Is that realistic?

At the moment i fly from Ghuangzou to Los Angeles and 2H away from the coast i see 145kts tailwind that pushes me up to a GS of 647kts over the pacific.

I think the speed of sound is around that 666kts when i remember that right, does that mean that i am flying a bit und the speed of sound?

Ground speed is not the same at airspeed.

Check this out for more information.


THANK YOU :o Now i understand that. Thanks, Topic can be closed