More than 40 flights were canceled today in Phoenix, for a reason that will probably come as a surprise to many readers even if it’s common knowledge in the aviation industry.
The BBC reports that American Airlines canceled dozens of flights that were scheduled to take off from Sky Harbor during the hottest part of the day, because it’s too hot to fly. Temperatures as high as 120 degrees Fahrenheit were forecast for the city — higher than the operating temperature of some planes.
The cancellations reportedly affected mainly regional flights using the smaller Bombardier CRJ airliners, which have a maximum operating temperature of about 118 degrees. The canceled flights were scheduled to depart between 3 p.m. and 6 p.m. local time.
The problem has to do with air density. “At higher temperatures, air has a lower density — it is thinner,” the BBC report notes. “That lower air density reduces how much lift is generated on an aircraft’s wings — a core principle in aeronautics.”