Commercial Flight Hits Over 800 MPH In Jet Stream
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 typical cruising speed for a plane of a Boeing 787-9 is only around 560 mph. So when a Virgin Atlantic flight making the long haul from Los Angeles to London hit a ground speed of at least 801 mph, it was insane. How did it happen? The plane hit a streak of fast-moving air in the jet stream over Pennsylvania. You probably know that breaking the sound barrier over land is illegal, but despite surpassing the speed required to break the sound barrier, there was no sonic boom.
The flight was being tracked on Flight Aware where the data was seen and was tweeted out by meteorology teacher Stu Ostro:
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
Although the speed of sound is typically 767 mph it does vary based on factors like altitude, air temperature, pressure. Even still, the plane hit speeds well above that mark. However, that explains why there was no sonic boom for this particular flight.
The Washington Post explains that "commercial aircraft ordinarily can’t break the sound barrier, because they’re not designed to handle the sudden increase in drag and other aerodynamic effects associated with those speeds. Despite a ground speed that high, the plane didn’t come close to reaching that threshold because it was embedded in the swiftly moving air."
And if you're wondering, yes, the plane managed to arrive 48 minutes early in London.