The National Weather Service in Phoenix, Arizona confirmed on Tuesday morning that a record high temperature was set Monday June 19th. The temperature was 118 degrees F. This tied the record set only a year ago in 2016. Such heat is obviously a human health concern, but there is another disruption that you may not think about. Extreme heat affects air travel. Believe it or not, it is unsafe to operate many of the airplanes currently in use by major airlines when temperatures are this hot.
Dozens of flights at Arizona's Phoenix Sky Harbor airport were delayed or canceled on Monday and Tuesday, after temperatures reached 120 degrees. The heat is especially affecting flights on smaller aircraft, particularly flights on Bombardier CRJ planes, an American Airlines spokesman said.
When it comes to getting airplanes off the ground in broiling weather, it's not the heat or the humidity. It's the air density. Hotter air gets thin, making it harder to take off and land safely.
Airplanes take off and stay aloft because of lift, the force from the movement of air underneath the plane's wings that push it upward. "As air warms up, it expands and there's fewer molecules to be under your wing," said Lou McNally, professor of applied meteorology at Embry-Riddle Aeronautical University.
With less lift, "you need more of everything. You need more thrust to take off. You need more distance (on the runway) to take off. You need more distance to land. You need more speed to land. It gets to a point for some aircraft that it gets just too much," he said.
If a plane does try to take off beyond its temperature threshold, it may keep racing down the runway and not get up in time and have to abort. And if it tries to land when the air is too thin and hot, that's not good either because it can run out of runway, McNally said.