JACKSONVILLE, Fla. — Aircraft traveling from North America to Europe last week, neared the speed of sound over ground at times. What made these flights truly exceptional, was the powerful influence of a jet stream, a high-altitude, fast-moving air current that can significantly impact an aircraft's speed and efficiency.
Jet streams are narrow bands of high-velocity winds that blow from west to east at altitudes of around 30,000 to 40,000 feet above the Earth's surface. These high-altitude winds are created by the temperature contrast between the Arctic region and the mid-latitudes, as they can reach astonishing speeds of up to 250 miles per hour. While they play a crucial role in shaping global weather patterns, they also serve as a natural ally for aviation when harnessed properly.
This phenomenon was clearly demonstrated by several recent flights, including one by Etihad Airlines (ETD76T) that was observed traveling at 630 knots groundspeed. In another instance last week, a flight was documented reaching a velocity approaching 800 miles per hour. While these speeds are undeniably impressive, they still fall short of the record achieved by a British airline in 2020, when a flight reached a staggering 825 miles per hour.
However, it's crucial to clarify that these flights did not breach the sound barrier. A sonic boom, the characteristic shockwave produced when an object exceeds the speed of sound, is generated based on the aircraft's airspeed rather than its groundspeed. To illustrate, consider a raft floating downstream in a river. Although the raft may be traveling swiftly over the riverbed, it is essentially moving in harmony with the water beneath it. Similarly, an aircraft's groundspeed reflects its movement relative to the Earth's surface, whereas the speed of sound and the potential for a sonic boom, are related to its airspeed.
While a jet stream can be a pilot's best friend, it can also however, pose challenges when it comes to turbulence and unpredictable weather conditions. Not to mention, flights going in the opposite direction from Europe to the United States, can be spotted traveling much slower than normal.
