Virgin 787 hits 800mph

[9.3]

Across the news today is the story of the Virgin 787 that hit over 800mph flying from LA to London.
Apparently it achieved this whilst flying over Pennsylvania.
Can any airline boff tell me why it was flying over Pennsylvania? I always thought the shortest route was up over Canada, Greenland, Iceland and indeed the 30 odd times I’ve flown that route that’s the way we went.
Or have things changed?

[Evanivitch]

Flight Radar 24 suggests the route taken the current LAX-LHR flight doesn't go over Philadelphia. More north of Ottawa and Montreal.

[Over over under steer]

Pilots will sometimes request specific flight paths in order to make the most of jet streams. In this case, the large differences in temperatures across USA at the moment caused a powerful jet stream that the pilot took advantage of.

[MB140]

Erm is a 787 capable of supersonic speeds was my first thought. I mean at 35000ft it’s about 650mph. I suppose with a stinking tail wind it could achieve 800mph ground speed whilst still staying subsonic airspeed.

Either way that’s some tail wind and some speed.

[sc0tt]

Would there have been a sonic boom then?

[Eric Mc]

Is that 800 mph airspeed ot groundspeed?

An aircraft can be subsonic with a 600 mph airspeed but with a 200 mph tailwind it will have an 800 mph groundspeed.

[Evanivitch]

It was ground speed.

It was flying with a 200 mph tailwind. So airspeed was well within limits.

[essayer]

It was travelling about 67,000 mph in fact (relative to the sun)

[5150]

My best effort to date. Just shy of 800mph in a 747 (aided by around 250 mph tailwind)

It's always Groundspeed that is sensationalised in the papers. . . through the air, the aircraft is flying at the same speeds it always does (We used to fly the 747 at 0.84% of the speed of sound, 787 similar. . . )

[wolfracesonic]

5150 said:

My best effort to date. Just shy of 800mph in a 747 (aided by around 250 mph tailwind)

It's always Groundspeed that is sensationalised in the papers. . . through the air, the aircraft is flying at the same speeds it always does (We used to fly the 747 at 0.84% of the speed of sound, 787 similar. . . )

Were you tempted to go into a steep dive to try and crack 800mph? 'Ladies and gentlemen... check this out!'

Seriously, with a 250mph tail wind and you did go into a dive, would the aircrafts speed, either air or ground, increase or decrease?

[Eric Mc]

The additional push of the tailwind would disappear as soon as the diving aircraft emerged from the jetstream as it no doubt would after a few seconds of descent.

[wolfracesonic]

Eric Mc said:

The additional push of the tailwind would disappear as soon as the diving aircraft emerged from the jetstream as it no doubt would after a few seconds of descent.

Yes I suppose you would leave the Jetstream pretty sharpish, not sure how 'deep' it is but say hypothetically it existed down to ground level then what, speedup/slow down?

[anonymous-user]

How early did that arrive and did it have to wait a few hours for a free gate?

[MB140]

Eric Mc said:

Is that 800 mph airspeed ot groundspeed?

An aircraft can be subsonic with a 600 mph airspeed but with a 200 mph tailwind it will have an 800 mph groundspeed.

That’s exactly what must have happened. The engines (intake) and wings on an airline won’t have been designed or cleared to fly supersonic. I am pretty certain the aircrafts onboard flight control and auto throttle computers would retard the throttles so yes I am certain the thats what happened.

[5150]

wolfracesonic said:

Seriously, with a 250mph tail wind and you did go into a dive, would the aircrafts speed, either air or ground, increase or decrease?

In a dive the airspeed will increase, in the same way your car's speed will increase when going downhill for the same throttle setting. Groundspeed will also increase if your tailwind or headwind component remained constant.

Remember, it's nothing to do with the aircraft going supersonic like Concorde used to do - that isn't happening. The speed through the air is the same it is every other day of the week - it's purely down to the wind being behind the aircraft, pushing it along.

[TIGA84]

5150 said:

wolfracesonic said:

Seriously, with a 250mph tail wind and you did go into a dive, would the aircrafts speed, either air or ground, increase or decrease?

In a dive the airspeed will increase, in the same way your car's speed will increase when going downhill for the same throttle setting. Groundspeed will also increase if your tailwind or headwind component remained constant.

Remember, it's nothing to do with the aircraft going supersonic like Concorde used to do - that isn't happening. The speed through the air is the same it is every other day of the week - it's purely down to the wind being behind the aircraft, pushing it along.

So, to appease my tiny stupid mind, its the equivalent of walking at the same speed you always do, but on the flat escalators you use at airports, hence you're travelling at normal speed + the speed of the escalator, there is no difference to the physical differences if you were walking on the floor normally?

[Tim330]

TIGA84 said:

So, to appease my tiny stupid mind, its the equivalent of walking at the same speed you always do, but on the flat escalators you use at airports, hence you're travelling at normal speed + the speed of the escalator, there is no difference to the physical differences if you were walking on the floor normally?

Your analogy is correct.

[anonymous-user]

TIGA84 said:

So, to appease my tiny stupid mind, its the equivalent of walking at the same speed you always do, but on the flat escalators you use at airports, hence you're travelling at normal speed + the speed of the escalator, there is no difference to the physical differences if you were walking on the floor normally?

Or just like being in a boat on a fast moving current.

[Mr Pointy]

We're veering dangerously close to a conveyer belt situation here.

ALARM!! ALARM!!

[anonymous-user]

Mr Pointy said:

We're veering dangerously close to a conveyer belt situation here.

ALARM!! ALARM!!

It won’t.