Virgin Atlantic flight VS8 from Los Angeles to London hit 801 miles per hour over Pennsylvania yesterday.
Almost 800 mph now never ever seen this kind of tailwind in my life as a commercial pilot !! (200 mph tailwind ) pic.twitter.com/0XGTkEP9EB
— Peter James (@jetpeter1) February 19, 2019
The key thing to understand here of course is the difference between air speed and ground speed. Air speed is how much faster an object is moving relative to the air around it. A 787 is not designed to go higher than 587 miles per hour in air speed. However this one wasn’t exceeding that speed.
Instead the plane’s ground speed exceeded 800 miles per hour because the wind itself gave the plane a tail wind of over 200 miles per hour.
It’s like the moving walkway at the airport. You have your own forward speed, but if you continue this velocity in an environment that is itself moving, it can propel you at an impressive rate.
That #jetstream! 🌬️ Highest wind speed at 250 millibars in the period of record for those locations near NYC, and for a jet ✈️ over PA last evening an *801* mph ground speed #wow (h/t @gdimeweather, https://t.co/MIqBu7mHNf) pic.twitter.com/RaL2HRQ5Z1
— Stu Ostro (@StuOstro) February 19, 2019
A ground speed of 801 miles per hour (obtained only briefly, as the plane remained in the jet streak only a brief period of time) is faster than the speed of sound (767 miles per hour). However the 787 wasn’t actually breaking the sound barrier as it was not moving 767 miles per hour faster than the surrounding air.
A year ago a Norwegian Boeing 787-9 flew 776 miles per hour and set a record flying between New York and London in 5 hours 13 minutes.