A significant number of airline flights leaving Phoenix Sky Harbor International Airport this week were cancelled due to weather. But the weather across the Southwest has not been stormy. Instead, it has just been too hot.
Afternoon temperatures nearing 120 degrees in Phoenix makes it dangerous for airplanes. The reason is that the whole concept of mechanical flight is based on shaping the wing with a bubble on the bottom so that air takes longer to go under the wing than over it. The result is a convergence of air underneath the wing, which causes an upward force, allowing the plane to fly. But hot air is less dense.
When the temperature is as hot as 120 degrees, there is not enough air density to create enough lift to get some planes off the ground. Runways are not long enough for some planes to gain enough ground speed to take off, making it a dangerous venture. Therefore, many flights were cancelled.
