The Heat Around the world creating problems. Some planes cannot now fly.
Extreme heat is forecast for Phoenix in Arizona today with a high of 120 degrees F which is around 49 degrees C. This has caused the cancellation of 50 American Airlines flights which use the Bombardier CRJ aircraft which have a maximum operating temperature of 118 degrees F. Some jets have higher maximum operating temperatures, Boeing 126 degrees and Airbus 127 degrees (52-53 degrees C).
Seems we are fairly safe in UK with a forecast high in the next two days of 33 degrees C only. This issue with flying is not new and in fact a heatwave shattered temperature records in 2013 in Western USA leading to similar sorts of cancellations. And indeed back in 1990 some of the asphalt melted on the tarmac at Phoenix (as it did on the A31 in UK yesterday too). But why are these high temperatures an issue? Seems there are two very different reasons:
- Extreme heat can damage the internal components of a plans.
- Heat makes it increasingly difficult for the plane to take off.Hot air is less dense. This affects the output of the engines as well as aerodynamic capabilities, increasing the required runway distance and reducing climb performance. Therefore the amount of passengers and cargo a plane can carry are often restricted when temps are very high. How much so depends on the temperature, airport elevation and the length of the available runways. And getting off the ground is only part of it: once airborne, planes have to meet specific, engine-out climb criterion, so nearby obstructions like hills and towers are another complication.
So the reality is that hot temperatures cause far more problems than cold temperatures, 
chris1957
Arcticterntalk.org 