A China Airlines Boeing 777-200LR recorded a speed of 1,329.3 km/h on a flight from Los Angeles (United States) to Taipei (Taiwan). The fact is curious because although the sound speed barrier is 1,234.8 km/h, and that the plane arrived 58 minutes early at its destination, there was no sonic boom or danger to the passengers.
Although the aircraft’s instruments showed speed values that we could understand as sonic, given that Mach 1 was technically exceeded, it was far from equaling the iconic Concorde. This scenario can be explained if we take into account two elements: a weather pattern and the relative speed between objects. Let’s look at it carefully.
The plane that exceeded 1,329 km/h
The Boeing 777-200LR have been designed to fly at a maximum speed of 950 km/h (Mach 0.89). However, as The Washington Post reports, a strong jet stream (or) that developed over the Pacific pushed the plane beyond its theoretical limits. That is, it increased its speed to a record level.
Talking about the jet stream is not something strange in the world of aviation. Pilots have been taking advantage of it since the beginning of this industry to reach their destination in less time and, above all, to save fuel. Sunday’s current, driven by the El Niño phenomenon, appeared as a tailwind for the China Airlines plane.
But, as we say, relative speed also came into play. The 1,329.3 km/h recorded on flight 5116 corresponded to its speed with respect to the ground (Ground Speed). The airspeed, that is, the speed with respect to the air, was well below Mach 1, so there was no possibility of breaking the sound barrier.
Let us remember that the flight of an airplane does not depend on the speed with respect to the ground, but rather with respect to the air flowing over its wings. We are talking about the principle of lift that allows airplanes, for example, to take off against a headwind even with a low ground speed. We can mention an example to understand it better.
Suppose we are flying at a speed of 90 km/h and encounter a persistent wind of 90 km/h. The ground speed of our plane will be 0 km/h, but this does not mean that the plane is literally falling. On the other hand, if we had a tailwind of 90 km/h, the speed with respect to the ground would be 180 km/h.
