Weather forecasts for Phoenix, Arizona, are predicting temperatures soaring to around 120 degrees Fahrenheit on Tuesday, leading to the cancellation of around 20 flights, as some of the planes have problems taking off at higher temperatures. While the previous all-time record for heat in Phoenix was on June 26, 1990, when thermometers reached 122 degrees Fahrenheit, the current heat wave will reportedly come pretty close.

American Airlines cancels flights over Phoenix heat

American Airlines has announced the cancellation of dozens of flights which were set to take off from the Phoenix Sky Harbor airport during the hottest time of the day.

According to Fox News, the cancellations mainly hit regional flights on the Bombardier CRJ airliners, whose maximum operating temperature is around 118 degrees Fahrenheit. All the flights affected would have been taking off between 15:00 and 18:00 local time.

Taking off in the extreme heat is the problem

The BBC explains the reason for the flight cancellations as being that with higher temperatures the air has a lower density. This apparently reduces the amount of lift generated by a plane’s wings. This, in turn, would lead to the aircraft’s engines having to generate more thrust, or need more runway length, in order to safely get airborne.

Reportedly in countries that regularly see higher temperatures, like those in South America and the Middle East, flights in similar planes are generally scheduled for the evening or nighttime, when the temperatures are cooler.

Larger planes have no problem with Phoenix temperatures

American Airlines did say in their statement that the larger aircraft, including Boeing 747s and Airbus planes, are not affected by the extreme heat in Phoenix as they have a higher operating temperature and their engines are able to handle the situation.

Reportedly those planes can operate with no problem even at temperatures of between 126 and 127 degrees Fahrenheit, higher than those expected on Tuesday.

American Airlines flight changes are free of charge

The airline did say in their statement that all flight changes would be Free Of Charge to travelers. They have recommended customers get in touch with American Airlines' agents to rebook their flights or ask for their money to be refunded. So far, American Airlines appears to be the only airline to be affected and cancel flights over the extreme heat.