Phoenix flights canceled due to 'extreme heat'

American Airlines added that the National Weather Service forcast for Wednesday (21 June) put the highest temperature below the CRJ's maximum operating temperature.

The high heat, which the National Weather Service has warned about since last week, stretches into parts of California. Las Vegas was forecast to hit 117 on Tuesday on the first day of summer, and excessive heat warnings cover nearly all of California. The south western American city is experiencing an oppressive heat wave this week, with the temperature reaching 119 degrees Fahrenheit. "It looks like (Tuesday) is the peak of the heat wave", Hernandez says. "It doesn't mean the aircraft can't physically operate at higher temperatures than what we are certified for - but this is what the certification limits us to". Other airports like LaGuardia in NY and Reagan National in Washington, D.C., could see even more days with weight restrictions.

The extreme heat in the Phoenix area, expected to reach 120 degrees on Tuesday, endangers the elderly and others with health risks and has lead to dozens of cancelled flights.

The canceled flights are part of the airline's regional flight system, and are operated by other carriers that use Bombardier aircraft, which are not permitted to fly when temperatures exceeding 118 degrees, American Airlines said. It also said, the flight changes are free of charge. The temperature in Tucson, Ariz., was 116 degrees, one degree short of its historic record.

"As the ambient temperature at a particular airport increases, in this case into the 120s at Phoenix, the amount of lift and power in aircraft engines declines, and the result is that for any given runway length, you can carry less and less payload", said Robert Mann, an industry analyst and former airline executive. American Airlines spokesman Ross Feinstein said his company has also started limiting sales on some flights to manage aircraft weight for a safe and secure take-off.

He said the latest heat wave, like all heat waves, forms within a dome of high pressure.

The Bakersfield Californian reports (http://bit.ly/2sC6IA8 ) that Benjamin R. Greene collapsed Tuesday evening shortly after running the race in 107-degree heat at a Bakersfield park.

The reason it can get so hot in the Southwest is that the humidity is so low.

Dr. Kevin Foster warned people to be extra careful around concrete, auto interiors and playground equipment, especially young children who have sensitive skin.

Officials in both Arizona and Nevada have warned residents and visitors to use extreme caution when touching doorknobs, vehicle gear shifters, and steering wheels because of the incredibly hot weather.

The density altitude is the main issue, but there also could be simple heat issues on internal components like seals that might become too soft or even melt at higher temperature, MIT aeronautics and astronautics professor R. John Hansman said.