This thread started with a news story about an internal memo on PHX hot weather operations.
The pertinent section of that memo is:
Oh yeah, it’s hot hot hot
PHX is expected to see high temperatures range from 116 to 119 degrees through Wednesday, which will impact our operations. Our regional partners Mesa and SkyWest won’t be able to operate their aircraft once the temperature reaches 118 degrees, and our mainline aircraft may be weight restricted. If you plan to non-rev via PHX during this time period, be prepared with alternate travel plans, or connect via a different hub if possible. To those of you dealing with the heat, stay safe, stay cool, stay hydrated and thanks for continuing to take care of our customers and each other.
The particulars, confirmed by my F/O a former CRJ driver, is that Canadair did not certify the CRJ family at temperatures above 117 degrees F. When it gets above that the aircraft are outside the certification limits, and parked until the temperature drops inside certification limits. The Airbus and Boeing's can still operate, but obviously they don't lift as much weight at those temperatures.
As to the Airline anticipating this condition, they have and Doug Parker does everything on a cost analysis basis. He needs and wants more RJ's on thinner routes out of PHX. There is this heat limitation and Doug will look at the analysis of temperature outside the limits vs. the cost of operating larger mainline aircraft on that route. He will accept that for a few days out of the year, in the afternoons only, he may not be able to operate and may have to delay flights until the evening.
It is simply a cost benefit analysis and the analysis goes to more RJ's despite the limitations.