4748550)
Per Wikipedia, the 747 has a cruise speed of up to 570 mph. BA112 flew at 825 mph. Be it self-propelled or assisted by tail winds, given how much faster the aircraft flew, what impact would this on the fuselage? Agree, the aircraft must be rated for much more than 570mph, but how okay is 825?


It is perfectly fine, no impact on the fuselage, none whatsoever. When discussing speeds in aviation, there are two different kind of speeds. The most important is airspeed. Airspeed is the speed at which the air passes over the wings and the fuselage. It is extremely important, because it is airspeed that provides the necessary lift for an airplane to actually fly.

Ground speed is the result of airspeed plus and minus wind speed. No matter what the direction of the wind or the strength, the airspeed is what matter to the plane in terms of lift and to your concern, stress on fuselage and or wings etc.

If this plane had been following the same route going the opposite way, its ground speed would have been greatly reduced to probably about the same amount, around 255mph. So its speed over the ground would have been around 315mph. But the airspeed would have been the same going either way.

When pilots make a flight plan, it is not so much the physical distance that is relevant, but more on how long it will take to get there. Which depends heavily on the wind direction and wind force.

Jeroen

If I remember some of my European trips over the last few years, I guess the Europe to India time was almost always shorter than the other way round ( at least whenever I noticed ). Is it just a coincidence ( or bad sampling), or is it that jet-streams are mostly unidirectional?

Quote:

Originally Posted by Bigzero (Post 4749843)
If I remember some of my European trips over the last few years, I guess the Europe to India time was almost always shorter than the other way round ( at least whenever I noticed ). Is it just a coincidence ( or bad sampling), or is it that jet-streams are mostly unidirectional?


The latter, jet streams, more or less west to east. They will shift a bit north and south. The main direction west east is due to the rotation of the earth, the north south is more a thermal effect,
Jeroen

Wow! As always your analysis, short narration in simple term makes the subject interesting, so easy to understand.

Was about to close this thread thinking 'nah, this is not the thread to go in detail' (even ignored news coverage in various portals) and then saw your description. :D


Quote:

Originally Posted by V.Narayan (Post 4749369)
The earth's atmosphere has three giant air circulations, like giant Ferris wheels shown in this diagramme - the Polar, Ferrel and Hadley cells. The points of intersection of these circulating masses is where the jetstreams flow. The causes of the jetstreams are more complex but primarily driven by these ferris wheels and the rotation of the earth on its axis.


This recent BA 747 speed record brings out the competition amongst 747 pilots. I am a member of a 747 Group on Facebook and a few pilots are posting evidence of their speeds. I thought I would share as it shows some interesting details:

This one is very recent, last week

Have a look at the display. This is the so called ND or navigation display. It show the pilot the rout, map contour, weather, terrain etc. And it also shows

GS 720: Ground Speed 720 knots = 829 mph = 1333 km / h
TAS 522: True Air Speed 522 knots = 601 mph = 967 km / h

243o / 198: Indicates a wind of 198 knots coming from 243o.
HDG 098 MAG: the plane is flying a magnetic heading of 069 degrees
An arrow indicating the wind direction

Fastest Subsonic Flight from New York to London (under 5 hours)-84880308_10213104380837797_1540701727961907200_n.jpg

So you see the wind is almost directly from behind. The difference between GS and TAS is 198. If the wind was not directly from behind, the computer will also calculate the cross and tailwind component.

Another example, even faster!

Fastest Subsonic Flight from New York to London (under 5 hours)-84618279_2774331069272438_243797573674991616_n.jpg

So these speeds are not that unusual, although it is unusual to have such a tailwind for so many hours.

As I explained before, the lift developed, and thus also all the stresses on the airframe and wings are related to the TAS not the Ground Speed at all.

Although you might be going very fast these days it is no guarantee you will land earlier. It is all done to how busy the various bit of air space are and whether you can get the appropriate time slot to cross the ocean, land etc.

I just heard a story from a friend of mine who made also a very fast ocean crossing, but was told to hold for an hour and a half at his destination airport due to heavy traffic and limited run ways in operations due to heavy wind!

Jeroen

Just came across this little video I thought I would share.

It really illustrates well the difference between airspeed and ground speed and correlation with head and tail wind
Here you see a little single engine airplane flying at 45 knots (airspeed) into a 45 knots head wind. The ground speed is 0 (zero). This little plane is not going anywhere, it is stationary above the ground!

https://imgur.com/gallery/4NHsqiG

Jeroen

Stupid question, can a pilot save fuel by lessening thrust due to sufficient tailwinds and actually save an airline money on a route if this was a regular occurrence ?

Quote:

Originally Posted by D33-PAC (Post 4764502)
Stupid question, can a pilot save fuel by lessening thrust due to sufficient tailwinds and actually save an airline money on a route if this was a regular occurrence ?

As the saying goes, “there are no stupid questions” and this is a very good question.

The short answer is yes, but in practice it is a little bit more complex.

When making a flight plan it is not so much the geographical distance of the route, but the flight time required to cover that route which is relevant. Flight time will be a combination of what wind speeds and directions are you likely to encounter. But also at which altitude can you fly. Jet planes, for a given weight have a given altitude that will give you the best fuel efficiency.

As you burn off the fuel the aircraft becomes lighter and you need to ascent to a higher altitude to become even more efficient. In theory, ideally you would be climbing constantly at a very low rate of vertical speed. That is not very practical, planes cruise horizontally and will request a higher altitude by means of what they call a step climb. These step climbs tend to be standardised. Depending where you are in the world it is usually steps of 2000-4000 feet. Your flight computer will tell you when your next step climb is due and you will ask ATC for permission to do so when you reach that point on your route.

In theory with a heavy tail wind you can reduce thrust and save fuel and still arrive on time. In practice that might not be possible. Also, not only is there a optimal cruising altitude, for each weight/altitude there is also an optimal air speed. The band with is quite narrow. You slow down too much and your fuel efficiency decreases quickly and it might not be offset by the push of the tail wind.

Also, a lot of the airways are really busy. Everybody has to maintain certain horizontal and vertical superstation. With big speed differences on the same route on the same altitude that is going to be a problem.

The other consideration is ATC restrictions, be it on route, on departure and landing slots. It all needs to align or you are going to be burning fuel waiting in hold or similar.

There is an ATC video on Youtube; It is the recording at some US airport. Very busy, heavy congestion in the air. Lots of pilots and planes waiting for a slot to get going. The controller offers the pilots waiting for a departure slot on a particular route at or around 16.000 feet. There are no takers, jets will burn a ridiculous amount of fuel at that altitude. Better wait!

Jeroen


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