Flight reaches 801 mph as a furious jet stream packs record-breaking speeds

[dalton99a]

https://www.washingtonpost.com/weather/2019/02/19/flight-reaches-mph-furious-jet-stream-packs-record-breaking-speeds/

Flight reaches 801 mph as a furious jet stream packs record-breaking speeds
By Matthew Cappucci
February 19 at 12:31 PM

The jet stream, the high-altitude air current along which storms travel, is furious. The river of air was clocked at more than 230 mph over Long Island on Monday. That measure comes from the 250 millibar pressure level, meaning it was at a height above 75 percent of the atmosphere’s mass. It sets the record for the fastest 250 millibar wind speed ever recorded over New York and, probably, the country.

The 250 millibar level generally tends toward 30,000 feet to 35,000 feet. That’s about the same height at which commercial planes fly. Unsurprisingly, the jet stream can have big implications on how quickly aircraft reach their destination.

A Virgin Atlantic flight from Los Angeles to London peaked at a whopping 801 mph Monday evening 35,000 feet over Pennsylvania. “[N]ever ever seen this kind of tailwind in my life as a commercial pilot,” tweeted Peter James, a jet captain.

It appears that’s a record for the Boeing 787-9 twin jet, which in the past has flown at speeds up to 776 mph. The ordinary cruising speed of a Dreamliner is 561 mph, with a maximum propulsion of 587 mph. Any speed gained on top of that is thanks to Mother Nature’s helpful boost.

[pangaia]

1. The article should be clear that...

"The ordinary cruising speed of a Dreamliner is 561 mph, with a maximum propulsion of 587 mph."...refers to IAS, or indicated airspeed. That is the speed the aircraft is moving through the AIR regardless of any wind.

With zero wind, the ground speed will be the same. Thus, with the 801 mph ground speed, the aircraft is still traveling at about 570 mph IAS. Of course for the passengers it's the ground speed that counts, while for the pilots it's the air speed.

Any current pilots will, I am sure, edit my comments, but you get the idea...

[Sneederbunk]

4. So the plane did not break the red of sound?

[pangaia]

5. No. Not where it was flying.

Here is a good explanation of what is going on.


https://www.boldmethod.com/learn-to-fly/aerodynamics/coffin-corner-where-vne-and-mmo-meet/

[PoindexterOglethorpe]

2. Several decades ago I was flying from Tucson, AZ, to Chicago.

The inbound plane, from Chicago was over an hour late because of head winds. We took off nearly an hour late and made up all of the time because now we had tail winds. I always thought that was quite cool.

[CaptainTruth]

3. Years ago I was on a Tokyo to San Francisco flight & the pilot said we had a 125 mph tail wind.

He throttled back a bit, but we still got to SFO an hour and a half early. I didn't complain!

[Duppers]

7. Glad the wind was blowing in the right direction.

[Duppers]

6. OMG!

Planes have to be built well.

[Igel]

8. INteresting.

https://journals.ametsoc.org/doi/10.1175/JAS-D-15-0030.1

While rummaging around for a course I'm teaching (and still learning), I ran into atmospheric superrotation. Still can't quite explain it--consider it a work in progress.

But the jet stream is a mild example of the same kind of effect. The Earth is rotating; the atmosphere, or part of it, is rotating faster than the planet itself.

Planets like Venus have superrotation in the usual sense--the jet stream is very fast compared to Earth's (the Sun and various other solar system bodies show superrotation, too). But still, the abstract for the journal article I put at the start of this post ends, "Similarly, superrotation is favored when the convective heating strengthens, which may account for the superrotation seen in extreme global warming simulations."