Ian Caldwell wrote: > With the extremely hot temperatures in the US west, I noticed Phoenix > was 116 F, is density altitude affecting any airports / flight? Density altitude is real, especially for General Aviation aircraft, but the temperature component has only a marginal effect on high bypass turbofan performance. The greater problem is some Aircraft Operating Manuals do not have performance data for ambient temperatures this high. In the early 1990's, the AOM for a certain narrowbody in widespread use did not have data for temperatures above 115 (or may have been 110) degrees which caused a certain Phoenix-based operator of these aircraft to have to suspend operations of this type until temps cooled below the top of the charted data. Operator immediately requested and manufacturer soon provided data supplements up to 120 degrees.... - RWM